FOUS30 KWBC 281515
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1115 AM EDT Sat Mar 28 2026

Day 1
Valid 16Z Sat Mar 28 2026 - 12Z Sun Mar 29 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

...16Z Update...

No changes were needed with the blank outlook for the rest of today
and tonight. In coordination with MFL/Miami, FL forecast office,
there was agreement that the flooding threat in south Florida
remains sub-Marginal. The CAMs are in good agreement that any
convection that forms today will develop west of the urban I-95
corridor, then track southwest across relatively rural areas around
Lake Okeechobee and into the Everglades and the Naples/Marco
Island area. This should preclude any flooding concerns, especially
given the ongoing drought and below average soil moisture levels
broadly across south Florida.

Wegman

...Previous Discussion...

We will keep an eye on south FL, where convection is likely this
afternoon into tonight. However, at this time the flash flood risk
looks low. Initial convective development along the east coast of
FL should move off to the southwest, limiting rainfall rate
duration. Additional development this evening into tonight near and
post frontal passage should generally stay transient in nature,
with a downward trend in CAPE also expected overnight.

The 00z HREF and REFS neighborhood probabilities of exceeding 3"
are over 50%, but generally focused over inland areas of south
FL...and 5" exceedance probabilities from the HREF are zero. For a
Marginal risk we would like to see the higher 3" probabilities
focused across the coastal urban areas and/or significantly higher
5" probabilities. Thus will continue with no risk area.

Chenard


Day 2
Valid 12Z Sun Mar 29 2026 - 12Z Mon Mar 30 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Additional showers and thunderstorms are expected across southeast
FL, with a stream of activity potentially focused near the urban
corridor. However, most model instability forecasts are below 1000
j/kg, and thus currently not expecting rainfall rates to be high
enough for flash flooding, but we will continue to monitor.

Chenard


Day 3
Valid 12Z Mon Mar 30 2026 - 12Z Tue Mar 31 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

There is a non-zero risk for minor urban and small stream flooding
across portions of MI, northwest PA and western NY Monday into
Monday night. There is a notable increase in instability, with
values exceeding 1000 j/kg. This is anomalous for the time of
year, especially over portions of MI where the ECMWF EFI for CAPE
is over 0.9. Combine this CAPE with above average PWs and strong
moisture transport and we would expect there to be a potential for
heavy rainfall rates. At the moment, not really seeing enough of a
consistent model QPF signal to justify introducing a risk area, but
we will have to continue to monitor trends, especially as we move
more into the high res model timeframe.

Chenard
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 290820
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
420 AM EDT Sun Mar 29 2026

Day 1
Valid 12Z Sun Mar 29 2026 - 12Z Mon Mar 30 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Chenard


Day 2
Valid 12Z Mon Mar 30 2026 - 12Z Tue Mar 31 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

An uptick in convective activity is expected Monday night into
Tuesday morning across portions of MI into western PA/NY. There is
a strong surge of moisture and instability, and thus locally heavy
rainfall is possible. Overall it seems like the better chance of
localized flash flooding is after 12z Tuesday as the duration of
rain makes hydrologic conditions more sensitive by then. So we
will hold off on introducing any day 2 risk area and let the day 3
Marginal cover the threat. But we will continue to monitor trends
as the event gets more in range of the high res models today.

Chenard


Day 3
Valid 12Z Tue Mar 31 2026 - 12Z Wed Apr 01 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE OHIO VALLEY INTO NEW YORK AND VERMONT...

A stationary front positioned over NY will likely be a focus for
scattered convection to start the period Tuesday morning. The
front is not forecast to move much during the day, likely
supporting periodic rounds of scattered showers and thunderstorms.
An area of low pressure riding along the front should increase
forcing and convergence by Tuesday evening, resulting in an uptick
in rainfall coverage.

Moisture parameters are impressive with this system...PWs are
forecast to be near late March to early April max values, and IVT
increases above the climatological 90th percentile. Instability is
more marginal, and will likely reduce max rainfall rate potential
and act as a limiting factor for flash flooding. However, there is
some instability forecast in the morning, and by evening the
increasing forcing/convergence could help offset decreasing
instability. Thus while not widespread, some localized hourly
rainfall around 1" seems plausible.

Model consensus rainfall magnitudes are generally in the 1-2"
range, although with multiple rounds likely, there is a potential
for more localized swaths getting into the 2-4" range. These
higher amounts are most likely over portions of far northeast OH,
far northwest PA and into southwest NY...near the stationary front
and within a corridor where instability has a better chance of
persisting. A bit farther northeast into upstate NY and VT, some
snow melt contribution could also aid in minor runoff concerns.
Farther southwest over IN and OH instability is higher supporting
greater rainfall rates, but duration should be shorter with a
quicker frontal progression. Soil and streamflow conditions are
more conducive for flood impacts over portions of OH and IN, but
dry out with southwest extent into IL and MO. Thus while convection
will extend into these latter areas as well, for now we will stop
the Marginal risk near the IL/IN border.

Overall the primary threat is for localized flooding in areas
where training, or multiple convective rounds, occur near the
stationary front...or where higher short duration rates intersect
sensitive urban areas.

Chenard

$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 300852
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
452 AM EDT Mon Mar 30 2026

Day 1
Valid 12Z Mon Mar 30 2026 - 12Z Tue Mar 31 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

While the better setup for localized flash flooding occurs after
12Z, there will be the presence of an increasing surge of moisture
and instability leading to the potential for localized heavy rainfall.

Campbell


Day 2
Valid 12Z Tue Mar 31 2026 - 12Z Wed Apr 01 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE GREAT LAKES INTO NORTHERN NEW ENGLAND...

The latest guidance has continued to see an uptick in forecast
amounts across the lower Great lakes and New England regions for
this period. Impressive moisture advection characterized by IVT
values exceeding 750 kg/ms in spots will move northeast along a
slow-moving front across the Great Lakes. This will allow near
record amounts of atmospheric moisture for this time of year, with
PWATs exceeding 1.25 inches at times to move into the Marginal Risk
area. Instability will increase towards the south and west, but
drier antecedent soil conditions and weaker forcing should cancel
out those supporting meteorological factors along the Mississippi
River and the Ozarks. During this period a stationary front draped
across New York remain in place, providing focus for rounds of scattered convection to fire up. By Tuesday evening rainfall coverage should
increase as an area of low pressure tracks along the frontal
boundary. Guidance continues to favor areal averages of 1-2 inches
for the region, however with training possible, localized higher
amounts of 2-4 inches may materialize over the northeast Ohio, far
northwest PA and into southwest NY...near the stationary front and
within a corridor where instability has a better chance of persisting.

Campbell/Chenard


Day 3
Valid 12Z Wed Apr 01 2026 - 12Z Thu Apr 02 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL STRETCHING FROM
TEXAS TO THE MIDWEST/UPPER MIDWEST...

The central portion of the country is shaping up for heavy rainfall
as a frontal system extending from the Northeast to the Mid-South
taps into Gulf moisture advecting northward. Multiple rounds of convection
are expected to fire up across central and eastern CONUS given the
upper level support for sustained rainfall potential. Local
flooding may arise over portions of the Southern Plains, Lower and Mid-Mississippi Valley. The general footprint of the rainfall
shield has trended a bit west from the previous cycle thus
requiring a western adjustment of the Marginal Risk area.
Consensus continues to favor the highest QPF to focus over eastern
Oklahoma, southeast Kansas and into central Missouri.

The timing of the incoming shortwave/lifting warm front has
remained a trickier part of the forecast, and convection south
along the cold front may also limit instability further
north/become the higher threat. At this time a Slight Risk was not
raised but may be needed with future updates.

Campbell/Tate
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 310757
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
357 AM EDT Tue Mar 31 2026

Day 1
Valid 12Z Tue Mar 31 2026 - 12Z Wed Apr 01 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
WESTERN NEW YORK AND SOUTHEAST MICHIGAN...

Overall upper pattern will become slowly backed as a deep longwave
trough out west begins to pump the mid-level ridge downstream from
the Mississippi River to the eastern CONUS. At the surface, a
quasi-stationary front will bisect areas west to east from the
Midwest the Northeast with a weak surface low migrating along the
frontal positioning. Shortwave associated with the area of low
pressure will eject through the Great Lakes leading to a period of
convective development downstream into Michigan and points east.
This initial round is expected to occur early in the period,
producing moderate to locally heavy amounts across southeast
Michigan and to the favored downwind locations of Lake Erie. The
extra enhancement from Lake Erie should boost rainfall closer to 2 inches.

As the morning progresses, the low will migrate into Ontario and
the frontal boundary will drop southward toward the Ohio Valley. A
second shortwave is set to eject and usher in another round of
convection for the northern Missouri Valley. PW values will be
increasing which should boost rainfall rates to 1-1.5 inches/hour.
These two rounds of heavy rain for western New York areas downwind
of Lake Erie will see widespread totals of 1.5-3" leading to a
more elevated flash flood concerns, especially when combined with
river flood concerns as stream flows across the region have been
elevated since the previous events over the area. Flood Watches
will be in effect for portions of western NY given the signal of
both the river and flash flood threat aligning well with a targeted
SLGT risk across the area.

The Slight Risk extends back into Detroit due to the urbanization
factors and expected heavy rainfall the front half the period into
the metro which creates a better opportunity for flash flooding
considering the setup. A Marginal Risk encompasses the
northeastern portion of Illinois through southern Michigan,
northern Indiana/Ohio, and extends well east and northeast to
include Upstate New York, Northern New England, and the northern
Hudson Valley as combination rainfall and snow melt will allow for
elevated stream flows and any locally heavy rainfall could induce
flash flood prospects.

Campbell/Kleebauer


Day 2
Valid 12Z Wed Apr 01 2026 - 12Z Thu Apr 02 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL STRETCHING FROM
EASTERN KANSAS INTO SOUTHEAST IOWA...

The latest guidance continued to trend westward with the overall QPF
footprint however maintained consensus for the heaviest amounts to
focus from eastern Kansas to the Missouri/Iowa border. A long axis
of convection is expected from Texas into the Mid/Upper Mississippi
Valley. A prominent warm-sector will materialize from west-
central Texas into Missouri with a surface low forecast to be
positioned over the Central Plains by Wednesday afternoon. Several
shortwaves will eject northeast within and ahead of the mean
trough leading to multiple waves of rainfall across parts of Kansas
into Missouri. Multiple waves of heavier rain could impact the
area. Despite the antecedent dry conditions in place, prolonged
rainfall within the urban corridor with slower cell motions could
lead to a greater threat for scattered flash flooding before the
system finally moves eastward and the area sees the frontal
passage. Areal averages of 1.5-2.5 inches are forecast however
there is potential for isolated higher amounts of 3+ inches. A
Marginal Risk area spans from central Texas to the Illinois/Indiana
border. A Slight Risk area was hoisted for eastern Kansas,
western/northern Missouri and southeast Iowa.

Campbell/Kleebauer


Day 3
Valid 12Z Thu Apr 02 2026 - 12Z Fri Apr 03 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
ILLINOIS, WISCONSIN AND LOWER MICHIGAN...

By this period the surface low pressure/frontal system will stretch
from the Mid-Atlantic back into the Ohio and Mid-Mississippi
Valleys. Models have trended further north with the overall
precipitation shield, now covering much of the Upper Great
Lakes/Upper Midwest region. The moisture and instability along
with the upper-level support could lead to flooding concerns across
parts of the Great Lakes region. Colder air filtering across the
northern tier will allow for wintry weather concerns in the Great
Lakes to Interior Northeast thus limiting the area where flash
flooding may occur/cause impacts. A swath of potentially impactful
freezing rain/ice along with multiple inches of April snow, with
the heaviest snow currently forecast in the U.P. of Michigan into
northern Maine. Some areas could see transitioning precipitation
types throughout the event. A Marginal Risk area is in effect for
portions of southern Wisconsin, Lower Michigan and northern Illinois.

Campbell
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 010803
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
403 AM EDT Wed Apr 1 2026

Day 1
Valid 12Z Wed Apr 01 2026 - 12Z Thu Apr 02 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL STRETCHING FROM
CENTRAL OKLAHOMA INTO NORTHERN MISSOURI...

The latest hi-res and global guidance noted a south/southwest-ward
shift of the axis of highest precipitation to central Oklahoma to
northern Missouri from its previous position of northeast Kansas
into east-central Iowa where areal averages of 1 to 3 inches are
expected. There remains a decent signal for localized 3+ inches in
the vicinity of the Topeka-Kansas City metros. The Slight Risk
area was adjusted to now cover eastern Oklahoma to northern
Missouri while the Marginal Risk was maintained from the Texas
Hill Country to the Mississippi/Ohio Valleys.

A prominent warm-sector will materialize from west-central Texas
into Missouri with a surface low forecast to be positioned over the
Central Plains by Wednesday afternoon. Several shortwaves will
eject northeast within and ahead of the mean trough leading to
multiple waves of rainfall from the south-central Plains into the
Middle Mississippi Valley. Some training potential, leading to 1-3
inch areal average amounts in this region, with some potential for
isolated higher amounts of 3+ inches. Farther south, a long axis
of convection is expected from Texas to Kansas along the cold
front, but storms in this area should be more progressive and soils
are even more dry than to the north.

Campbell/Santorelli


Day 2
Valid 12Z Thu Apr 02 2026 - 12Z Fri Apr 03 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN IOWA, NORTHERN ILLINOIS, WISCONSIN AND MICHIGAN...

The front will span from the Mid-Atlantic back into the Ohio and Mid-Mississippi Valleys during this period. Models have persisted
in placing the precipitation shield over much of the Upper Great
Lakes/Upper Midwest region. The moisture and instability along with
the upper-level support could lead to flooding concerns across
parts of the Great Lakes region. Colder air filtering across the
northern tier will allow for wintry weather concerns in the Great
Lakes to Interior Northeast thus limiting the area where flash
flooding may occur/cause impacts. Some areas could see
transitioning precipitation types throughout the event. A Marginal
Risk area remains in effect for portions of southern Wisconsin,
Lower Michigan and northern Illinois where precipitation is most
likely to stay mostly/all rain.

Campbell/Santorelli


Day 3
Valid 12Z Fri Apr 03 2026 - 12Z Sat Apr 04 2026

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN/CENTRAL PLAINS...

Strong to severe thunderstorms along with embedded heavy rainfall
will track across the Southern/Central Plains into the Midwest
during this period. Moisture (with PWs over the 90th, perhaps 95th
percentile) and instability are likely to pool along and ahead of
the associated cold front and produce widespread convection.
Storms likely beginning in the afternoon are expected to get
reinforced through the evening and night hours as a low level jet
picks up ahead of the cold front. A Slight Risk was maintained and
adjusted to span from northern Texas to southwest Missouri.

Campbell

$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 011552
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1152 AM EDT Wed Apr 1 2026

Day 1
Valid 16Z Wed Apr 01 2026 - 12Z Thu Apr 02 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL STRETCHING FROM
CENTRAL OKLAHOMA INTO NORTHERN MISSOURI AND THE CONCHO VALLEY...

...Central to Southern Plains...

16Z Update: The previous forecast remains on track with a heavy QPF
signature focused within the warm sector of a maturing synoptic
pattern as a lee surface low migrates eastward through the Central
Plains. Latest 12z HREF neighborhood probabilities for >3" remain
very elevated (50-70%) across areas of southeast KS up into
west-central MO, coincident with the axis of greatest convergence
where a propagating cold front will couple with a budding LLJ and
maximized mid-level forcing to create a solid area of heavy
convection beginning this afternoon, carrying through the overnight
hours. Heavy rain signature remains most prominent between the
quadrant of I-35/44/49/70 with portions of both the Wichita and
Kansas City metros in mix for heavy precipitation. Backed flow for
a time across zone will allow for some training elements prior to
the precip field migrating east-northeastward as a frontal passage
finally puts an end to the setup. Overall, this setup has
relatively good continuity in guidance going back to a few days
ago, thus only minor adjustments were made to the overall SLGT risk
area with the "biggest" change being more of an extension eastward
through MO for areas along and north of I-70 to correlate with some
overlap of heavy precipitation over areas that saw heavy rainfall
the past 12hrs.

Kleebauer

..Previous Forecast Discussion..

The latest hi-res and global guidance noted a south/southwest-ward
shift of the axis of highest precipitation to central Oklahoma to
northern Missouri from its previous position of northeast Kansas
into east-central Iowa where areal averages of 1 to 3 inches are
expected. There remains a decent signal for localized 3+ inches in
the vicinity of the Topeka-Kansas City metros. The Slight Risk
area was adjusted to now cover eastern Oklahoma to northern
Missouri while the Marginal Risk was maintained from the Texas
Hill Country to the Mississippi/Ohio Valleys.

A prominent warm-sector will materialize from west-central Texas
into Missouri with a surface low forecast to be positioned over the
Central Plains by Wednesday afternoon. Several shortwaves will
eject northeast within and ahead of the mean trough leading to
multiple waves of rainfall from the south-central Plains into the
Middle Mississippi Valley. Some training potential, leading to 1-3
inch areal average amounts in this region, with some potential for
isolated higher amounts of 3+ inches. Farther south, a long axis
of convection is expected from Texas to Kansas along the cold
front, but storms in this area should be more progressive and soils
are even more dry than to the north.

Campbell/Santorelli

...Texas...

A SLGT risk was added across the Concho Valley in west TX as trends
for back-building convection along a well-established dryline will
open the door for heavy precipitation totals where training
convection is plausible. Recent HREF QPF trends were pretty
substantial in the last few cycles of the hi-res ensemble with the
blended mean QPF a solid 2-3" across the area between the Lower
Trans Pecos and points east-northeast to the northern fringes of
Hill Country. A lot of this setup stems from a sharpening dryline
that tilts back to the west-southwest as a maturing nocturnal LLJ
takes shape after 23z. Convergent signature within a favorably
unstable environment and stout 45-55kt bulk shear axis should allow
for the initiation of supercellular convective modes the first 2-4
hrs of any development followed by an eventual merger of cells as
the LLJ matures further. This is a classic scenario of the southern
edge of a larger ascent pattern in spring that tends to be more
appreciable for heavy rainfall with the dryline and LLJ convergence
zone becoming the focal point for where the higher QPF concerns
arise. Latest HREF neighborhood probabilities for >3" of rainfall
are between 40-60% with the bullseye centered over the Concho
Valley, including the San Angelo area where terrain and
urbanization factors lend credence to a better localized flash
flood risk for the area of interest. Hourly rate probabilities for

1"/hr are very high (50-70%) for several hours across the same

area(s) which will be the driving force for the entire setup. In
coordination with the local San Angelo WFO, the SLGT risk was added
due to the evolving threat.

Kleebauer


Day 2
Valid 12Z Thu Apr 02 2026 - 12Z Fri Apr 03 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
EASTERN IOWA, NORTHERN ILLINOIS, WISCONSIN AND MICHIGAN...

The front will span from the Mid-Atlantic back into the Ohio and Mid-Mississippi Valleys during this period. Models have persisted
in placing the precipitation shield over much of the Upper Great
Lakes/Upper Midwest region. The moisture and instability along with
the upper-level support could lead to flooding concerns across
parts of the Great Lakes region. Colder air filtering across the
northern tier will allow for wintry weather concerns in the Great
Lakes to Interior Northeast thus limiting the area where flash
flooding may occur/cause impacts. Some areas could see
transitioning precipitation types throughout the event. A Marginal
Risk area remains in effect for portions of southern Wisconsin,
Lower Michigan and northern Illinois where precipitation is most
likely to stay mostly/all rain.

Campbell/Santorelli


Day 3
Valid 12Z Fri Apr 03 2026 - 12Z Sat Apr 04 2026

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTHERN/CENTRAL PLAINS...

Strong to severe thunderstorms along with embedded heavy rainfall
will track across the Southern/Central Plains into the Midwest
during this period. Moisture (with PWs over the 90th, perhaps 95th
percentile) and instability are likely to pool along and ahead of
the associated cold front and produce widespread convection.
Storms likely beginning in the afternoon are expected to get
reinforced through the evening and night hours as a low level jet
picks up ahead of the cold front. A Slight Risk was maintained and
adjusted to span from northern Texas to southwest Missouri.

Campbell

$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 040827
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
427 AM EDT Sat Apr 4 2026

Day 1
Valid 12Z Sat Apr 04 2026 - 12Z Sun Apr 05 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE ARKLATEX/LOWER MISSISSIPPI VALLEY AND A PORTION OF THE
SOUTHERN GREAT LAKES...

Much of convective evolution today depends on details about how
much convection lingers and exactly where the convection is located
this morning across Arkansas and Texas. East-northeastward
progression of a mid-level wave toward the Great Lakes will aid in southeastward movement of a cold front into the ARKLATEX and Lower
Mississippi Valley Eventually, the front will oriented more
parallel to weakening flow aloft supporting additional
opportunities for training convection as storms organize along
remnant outflows and backbuild, with the potential for areal
average rainfall in the 1-2" range leading to isolated instances of
flash flooding.

Maintained the Slight Risk area over portions of Texas and Arkansas
ahead of convection moving out of Oklahoma and northern Texas from
overnight prior of the start of the Day 1 period at 12Z Saturday.
Surface analysis showed a wave of low pressure along the front in
northeast Texas will also help to maintain/enhance the development
of this convection as well as briefly slow the progression of the
front northeast through the ArkLaTex, allowing for heavier rainfall
totals as storms persist over the region for a longer amount of
time before the front begins to sweep southward faster later into
the afternoon.

Also maintained the separate Slight Risk area to the east over portions
of the Lower Mississippi Valley later today as moist southerly flow
from the Gulf taps a pool of ~70 degree dewpoints and draws that
airmass northward. These high dewpoints along with daytime heating
will lead to a region of 1000-2000 J/KG CAPE supporting the
development of heavy- rainfall producing thunderstorms ahead of the
front. The combination of this initial development in addition to
a second round of storms expected along the front with similarly
high rain rates of ~2" per hour will also lead to the potential of
locally heavier totals in the 3-4" range. While dry antecedent
conditions/high FFGs may limit the overall threat, the potential
for these higher rain rates/totals within the highlighted Slight
Risks should be sufficient enough for at least a localized/urban
scattered flash flood threat.

Farther north, introduced a Slight risk area over portions of
northern Ohio and northern Indiana due to a combination of locally
heavy rainfall overnight falling on areas where the 1-hour flash
flood guidance was locally as low as 1 inch and the approach of a
front from the west which will potentially act to focus another
round of showers and thunderstorms. Rainfall rates are not likely
to be all that impressive nor will the duration of the rainfall be
particularly long due to the progressive nature of the front and
the strengthening flow aloft. Even so...recent rainfall has made
the area more susceptible to problems with flooding and run-off.

Bann


Day 2
Valid 12Z Sun Apr 05 2026 - 12Z Mon Apr 06 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF SOUTH TEXAS ON SUNDAY...

Much like model runs over the past day or two...the suite of
numerical guidance from 04/00Z has continued to trend a bit faster
with the arrival of a cold front from the north. This adds to the
concern that moisture and instability will be swept out of the area
very early in the Day 2 period...if not before the period begins at
12Z on Sunday. Spaghetti plots of QPF continue to show enough
members with post-frontal amounts in the 1 inch to 2 inch range to
keep the Marginal in place...but the area continued to be
increasing confined to coastal areas and the deep south portion of Texas.

Bann


Day 3
Valid 12Z Mon Apr 06 2026 - 12Z Tue Apr 07 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Bann
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 060830
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
430 AM EDT Wed May 6 2026

Day 1
Valid 12Z Wed May 06 2026 - 12Z Thu May 07 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE INTERIOR SOUTHEAST...

On-going convection at the start of the Day 1 period will linger
over portions of Arkansas. northern Mississippi and adjacent
portions of Tennessee as a cold front progresses into a most and
unstable atmosphere. Given the alignment of the storm motion and
the boundary...some training will continue with localized rainfall
totals of 1 to 2 inches before convection wanes. WPC Mesoscale
Precipitation Discussion was issued covering this area valid
through 1320Z.

The high-resolution guidance continued to struggle at eh 06/00Z
production cycle and continued with their earlier idea of bimodal
distribution to the heavy rainfall while coarser scale models
tended to have a more uniform distribution of rainfall but with
different orientations. Both the Latest HREF/RRFS guidance showed
some 15+ percent neighborhood probabilities of 24 hr QPF exceeding
10 year ARIs over portions of Mississippi and Alabama. This led to
a southward expansion of the Slight Risk area. Elsewhere...rainfall
amounts of 1 to 2 inches in an hour should be reachable within the
Slight Risk area but the signals as to where this happens are not
as strong. With increasing input from the convective allowing
models...further increases in expected rainfall amounts and better
agreement are possible which might result in an upgrade with future updates.

Bann


Day 2
Valid 12Z Thu May 07 2026 - 12Z Fri May 08 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
TEXAS EASTWARD TO GULF COAST REGION AND SOUTHEAST UNITED STATES...

Abundant moisture along a stalled frontal boundary on Thursday
will support additional thunderstorm formation along the front.
Rapidly weakening forcing at the surface and aloft will greatly
diminish convective coverage and restrict the parameters favorable
for heavy to excessive rainfall along the Gulf Coast and into
central Georgia and South Carolina. Given differences in the way
numerical guidance has in terms of how fast the front is
progressing...there was some continued adjustments to the placement
of the Marginal risk area.

South TX Brush Country...

An upper low with an associated surface boundary approaching the
region should lead to increasing chances for showers and
thunderstorms. Expectations are that most of the convection in this
time frame will remain west of the international border but there
are enough models showing some storms making east of the Rio Grande
River with isolated heavier amounts and inferred rainfall rates
that could lead to isolated flooding concerns during the late day/evening.

Bann


Day 3
Valid 12Z Fri May 08 2026 - 12Z Sat May 09 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE LOWER- AND CENTRAL TEXAS COAST ON FRIDAY...

Attention shifts to the Lower Texas coast for a risk of excessive
rainfall as shortwave energy nears the region from the southern
Great Basin and northern Mexico. Low level flow backs in response
to the approaching shortwave which results in precipitable water
values to exceed 2 inches along the immediate coastline. This
occurs at the same time flow aloft is expected to become
increasingly difluent and when the CAPE is approaching 1000 J per
kg. This should result in growing coverage of convection that will
be capable of producing rainfall rates sufficiently high to result
in isolated instances of flash flooding.

Bann

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE GULF COAST AND SOUTHEAST UNITED STATES...

The risk of excessive rainfall will be focused along the low-level
boundary that builds into the region on Day 2 and stalls along a
west to east axis. Precipitable water values in excessive of 1.5
inches should be pooling along the boundary on Friday...with higher precipitable water values returning northward later in the day on
Friday and through Friday night/early Saturday morning.

Southern stream shortwave energy become southerly during the day
and increases.

The Marginal risk area is conditional in the sense that a Slight
could be needed depending on observed rainfall on Day 2, the
degree of overlap with Day 3 QPF and the amount of urbanization.

Bann
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 070810
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
410 AM EDT Thu May 7 2026

Day 1
Valid 12Z Thu May 07 2026 - 12Z Fri May 08 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM SOUTHERN
ALABAMA AND THE FLORIDA PANHANDLE TO SOUTHERN GEORGIA...

...Gulf Coast/Southeast...
While the overall coverage and intensity will likely be
diminishing, showers and storms will remain ongoing with the
potential for additional heavy amounts and flash flooding concerns
beyond 12Z this morning. A Marginal Risk was maintained across
portions of southern Alabama, the Florida Panhandle, and southern
Georgia. A 40-50 kt southwesterly low level jet ahead of an
approaching front will continue to support PWs around 2 inches,
which along with favorable upper jet forcing will likely support
the continuation of some storms with heavy rainfall rates well into
the morning. Both the HREF and RRFS indicate that localized
additional amounts of 1-2+ inches are likely. This is expected to
occur mostly, if not entirely, within the first 6 hours of the
period before the deepest moisture and the better forcing moves downstream.

...Rio Grande Valley...
The Marginal Risk has been removed. While a weak surface low and
approaching shortwave trough will support convective development
over the mountains of Mexico, the majority of the models indicate
that the bulk of the heavy rainfall will remain south of the
international border. While an isolated heavy total remains
possible, and the threat for flash flooding across South Texas is
non-zero, the coverage is no longer expected to meet Marginal Risk criteria.

Pereira


Day 2
Valid 12Z Fri May 08 2026 - 12Z Sat May 09 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM SOUTH TEXAS
GULF COAST THROUGH THE LOWER MISSISSIPPI VALLEY...

The synoptic pattern on Friday will characterized by the return of
deep moisture as a previously stalled front, lingering along the
Gulf Coast begins to lift northward as a warm front. PWs are
forecast to climb above 1.75 inches from South Texas through the
lower Mississippi Valley, providing an ample reservoir for heavy
rainfall. This moisture, along with an upper level low moving into
West Texas and downstream shortwave energy/upper jet forcing, are
expected to support numerous showers and storms with the potential
for heavy rates. However, while the environment is expected to be
favorable for numerous showers and storms to develop, confidence in
the placement of the heaviest rainfall has diminished with this
cycle, with significant model spread regarding where the most
intense convective clusters will organize. Therefore, the Slight
Risk that was previously carried from southeastern Texas through
the lower Mississippi Valley has been removed for now. The
reintroduction of a Slight Risk may be warranted in future updates, particularly farther southwest across South Texas closer to the
ejecting upper low/shortwave, but predictability is too low to
maintain the higher category. For now, will maintain a broad
Marginal Risk extending from South Texas to southern Mississippi.

Pereira


Day 3
Valid 12Z Sat May 09 2026 - 12Z Sun May 10 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PARTS OF
THE LOWER MISSISSIPPI VALLEY AND THE CENTRAL GULF COAST...

The previously noted upper level low moving across southern Texas
on Day 2 will continue to eject east, moving along the central Gulf
Coast into the Southeast -- deamplifying as it becomes embedded
within the base of a broad upper trough centered over the central-
eastern U.S. Deep moisture remaining ahead of this wave and along a
slow-moving boundary will continue to fuel shower and storm
development capable of producing heavy rainfall. Similar to Day 2,
confidence was lacking for any upgrades beyond a Marginal Risk.
However, should the models start to move into better agreement, an
upgrade may be warranted in future updates -- especially if the
guidance begins to show a growing signal for heavy amounts across
areas impacted by recent heavy rains.

Pereira
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 080800
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Fri May 8 2026

Day 1
Valid 12Z Fri May 08 2026 - 12Z Sat May 09 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
SOUTHEASTERN LOUISIANA AND SOUTHERN MISSISSIPPI...

...Lower Mississippi Valley/Central Gulf Coast...
A robust moisture pool is expected to deepen along the central Gulf
Coast today as southwesterly winds amplify ahead of energy moving
out of eastern Texas and the northwestern Gulf. This flow will
support PWs climbing to around 2 inches along a slow-moving front,
or more than 2.5 std dev above normal. The majority of the CAMs
are in good agreement indicating a corridor of training convection
developing by the afternoon across southeastern Louisiana and
southern Mississippi. Given the high moisture content and potential
for training, localized totals of 2-3+ inches are possible. High
hourly rates within these training storms will pose a risk for
flash flooding, particularly in low-lying and urban areas, with
the highest potential impact centered along the I-10 corridor. The
introduced Slight Risk area reflects high neighborhood
probabilities shown by both the HREF and RRFS for amounts exceeding 2 inches.

...South Texas...
Farther west, a well-defined mid-to-upper level shortwave/low
moving through northern Mexico into West Texas will provide
increasing ascent. Moist southerly flow interacting with this
feature and upslope into the Sierra Madre Oriental will support
storms developing over northeastern Mexico. While much of this
activity may remain south of the international border, there are
some hi-res members that show some of these convective clusters
moving into South Texas. Though model spread is higher in this
region, both the HREF and RRFS indicate that localized totals
exceeding 2 inches are possible. Therefore, a Marginal Risk was
maintained to account for this potential.

Pereira


Day 2
Valid 12Z Sat May 09 2026 - 12Z Sun May 10 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE CENTRAL
GULF COAST INTO THE SOUTHEAST...

The previously noted shortwave moving into West Texas on Day 1 is
forecast to move eastward along the central Gulf Coast on Saturday.
While lingering deep moisture will remain in place, the synoptic
signal for organized and widespread heavy rainfall becomes
significantly more diffuse. Current model guidance lacks a
concentrated signal for high-end totals, suggesting a more isolated
or low-end flash flood threat. Given the environment and the
potential for antecedent conditions driven the previous day's heavy
rains, the current Marginal Risk was maintained for this cycle. But
should model trends continue to show a lack of organization, this
area may be discontinued in future updates.

Pereira


Day 3
Valid 12Z Sun May 10 2026 - 12Z Mon May 11 2026

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS
OF NORTHEASTERN TEXAS, SOUTHEASTERN OKLAHOMA, SOUTHERN ARKANSAS,
AND NORTHERN LOUISIANA...

Shortwave energy diving into the base of broader scale trough will
drive a cold front southward across the region. Southerly flow
ahead of the boundary will boost PWs to over 1.5 inches. This
moisture, combined with favorable upper jet forcing, will support
storms developing along and ahead of the front. While model spread
is currently too high to support a higher risk area and the signal
for widespread heavy totals remains muted, locally intense rates
along with some areas of repeating cells could result in isolated
flash flooding.

Pereira
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 150736
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
336 AM EDT Fri May 15 2026

Day 1
Valid 12Z Fri May 15 2026 - 12Z Sat May 16 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Wegman


Day 2
Valid 12Z Sat May 16 2026 - 12Z Sun May 17 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Convection developing along a warm front draped across the Ohio
Valley could form over more sensitive urban areas on Saturday
afternoon. Soils across the Ohio Valley have sufficiently dried out
from the last round of organized heavy rain, so any flood threat
would likely be tied to the urban areas. The CAMs that cover this
time period are mostly suggesting any convection will quickly
develop into fast-moving line segments. Further, where those line
segments form is highly uncertain. Thus, the area will be monitored
for a potential future Marginal Risk, but for now uncertainty is
too great to draw one in at this time.

Wegman


Day 3
Valid 12Z Sun May 17 2026 - 12Z Mon May 18 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE UPPER MIDWEST/UPPER MISSISSIPPI VALLEY...

A digging longwave upper level trough will eject several rounds of
shortwave energy northeastward ahead of the trough from the central
Plains and into the Upper Midwest on Sunday. The nose of a stout
low-level jet will provide ample moisture for any storms that
develop to feed on. Morning rain will douse the area as the dying
remnants of an MCS move across the Marginal Risk area. There will
likely be a break in any rainfall for much of the day as the
atmosphere recharges and instability advects north ahead of an
approaching area of low pressure. Numerous showers and
thunderstorms will form in a line very late in the day, near
sunset, with the storms moving sufficiently parallel/along the line
to introduce a training threat across the Marginal Risk area. Much
of the heaviest rain and the greatest flash flooding threat will
occur Sunday evening before the surface low pressure propagates
into Minnesota and allows the convection to have a faster push
towards the east. The increasing forward speed of the line will
diminish the flooding threat somewhat after midnight, through
convection ahead of the low could still affect portions of northern
Minnesota well into the overnight. Dry antecedent soil conditions
should generally mitigate the flooding risk, so the inherited
Marginal Risk was left largely unchanged. Some trimming on both the
west and east sides were done to highlight the increasing
confidence that the axis of heaviest rainfall will occur generally
across Minnesota, potentially spilling over to adjacent areas of
the neighboring states.

Wegman
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 160737
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
337 AM EDT Sat May 16 2026

Day 1
Valid 12Z Sat May 16 2026 - 12Z Sun May 17 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE LOWER TO MID OHIO VALLEY AS WELL AS PORTIONS OF THE CENTRAL PLAINS...

...Lower to Mid Ohio Valley...

Areas of convection that will form along a warm front at the nose
of a low-level jet are expected to develop during peak heating
today across the lower to mid Ohio Valley. While the main branch of
the low level jet remains oriented south to north over the Plains,
the side branch over the Ohio Valley will be oriented southwest to
northeast. This will promote training storms with backbuilding
convection, while the primary storm movement is towards the
east. Training storms are most likely to develop in the Marginal
Risk area. Despite very dry soils over the region, which will limit
the flash flooding risk, some urban areas are threatened with the
possibility of training storms, so the Marginal remains in place.

...Central Plains...

During the early evening hours, showers and thunderstorms will
develop along the nose of a robust low level jet transporting
abundant moisture and instability north from the Gulf into the
central Plains. A warm front at the leading edge of the warm, moist
air mass will interact with a strengthening upper level shortwave
and a developing surface low over southwest Kansas to support the
convective activity. While some of the convection will develop into
a highly progressive bowing segment, it's likely that the southern
end of the bow will get "stuck" and remain largely in place as
additional convection backbuilds westward, generally along the
Iowa/Missouri border. Repeating rounds of convection are possible,
and likely to be of somewhat greater vigor than the ongoing
convection across Iowa. Any overlap of the convection this evening
with the rainfall footprint of the ongoing storms present over
central Iowa could also locally increase the flash flooding risk.
However, at the moment any overlap should be minimal, as the
strongest storms with the greatest flash flooding risk are expected
along the Missouri/Iowa border, which did not see any meaningful
rain last night. Thus, the Marginal remains in place as soils in
the region remain very dry.

...Elsewhere...

In between the areas of storms over eastern Missouri/western
Illinois, a "break" is likely to remain, separating the footprints
of the two areas of storms. With minimal rainfall expected along
the Mississippi River near St. Louis, the inherited Marginal was
removed, leaving two separate Marginal Risk areas.

Wegman


Day 2
Valid 12Z Sun May 17 2026 - 12Z Mon May 18 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE UPPER MIDWEST...

A robust low level jet feeding plentiful moisture ahead of a
developing low over the Plains will provide the moisture and
instability needed for numerous thunderstorms across a large
portion of the upper Midwest from far eastern Nebraska northeast
through the Arrowhead of Minnesota. The storms are likely to be
their strongest Sunday night. This will coincide with the diurnal
strengthening of the low level jet. Clusters of showers and storms
will develop with increasing forcing ahead of a slow moving upper
level trough over the High Plains. The storms are likely to train
as several rounds of upper level energy support several rounds of
storm clusters. Much of Iowa saw beneficial rains overnight
tonight, such that by Sunday night, the soils will still have some
moisture left over. Urban concerns, especially in and around the
Twin Cities could also locally increase the flash flooding threat.
Significant dry time in between the storms should limit the
flooding threat such that the inherited Marginal still looks good,
and few changes were needed.

Wegman


Day 3
Valid 12Z Mon May 18 2026 - 12Z Tue May 19 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM PORTIONS OF
THE CENTRAL PLAINS THROUGH THE UPPER MIDWEST...

An upper level trough that has been "stuck" over the northern High
Plains for a few days will finally begin to eject across the
northern Plains on Monday. This will occur because a strong
shortwave on its southern edge near the 4 Corners region will help
to nudge the trough eastward. This strong shortwave will run into
plentiful Gulf moisture that will continue streaming northward
across the middle of the country, as it has been doing for the past
several days. A cold front on the northwestern boundary of that low
level jet will provide ample surface forcing for the storms. The
initial meeting of the warm, moist air mass to the east and the
cooler, drier air mass over the northern Plains will be along the
Missouri River from far northeastern Kansas north across much of
western Iowa. This will be the corridor where the heaviest rainfall
totals are expected on Monday through Monday night. This is the
same region that will have been hit by multiple days of scattered
heavy rainfall. By Day 3/Monday, soils should be much closer to
saturation. Thus, with the greatest rainfall amounts areally
expected on Monday, the flooding threat increases into the Slight
Risk category. Any storms that form will continue to rapidly
progress northeastward into the upper Mississippi Valley. This area
too will have seen multiple days of storms by Monday. Thus,
expecting wetter than normal soil conditions in most areas by
Monday, the Slight Risk area was expanded northward to cover the
upper Mississippi Valley to the western tip of Lake Superior.

There remains some uncertainty as to where the axis of heaviest
rainfall will set up. Thus, the surrounding Marginal covers
extensive real estate east of the Slight from northern Illinois
north through much of the U.P. of Michigan. While expected rainfall
totals are lower in this region, greater urban concerns are present
in this area, which supports the Marginal Risk.

Wegman
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 170703
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
303 AM EDT Sun May 17 2026

Day 1
Valid 12Z Sun May 17 2026 - 12Z Mon May 18 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE CENTRAL PLAINS TO THE UPPER MIDWEST...

A pair of shortwave troughs tracking northeast on the downwind side
of a slow moving longwave trough over the Intermountain West will
provide upper level forcing for several rounds of thunderstorms to
impact a large area from Kansas through the upper Great Lakes. A
fully open Gulf and associated moisture plume will continue to
advect northward up the Plains and Mississippi River. This will
keep PWATs consistently above 1.25 inches, with many areas above
1.5 inches. This influx of moisture will support and instability
will support both storms capable of heavy rainfall, as well as
development and redevelopment of storms in this favorable weather
regime. For the most part, due to fast upper level flow, the storms
will likely organize into fast moving lines/segments, which should
work to keep rainfall totals manageable in any one area. The
greatest area of concern stretches from southeastern Nebraska east
along the Iowa/Missouri border, where multiple inches of rain have
fallen overnight last night. Thus, any backbuilding or holdups in
any lines of storms could have outsized flooding impacts. A short-
fused Slight may be needed once again in this general area if
rainfall totals today come up further.

For southeastern Louisiana, the inherited MRGL was removed. Nearly
all of the guidance shows only light showers expected to impact
that area, with only a one or two showing one isolated storm.
Further, high FFGs should preclude any flooding even if that one
storm does form.

Wegman


Day 2
Valid 12Z Mon May 18 2026 - 12Z Tue May 19 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM THE CENTRAL
PLAINS TO THE UPPER MISSISSIPPI VALLEY...

Relatively few changes were needed to the outlook for this likely
busiest day of the upcoming three. A strong shortwave making up the
base of the longwave trough over the Rockies will finally eject out
over the Plains on Monday. As that shortwave interacts with
plentiful Gulf moisture streaming north up the Plains, renewed
lines of showers and storms are expected to develop across the
Slight Risk area. Since the storm motion will be towards the
northeast, largely parallel to the moisture and instability plume
emanating from the Gulf, backbuilding will be a greater
possibility than in previous days. Several of the high resolution
model guidance show that there could be multiple rounds of storms
to impact the area from northeast Kansas through southwestern Iowa,
especially in the late afternoon through the first half of the
overnight. This area is currently getting very hard-hit with heavy
rain from a very slow-moving MCS that has been producing multiple
inch per hour rainfall rates and numerous instances of flash
flooding. Thus, the soils have become very saturated in some areas.
Following potential heavy rain during the day 1/Sunday period,
much more rain is expected in this region again on Monday. A
higher-end Slight covers the aforementioned region from northeast
Kansas through the southwest corner of Iowa. Should multiple inch
per hour rates materialize again in this same region, a Moderate
Risk upgrade will need to be considered with future updates.

Wegman


Day 3
Valid 12Z Tue May 19 2026 - 12Z Wed May 20 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE SOUTHERN
PLAINS THROUGH THE LOWER OHIO VALLEY...

The inherited Slight Risk for the southeastern half of Oklahoma was
removed with this update. Guidance has been understandably
struggling with the placement of expected rainfall/convection
across this region. Since there's excellent agreement that the axis
of heaviest rainfall will shift well south of the area expected to
be hit with heavy rain in days 1 and 2, the region of greatest
impact is an area where soils have dried out and will likely be
very receptive to beneficial rainfall. Since guidance is in poor
agreement on where the storms will be most persistent, instead
broad brushing much of the Marginal Risk area with anywhere from a
half inch to 1.25 inches, have opted to leave the large Marginal in
place. None of the guidance particularly favors southeastern
Oklahoma for any heavier amounts that anywhere else, especially
further south into Texas. Expect that should a new Slight be needed
with a future update, it will be over a portion and not into
Oklahoma, which sits at the back/northwestern edge of the heavier rain axis.

Wegman
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 310825
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
425 AM EDT Sun May 31 2026

Day 1
Valid 12Z Sun May 31 2026 - 12Z Mon Jun 01 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE NORTHERN ROCKIES AND THE SOUTHEAST UNITED STATES...

Northern Rockies...
With rainfall on-going from Saturday due to a slow moving mid- and
upper-level system over the northern Rockies...opted to keep
portions of Montana and nearby Wyoming and the far western Dakotas
in a Slight Risk area during the new Day 1 period. The expectation
is that rainfall intensities will not be as high as they were on
Saturday but the cumulative effect of an additional 1+ inch amounts
on top of what has already fallen has the potential to produce
flooding concerns today. The Slight risk area was extended into far
western South Dakota where MRMS showed 3+ inches having fallen on
Saturday evening and was susceptible to flooding from even modest
rainfall amounts.

Southeast US...
Also introduced a Slight Risk area over portions of the Southeast
US where some model agreement has developed...although the
agreement was far from unanimous. Neither the HREF or RRFS showed
a strong signal for exceedance of flash flood guidance but showed
about 20 percent neighborhood probabilities of rainfall exceeding 2
inches. At the same time...a spaghetti plot of SREF QPF showed
decent amount of ARW members with QPF at 2 inch and 3 inch amounts.
That was largely supported by the GEFS. Given the 2 to 2.25 inch
precipitable water values and the amount of instability in the area
that could support intense rainfall rates...opted to include a
Slight Risk at this point.

Elsewhere...maintained the broad and largely unfocused Marginal
Risk area in between given the lack of clear forcing mechanism, the
light flow aloft and the broad pool of instability along and south
of a quasi-stationary boundary.

Bann


Day 2
Valid 12Z Mon Jun 01 2026 - 12Z Tue Jun 02 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE NORTHERN ROCKIES AND PARTS OF THE PLAINS...

Northern Rockies...
Introduced a Marginal Risk area in the northern Rockies where moisture/precipitation lingers as a slow moving mid- and upper-
level system pulls away. The concern is not so much for rainfall
intensity at this point but for the cumulative effect of the
additional rain on top of what has fallen in the previous few days.
The concern is also fairly limited in terms of duration as
rainfall does come to an end during the middle- to latter-part of the period.

Western High Plains...
Also introduced a Marginal Risk area mainly in the western portion
of Kansas/Nebraska as an axis of low level moisture begins to
return northward during the day. Placement of the QPF and any
associated risk of excessive rainfall remains somewhat tenuous.
Concern is that the instability should be enough that the QPF
amounts approaching or exceeding 2 inches from the UKMET/NAM and
GFS would be delivered quickly. A

Southeast US...
Portions of the Mid-South/Southeast may also be at-risk for
Excessive Rainfall, but guidance remains murky on where storms will
initiate. Given these reasons, the Day 2 ERO remains free of risk
areas for the time being.

Mullinax/Bann


Day 3
Valid 12Z Tue Jun 02 2026 - 12Z Wed Jun 03 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
NEW MEXICO AND A SMALL PORTION OF WEST TEXAS...

A plume of Gulf-sourced moisture will be drawn northward into the
southern Rockies/drifting east over the southern High Plains/west
Texas to maintain a Slight Risk area for excessive rainfall on
Tuesday into Tuesday night from portions of New Mexico into west
Texas. Farther north...warm moist air will advect along a low
level convergence zone with early June heating that has the
potential for locally heavy rainfall over portions of the western
High Plains into the Dakotas.

Bann
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 010807
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
407 AM EDT Mon Jun 1 2026

Day 1
Valid 12Z Mon Jun 01 2026 - 12Z Tue Jun 02 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE NORTHERN ROCKIES, GREAT PLAINS, AND MID-SOUTH...

...Northern Rockies...
A closed mid-level system will continue to slowly move across
Montana during the period, bringing an additional 1 to 2 inches of
rainfall. The Marginal Risk for isolated / localized flooding was
maintained with minimal adjustments based on the 00Z guidance.

...Mid-South...
Early morning MCS across eastern Kansas and Missouri is expected
to continue to move east/southeast through this morning toward the
TN Valley and Mid-South. Forward propagation after 12Z should
overall limit widespread heavy rainfall, but some elements may
locally train/repeat over the same area bringing a risk of flash
flooding, particularly early in the period across eastern Missouri.
While that activity is likely to wane by late morning, additional
thunderstorms are expected to fire up along remnant outflow
boundaries to the south and west across Mississippi and Alabama.
Pockets of 1-2" in a short duration may result in isolated flooding,
with the overall threat maintained at the Marginal Risk level.

...Central Plains...
Broad upper level forcing across the region along with modest
southeasterly low level flow will bring isolated to scattered
diurnally driven convection today across the High Plains that will
gradually track eastward through south central Nebraska and western
to central Kansas into this evening and overnight. The Marginal
Risk was maintained with a few adjustments based on the latest
model guidance.

...West Texas into New Mexico...
Modest forcing for ascent across the region combined with low level southeasterly flow will bring westward Gulf moisture. Diurnal
convection is expected across the Davis and Sacramento Mtns. Based
on the 00Z hi-res models, some of this convection may spread away
from the terrain, but overall expected to be isolated in coverage
with a localized flash flood risk today.

Taylor


Day 2
Valid 12Z Tue Jun 02 2026 - 12Z Wed Jun 03 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
WEST TEXAS INTO NEW MEXICO...

...West Texas into New Mexico...
By Tuesday, the latest model guidance suggests greater moisture
will expand westward toward the region (compared to today) with PW
anomalies approaching 1.5 to 2 std deviations above normal. Another
round of terrain driven convection is expected that spreads east
across the area. Overall, pockets of 1 to 2 inches are possible
with resulting isolated/scattered flash flooding, particularly for
any sensitive locations such as burn scars and steeper terrain.

...Great Plains...
Large scale forcing for ascent across the High Plains will work
with an increasing amount of low level moisture to produce several
clusters of thunderstorms during the period capable of producing
heavy rainfall - one area of concern is across eastern to central
Kansas where the latest guidance has pointed toward the potential
for several repeating clusters of intense rain rates. Some of this
additional rainfall may fall on areas expected to see heavy
rainfall today. A second area of concern is the Northern Plains
where there is likely to be better forcing with the proximity to
the mid/upper level feature. Here, moisture isn't as high and storm
motions may be faster, but potential exists for intense rain rates
and locally heavy rainfall. Both of these areas (Dakotas and
western/central KS) may need upgrades to Slight Risk if trends
continue with future model cycles but for now, have maintained the
Marginal given some of the uncertainty heading into Tuesday.

...North Florida through the Gulf Coast...
A cold front will slowly advance southward across the region during
the day Tuesday, with copious amounts of moisture pooling along and
ahead of it. Thunderstorms are likely to develop, particularly
focused on the Florida Panhandle to northeast Florida where the
latest guidance points to the potential of 1-3" locally. Localized
/ isolated flash flooding will be possible due to the expected
intense rain rates and overall slower storm motions.

Taylor


Day 3
Valid 12Z Wed Jun 03 2026 - 12Z Thu Jun 04 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF WEST TEXAS...

...West Texas into New Mexico...
A greater signal exists for a stronger mid-level shortwave to move
across the southern High Plains on Wednesday. This feature,
combined with the continued relatively higher moisture in place,
should result in robust convection to develop across far eastern
New Mexico into western Texas, particularly across the TX Panhandle.
A Slight Risk was maintained for the potential of isolated to
scattered flash flooding, some of which may fall on similar areas as Tuesday.

...Great Plains...
The active pattern across the Plains is expected again on
Wednesday with a plume of relatively higher moisture extending from
Texas all the way north into the Northern Plains. Daytime
convection is expected to fire up across the Plains and then move east/southeast into the evening/overnight hours. Several organized
clusters of convection are likely with pockets of locally heavy
rainfall. For now, a broad Marginal Risk remains in place for
isolated instances of flash flooding.

Taylor
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 020809
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
409 AM EDT Tue Jun 2 2026

Day 1
Valid 12Z Tue Jun 02 2026 - 12Z Wed Jun 03 2026

...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
WEST TEXAS INTO NEW MEXICO AND NORTH DAKOTA...

...Dakotas...
A mid to upper level system and associated surface front will
approach the region during the period. Ahead of it, warm moist air
will expand across the area with the latest guidance showing
precipitable water values over 1.2" and by afternoon, MUCAPE values
in excess of 1000 J/kg. Deep convection firing up in the afternoon
will initially be more discrete but is expected to evolve into
linear segments as the evening commences with a ramp up late in the
period possible with the developing low-level jet.

The 00Z HREF shows the threat for rainfall totals in excess of 3"
across the Slight Risk area with the greatest potential across
central to northeastern ND (50-80 percent). Isolated maximum hourly
rainfall totals of 2 inches will be possible. For these reasons,
the Slight Risk for flash flooding looks appropriate and no
significant changes were made for this update.

...Eastern New Mexico into West Texas...
Another day of isolated to scattered thunderstorms across the
region is expected as moist southeasterly flow expands further
westward into eastern New Mexico. With cool temperatures aloft
given the baggy trough in place, this should be sufficient for
greater coverage of thunderstorms, initially tied to the terrain
and then moving eastward toward the NM/TX border. Peak hourly
rainfall totals in excess of 1 inch will be possible across eastern
NM and total amounts of 1" to locally 3" will be possible. The
Slight Risk is maintained for the potential of isolated to widely
scattered flash flooding particularly for sensitive areas like
burn scars and steeper terrain.

...Gulf Coast into South Florida...
A frontal boundary analyzed early this morning across the Gulf
Coast is expected to slowly drop southward through the period.
Along and ahead of this feature, precipitable water values range
from 1.5" to locally over 2", which is around 1.5 std above normal
for some locations. The frontal position, combined with a favorable
upper pattern, will provide the forcing for ascent today. With
expected instability values exceeding 1500 J/kg (MUCAPE) during
peak heating, scattered to numerous showers and thunderstorms are likely.

The latest HREF probabilities show potential for hourly rain
totals between 1-2" (up to 50 percent probability), peaking during
the afternoon to early evening hours. Totals of 1-3" are expected
within the risk area, with isolated totals of 3-5" possible in the strongest/slowest thunderstorms, most likely to occur across
portions of FL Panhandle and across South Florida. Isolated to
scattered instances of flash flooding are possible given the
potential for intense rain rates, particularly over sensitive
locations like urban corridors.

Taylor


Day 2
Valid 12Z Wed Jun 03 2026 - 12Z Thu Jun 04 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS WEST TEXAS
INTO NEW MEXICO...

...West Texas into New Mexico...
Weak troughing aloft and the remaining relatively higher moisture
in place across the region will likely promote the development of
isolated to scattered thunderstorms again on Wednesday. The focus
for the greatest concentration of thunderstorms and rainfall
totals will shift a bit further east this day, likely along the
NM/TX border into the TX Panhandle where amounts of 1-2" with
isolated 3" totals likely. Isolated to scattered instances of flash
flooding will be possible.

...Great Plains...
An axis of higher moisture will be present ahead of an advancing
cold front moving across the Northern Plains. Moist unstable air
ahead of it will promote the development of several clusters of
thunderstorms capable of producing intense rain rates between
1-2"/hr. Isolated to scattered flash flooding is anticipated with
a possible upgrade to a Slight Risk needed for parts of eastern ND
and far western MN if trends continue for a more concentrated area
of thunderstorms and heavy rainfall.


Day 3
Valid 12Z Thu Jun 04 2026 - 12Z Fri Jun 05 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE PLAINS, UPPER MIDWEST, AND TEXAS...

...Northern Plains into the Upper Midwest...
Shortwave energy ejects into the Plains during the period with the
frontal boundary expected to become increasingly west to east
oriented as it drapes across the Upper Midwest by Thursday. This
will allow the moisture to pool ahead of it while also creating a
more favorable setup for training/repeating thunderstorms that are
expected to develop during the peak heating and continue into the
overnight hours with the surging low level jet. While there
remains uncertainty on placement (north solutions versus some that
are further south), the ingredients appear to be in place for heavy
rainfall from portions of the Dakotas eastward toward Minnesota.
For now, a Marginal Risk remains in place but an upgrade to a
Slight Risk may be needed in future updates if trends continue for
a training thunderstorm scenario.

...Plains to Texas...
A mid to upper level system slowly moving east out of western
Mexico will approach the region during the period. As it does so,
it will continue to pull into the area copious amounts of Gulf
moisture. This will bring additional rounds of thunderstorms to the
area, some of which will be locally heavy given the PWs in place
and potential for repeating rounds. For now, will keep a Marginal
Risk in place, but if greater organization of storms or confidence
on specific areas rises, a Slight Risk may be needed for portions
of western to central Texas with future updates.

Taylor
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 030801
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
401 AM EDT Wed Jun 3 2026

Day 1
Valid 12Z Wed Jun 03 2026 - 12Z Thu Jun 04 2026

...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE NORTHERN PLAINS AND WEST TEXAS INTO EASTERN NEW MEXICO...

...Northern Plains...
Multiple areas of convection producing heavy rainfall and intense
rainfall are expected across portions of the eastern Dakotas into
far western Minnesota during the period. This activity is tied to
an advancing cold front with an axis of anomalous moisture along
and ahead of it. While the setup isn't the most favorable for training/backbuilding and generally favors more progressive storm
motions, the ingredients do support the latest HREF probabilities
for isolated totals in the 3-5" range. The Slight Risk was
minimally adjusted to the latest trends.

...Texas into Oklahoma...
A surface boundary in the vicinity of the area along with a feed
of Gulf moisture from the southeast will continue the unsettled
weather pattern. Convection is likely to be ongoing at the start of
the period across far eastern NM into western TX, capable of
producing locally heavy rainfall and rain rates between 1-2"/hr.
This activity may then subside by mid day. Convection is then
expected to blossom further to the northeast across the TX
Panhandle and west-central Oklahoma. The Slight Risk in that area
looks good and lines up well with the latest HREF probabilities
for 3 inches (50-70 percent) and 5 inches (25 percent).

...South Florida and the Keys...
Approaching frontal boundary and tropical moisture in place will
contribute to another day of higher coverage and intensity of
thunderstorms across portions of South Florida urban corridor. HREF probabilities are elevated for localized 3-5" totals (along with
hourly rain totals locally between 2-3") where thunderstorms
persist/repeat, so a Marginal Risk has been maintained. There is
some signal that the intense rain rates and heavy rainfall may
approach the entirety of the Keys, so have opted to expand the
Marginal through Key West.

Taylor


Day 2
Valid 12Z Thu Jun 04 2026 - 12Z Fri Jun 05 2026

...THERE ARE MARGINAL RISKS OF EXCESSIVE RAINFALL ACROSS THE
PLAINS TO THE UPPER MIDWEST AND SOUTH FLORIDA ...

...Plains to Upper Midwest...
The cold front is expected to set up across Minnesota into the
Plains during the period, acting as the focus for organized
convection. A ramp up in the low-level jet late in the period will
likely be the primary concern for training/repeating rounds of
heavy rainfall as daytime convection should be mainly progressive
and more discrete in nature. The deterministic guidance remains
disperse and ensemble probabilities low to provide confidence for
any upgrade to Slight Risk at this time, but areas from southwest
Minnesota into portions of Iowa and eastern South Dakota are of
concern. For now, the Marginal Risk was maintained and adjusted to
the latest trends, trimming some from the western to northern boundary.

Further south into the Plains and Texas, the continued moist
southeasterly flow and approaching mid level system out of Mexico
will bring a greater coverage of thunderstorms and the threat of
locally heavy rainfall. Overall organization of the convection is
expected to be on the lower side, but the PW anomalies support
potential for locally intense rain rates and the Marginal Risk.

...South Florida...
Frontal boundary stalling in the vicinity of the area will remain
the focus for scattered to numerous showers and thunderstorms
capable of producing intense rain rates and locally heavy rainfall
over the highly urbanized corridor. The risk for Thursday shifts a
bit further south across South Florida, mainly centering across the
Miami metro.

Taylor


Day 3
Valid 12Z Fri Jun 05 2026 - 12Z Sat Jun 06 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE PLAINS, UPPER MIDWEST, TEXAS, AND GULF COAST...

...Upper Midwest...
Low pressure moving across the region with its associated cold
front will be the focus for thunderstorm development Friday into
Friday night with southwesterly flow bringing in an axis of
relatively higher moisture. Aspects of this setup will favor
some training/repeating thunderstorms but the overall motion will
probably lean more progressive. If the front ends up more west to
east oriented and allows for a better setup for training, portions
of the area could need an upgrade to a Slight, but confidence on
that is too low at this point.

...Texas into Gulf Coast...
The mid/upper level feature over Mexico moves into Texas during
this period, continuing another day of generally unsettled weather
and scattered to numerous showers and thunderstorms. If deeper
instability can materialized, pockets of locally heavy rainfall
will be possible due to the intense rain rates. Right now, the
latest deterministic guidance and ensemble probabilities point
toward central to south TX with greater potential.

Along coastal Louisiana, a surface trough interacting with the
higher moisture in place will bring a higher coverage of
thunderstorms with the potential for intense rain rates and
localized heavy rainfall.

Taylor
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 040830
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
430 AM EDT Thu Jun 4 2026

Day 1
Valid 12Z Thu Jun 04 2026 - 12Z Fri Jun 05 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER A PORTION OF
THE UPPER MIDWEST...

Circulation around a broad area of high pressure over the
Northeast US and the Mid-Atlantic Region will keep an easterly flow
of deep moisture over Florida and and anticyclonic flow from the
Texas and Louisiana Gulf coast that becomes southwesterly from
parts of the Central Plains/Upper Midwest through much of the
period. An upper low over northern Mexico will help draw some of
that moisture westward to support the risk of locally heavy
rainfall there.

...Gulf Coast to Upper Midwest/Northern Plains...
With a persistent fetch of an airmass from the Gulf Coast region
into the Upper Midwest...precipitable water values increase
throughout the day...exceeding 2 inches along the Texas Gulf coast
to the ARKLATEX while increasing to 1.5 inches or more in a plume
extending into parts of Minnesota and Wisconsin. The highest
probability of heaviest rain was shown in both the operational
models and the ensembles across parts of Iowa into portions of
nearby Nebraska and Kansas as mid level height falls make their way
out of the High Plains and as surface pressures fall. Rainfall
rates of 1-2 inches per hour are possible. The 00Z runs of the HREF
and the RRFS show neighborhood probabilities of 10 to 20 percent
occurrence for 2 inch amounts in 3 hours for the 24 hour period
ending at 12Z Friday morning. Those rates could be enough to
overcome initially dry soils in parts of the area as well as be
problematic in urban areas.

Elsewhere along that corridor...there is sufficient CAPE to drive
locally intense downpours from any convection that forms. The big
problem is the relatively weak shortwave energy within the flow
will be difficult to time with much lead-time. As such...left the
Marginal Risk area pretty much in place with the expectation that
some area may well stay rain-free.

...West Texas to Eastern New Mexico...

An upper level system over Mexico will help draw some of the deeper
Gulf moisture westward...keeping a risk of locally heavy rainfall
and isolated instances of flash flooding. As previously
mentioned...the overall organization of the convection is expected
to be on the lower side, but the precipitable water anomalies and
the subtle increase in the upper level difluence near the
international border support potential for locally intense rain
rates and the Marginal Risk.

...South Florida...
Frontal boundary stalling in the vicinity of the area will remain
the focus for scattered to numerous showers and thunderstorms
capable of producing intense rain rates and locally heavy rainfall
over the highly urbanized corridor. The risk shifts a bit farther
south across South Florida compared with yesterday...mainly
centering across the Miami metro.

Bann


Day 2
Valid 12Z Fri Jun 05 2026 - 12Z Sat Jun 06 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE UPPER MIDWEST/NORTHERN PLAINS ON FRIDAY...

...21Z Outlook Update...
The ongoing forecast remainder largely on track. The main change
was the introduction of a Slight Risk across portions of Iowa to
parts of nearby Wisconsin and Illinois as areas of moderate to
heavy rainfall lingers in the area. Elsewhere...there were only
minimal changes needed to the Marginal Risk areas across the
central Gulf Coast to New Mexico...southern Louisiana and the
southern Florida peninsula.

Upper Midwest...
Additional scattered thunderstorm activity is expected once again
ahead of a front making its way from Iowa into Wisconsin and
vicinity, spreading 1-2 inches of rain with local amounts reaching
4 inches. Storms in that area should be progressive in nature due
to 20-30 knot mid/upper level flow, though localized backbuilding
and mergers may increase totals locally.

The Marginal Risk surrounding the Slight Risk was largely
unchanged...although some of the territory was removed from the
northern part of Michigan now that timing of the boundary and low
level moisture fields have become handled better by the
models/ensembles.

Texas into New Mexico...
Weak mid/upper troughing across the southern Rockies and Texas
will promote another round of thunderstorm activity across a large
part of Texas and southern New Mexico, with attendant flash
flooding expected due to slow storm motions and abundant moisture.

Coastal Louisiana...
A trough of low pressure interacting with the higher moisture in
place will bring a higher coverage of thunderstorms with the
potential for intense rain rates and localized heavy rainfall.
Spaghetti plots show more ARW core members than NMMB...suggesting
that there could still be shifts in placement or QPF amounts
between now and the time the outlook verifies.

South Florida...
A stalled frontal boundary over the southern Florida peninsula
will continue to focus scattered to numerous afternoon and evening
showers and thunderstorms. Given the instability...intense rain
rates and locally heavy rainfall over the highly urbanized
corridor.

Bann


Day 3
Valid 12Z Sat Jun 06 2026 - 12Z Sun Jun 07 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE GREAT LAKES/OHIO VALLEY AND ACROSS THE MIDDLE GULF COAST INTO
THE SOUTHERN PLAINS...

Great Lakes/Ohio Valley...
Maintained a Marginal Risk area over portions of Ohio Valley and
nearby southern Great Lakes as a front become oriented along an
east to west axis and flow aloft is weakly forced to lift
isentropically. Maximum areal average rainfall after the start of
the period at 12Z Saturday generally looks to be little more than
an inch. The cumulative effect of rainfall on Days 2 and 3
suggested it was too early to entirely remove the Marginal.

Texas northward into the Southern Plains...
Little change in the overall synoptic pattern is expected with
southerly flow of moisture continuing to be drawn into parts of the
Southern Plains. Some stronger/better defined shortwave energy
within the flow aloft will promote yet another round of
thunderstorm activity across a large part of Texas and southern New
Mexico and extending as far north as parts of Oklahoma/Arkansas and
Kansas by late Saturday night/early Sunday morning, with attendant
flash flooding expected due to slow storm motions and abundant
moisture.

Bann
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 050817
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
417 AM EDT Fri Jun 5 2026

Day 1
Valid 12Z Fri Jun 05 2026 - 12Z Sat Jun 06 2026

...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
EASTERN NEBRASKA/KANSAS INTO THE MID-MISSISSIPPI VALLEY AS WELL AS
MUCH OF TEXAS/SOUTHERN OKLAHOMA...

...Eastern Nebraska/Kansas to Mid-MS Valley...

A northern stream shortwave with multiple embedded vort maxes will
move through the Midwest Friday and provide lift for convection.
First, convection and potential for flash flooding looks to be
ongoing as the period begins 12Z Friday morning generally near the Iowa/Missouri and Iowa/Illinois border. This also sends
precipitation into Wisconsin and Lower Michigan in the morning to
early afternoon, but ahead of the influx of instability, so this is
a more Marginal flood threat. The next and likely stronger energy
in the shortwave, along with a cold front slowly shifting
southward, will help develop another round of storms beginning in
the afternoon and likely becoming enhanced in the evening and
overnight hours. The HREF and its members as well as the REFS show
this should be centered in southeastern Nebraska and northeastern
Kansas to southern Iowa, with periods of QPF exceeding FFG (HREF
and REFS probabilities 20-50% for FFG exceedance). A Slight Risk
remains reasonable for this activity, but upgrades are not out of
the question if training looks to overlap with the currently
ongoing (Thursday night) convection.

...Texas to Southern Oklahoma...

A compact southern stream upper low is forecast to drift from
northern Mexico across Texas during the Day 1 period. This lifting
mechanism will be paired with precipitable water anomalies in the
90-95th percentile in the southern Plains. There is some
uncertainty in magnitude of instability due to cloud cover, but
models show CAPE being sufficient at generally 1000-3000 J/kg, with
the low aloft helping steepen lapse rates. Scattered convection
that has the ingredients for flash flooding is likely to occur, so
went with an upgrade to a broad Slight Risk in this issuance. The
exact focus for the heaviest rain remains somewhat elusive, but
there is some signal in the CAMs for east-central Texas. Also
included areas to the west in the Slight, to include some of the
typically more sensitive/lower FFG areas in the Hill Country to
Concho Valley and Permian Basin. The Marginal Risk stretches back
into New Mexico where there are some sensitive areas like burn scars.

...Central Gulf Coast...

A disturbance likely in the form of a trough at low levels is
forecast to drift slowly toward the central Gulf Coast,
specifically southeastern Louisiana and southern Mississippi. With
moisture anomalies over the 90th if not the 95th percentile and
sufficient instability, intense rain rates could lead to a flooding
threat in the form of a Marginal Risk. Though typically not a very
sensitive area to flash flooding, antecedent wet conditions could
enhance the potential. The back end of the trough could also lead
to heavy rain in the Florida Keys, with the HREF and REFS
neighborhood probabilities of reaching over 5 inches of rain
greater than 60 percent, but considering the possibility the
heaviest rain could be offshore and how much rain the Keys can
handle with the sandy soils, held off on any risk area.

Tate


Day 2
Valid 12Z Sat Jun 06 2026 - 12Z Sun Jun 07 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE SOUTHERN PLAINS TO MISSISSIPPI VALLEY...

...Southern Plains/Mississippi Valley...

The meteorological setup on Saturday across the south-central U.S.
will be similar to Friday, through with the compact upper low
gradually tracking north across the southern half of the Plains.
The continued enhanced moisture and instability will yield an
environment favorable for convection with intense rain rates
causing flash flooding concerns. Areas farther north into Oklahoma
should see stronger forcing, while the low level jet could be
maximized farther south into Texas. Thus covered all this area with
a Slight Risk. REFS probabilities (which extend through the Day 2
period) show scattered instances of QPF potentially exceeding FFG.
Smaller scale boundaries leftover from thunderstorms on previous
days could provide areas of focus that would likely be unclear
before the near term.

...Central Gulf Coast...

By Saturday the surface/low level trough mentioned in the Day 1
discussion should reach the central Gulf Coast during the day, and
produce heavier QPF on land compared to Friday. Once again,
antecedent conditions in the region are not typically sensitive,
but are wetter than normal. REFS probabilities of exceeding FFG are
20-40% in southeast Louisiana, so will continue to monitor if slow storms/training are likely to cause more Slight Risk level impacts
and need an upgrade.

...Ohio Valley...

The northern stream shortwave is forecast to push through the Great
Lakes/Ohio Valley and Northeast on Saturday, with a frontal system
ahead of it. The front should lay west to east across the Ohio
Valley, so scattered storms could train and cause isolated flash
flooding. The Northeast can also expect some convection, but likely
progressive enough to limit flash flood potential to below a
Marginal. In this ERO issuance, connected the Plains and Ohio
Valley Marginal Risks together. There is some potential for storms
back into northern Missouri and vicinity, which could be very wet
after multiple rounds of convection, so wanted to cover that area.

Tate


Day 3
Valid 12Z Sun Jun 07 2026 - 12Z Mon Jun 08 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE SOUTHERN/CENTRAL PLAINS TO LOWER/MIDDLE MISSISSIPPI VALLEY...

Into Sunday, southern stream energy will continue to push north
through the central/northern Plains and Midwest while opening up
into a trough. This will once again provide forcing for
thunderstorms in the Plains and Mississippi Valley. A low level jet
of 30-40 kt should bring instability and moisture into the region.
The best overlap of ingredients for flash flooding, supported by
GEFS/ECens probabilities for over an inch of rain, will likely be
centered over Missouri south into Arkansas and west into eastern
parts of Kansas and Oklahoma, so this is where the Slight Risk is
drawn for Day 3. Some convection could linger farther south toward
the Gulf Coast, which the Marginal covers. By Sunday night, a
northern stream trough with a strong vort max is forecast to push
into the northern High Plains, bringing enhanced QPF ahead of it
for a Marginal Risk stretching through portions of the Dakotas and
western Minnesota.

Tate
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 060800
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Sat Jun 6 2026

Day 1
Valid 12Z Sat Jun 06 2026 - 12Z Sun Jun 07 2026

...THERE ARE SLIGHT RISKS OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
SOUTHERN PLAINS, OHIO VALLEY, UPPER TEXAS COAST, AND CENTRAL GULF COAST...

...Southern Plains...

A plume of deep tropical moisture will surge northward across the
Southern Plains on Saturday. The low level jet advecting this
moisture north will run into an area of enhanced lift due to a
nearby upper level shortwave, which will be lifting northeast to
rejoin the jet. The result will be a series of rounds of storms
moving north-northeast across portions of north Texas, eastern
Oklahoma and western Arkansas. Highly efficient warm rain processes
will dominate due to the present of such abundant amounts of
moisture, with PWATs close to 2 inches. For eastern
Oklahoma/western Arkansas, the rain will persist for much of the
day in the form of training lines of storms. Back into Texas, the
threat will be mostly overnight tonight due to persistent storms
associated with an MCS that will drift east across far north Texas
and southern Oklahoma. An internal higher-end Slight was introduced
from southwest of the Metroplex through it, and continuing into
much of eastern Oklahoma and western Arkansas for the combination
of two areas of persistent heavy rain. Overall changes from
inherited were minimal.

...Ohio Valley...

A very-slow moving cold front drifting south across the
Midwest/Ohio Valley on Saturday will be the animus for multiple
rounds of storms which will track east-southeast from Indiana east
to the central Appalachians. A new Slight Risk area was introduced
with this update. In the upper levels, a shortwave may help the
storms become stronger for the first part of the period before
shifting off to the east. The front will form the leading nose of a
plume of deep Gulf moisture tracking northward up the Mississippi
Valley. The front will "shear" the moisture eastward in a narrow
corridor, along which the storms will form and move. Stronger and
more persistent storms from Indiana to western Ohio will become
somewhat less strong and less organized into the Mountains of
western Pennsylvania and West Virginia, but those areas will have
lower FFG thresholds, allowing the two areas to combine into one
Slight Risk area for somewhat different reasons. Uplift along the
western face of the Appalachians may also locally enhance rainfall rates.

...Upper Texas Coast...

In coordination with HGX/Houston, TX forecast office, a Slight Risk
upgrade was introduced with this update. Extreme amounts of
moisture will be in place throughout the atmosphere of southeast
Texas Saturday afternoon. PWATs between 2 and 2.25 inches are 3
sigma above normal for this time of year, an impressive threshold
to meet for June. With peak heating this afternoon, scattered
showers and thunderstorms are expected to form, likely 20-50 miles
inland from the coast. Cold pools from Friday's storms and new ones
from the storms that form Saturday afternoon will likely drive new
storm development along the I-10 corridor from southwest of Houston
to the TX/LA border near Beaumont. With plenty of new moisture
streaming north off the Gulf, the storms will have no trouble
reforming and training over the same areas for the duration of the
long afternoon. Nightfall should end the storms in the area due to
lack of other forcing and the loss of instability. Friday's storms
have knocked down FFGs in this region significantly, and with good
capability of efficient warm rain processes, urban concerns in
Houston, and slow storm movement were all reasons contributing to
the Slight Risk upgrade.

...Central Gulf Coast...

Few changes were needed to the Slight Risk area from New Orleans
east to Pensacola. A strong front is in place across the eastern
Gulf, characterized by very dry air to its east, rather than any
significant temperature gradient. The dry air is 2 sigma below
normal over portions of central Florida...under 1 inch PWATs.
Meanwhile to the west from Louisiana through Texas, an abnormally
moist air mass will be streaming north to the west of the high
pressure area characterized by the dry air. Over much of Louisiana,
PWATs will be over 2.25 inches or 3 sigma above normal. The front
makes up the gradient between these extremely contrasting air
masses. Through the day, the front will push east as the moist air
mass gradually gains ground. However, the front will be the forcing
along which numerous showers and thunderstorms pushing north out of
the Gulf will form along. The front will be slow to move, allowing
repeating rounds of storms to impact the central Gulf Coast. FFGs
are high, about 4 inches/hour, but the repeating rounds of storms
should rather quickly bring those numbers down, allowing for widely
scattered instances of flash flooding to develop where the rains
are most persistent by late afternoon. Nightfall should see a
decrease in shower and storm activity, ending the flooding threat.

Wegman


Day 2
Valid 12Z Sun Jun 07 2026 - 12Z Mon Jun 08 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR MUCH OF THE
MID-MISSISSIPPI VALLEY, OZARKS, AND THE WESTERN TENNESSEE VALLEY...

A pair of forcings will work cause renewed rounds of showers and
storms across much of the Mississippi Valley on Sunday into Sunday
night. A slow moving but still potent upper level low will track
northeastward up the Plains and into the Midwest by late Sunday
night. Meanwhile a strong front oriented north-south will allow for
shower and thunderstorm development further east across portions of
the South. For the Mid-Mississippi Valley and Ozarks, the shortwave
will be the primary forcing. Deep tropical moisture characterized
by PWATs on either side of 2 inches will advect northward up the
Mississippi Valley. The shortwave will provide the forcing for
storms to form, along with the topography of the Ozarks. Many of
these areas, especially from far eastern Oklahoma, northwestern
Arkansas, and southwest Missouri have seen repeated rounds of heavy
rain in recent days, so FFGs are lower in this area. Thus, a
higher-end Slight was introduced for this area depicting an even
greater threat for flash flooding, as the topography of the Ozarks
works to increase the severity of any flooding. FFGs are also lower
from northern Missouri into Iowa. Storms forming in these areas
will be closer to the nose of the low level jet, though the upper
level shortwave should still be the primary forcing.

The Slight Risk area was expanded north up the Mississippi Valley
into southern and eastern Iowa and western Illinois with this update.

For portions of the western Tennessee Valley, including western
Tennessee far northeastern Mississippi, and especially northern
Alabama, the aforementioned north-south oriented front will be the
primary forcing for the first half of the day. The front will more
rapidly retreat east across Georgia by Sunday night, leaving any
forcing to weak upper level shortwaves. Thus, most of the storms
will be during the afternoon and evening during peak heating and
when the front is closer. FFGs are lower across northern Alabama
from recent heavy rainfall, around 2.5 in/hour, which due to PWATs
occasionally over 2 inches, should be easily attainable by the
strongest storms expected Sunday afternoon. Thus, the Slight Risk
was expanded southeast for these reasons.

Wegman


Day 3
Valid 12Z Mon Jun 08 2026 - 12Z Tue Jun 09 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE MID-MISSISSIPPI, LOWER OHIO, AND WESTERN TENNESSEE VALLEYS...

On Monday, the excessive rainfall risk translates a bit further
north and east into the Mid-Mississippi, lower Ohio, and western
Tennessee Valleys. A strong front over the Great Lakes will retreat northeastward as the plume of anomalously deep moisture from the
Gulf surges northeastward to replace the drier air mass in place
over the Northeast. A slow-moving negatively tilted trough will
also promote upper divergence and lift throughout the atmosphere
over the Slight Risk area throughout the period. PWATs around 2
inches will be 3 sigma above normal for this time of year across
the region, so many of the storms that form will consist of highly
efficient warm rain processes, which will promote heavy rainfall.
FFGs across the region will average around 2-2.5 inches, which will
be easily overcome by many of the strongest cells, so long as their
forward speed is kept in check. The Slight Risk area was nudged
west over more of southeastern Missouri with this update, adjusted
for expected heavy rainfall and likely lower FFGs in this region
from the Day 2/Sunday period.

Wegman
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 070816
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
416 AM EDT Sun Jun 7 2026

Day 1
Valid 12Z Sun Jun 07 2026 - 12Z Mon Jun 08 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR MUCH OF THE
MID-MISSISSIPPI VALLEY, OZARKS, AND WESTERN TENNESSEE VALLEY...

Numerous thunderstorms are expected to form this afternoon into
tonight over a broad area spanning across the Great Plains and
Mississippi, Ohio, and Tennessee Valleys. Three primary forcings
will trigger storms: an upper level shortwave moving north across
the central Plains, Mid-Mississippi Valley, and Upper Midwest, a
strengthening cyclone emerging in the northern/central Plains, and
a quasi-stationary frontal boundary draped across the Mid-
Mississippi and Ohio Valleys. These features will interact with a
moist, unstable air mass that will support efficient rainfall
processes that could lead to heavy rainfall. Deep, moist southerly
flow has primed the atmosphere across the Plains and Mississippi
Valley, increasing PWAT values to around 2 inches (2-2.5 standard
deviations above normal for this time of year). Hi-res CAM guidance
suggests rainfall rates of 2-4 inches per hour will be possible in
thunderstorm cells across the Mid-Mississippi Valley and portions
of the Ozarks and western Tennessee Valley, which would exceed
current flash flood guidance and result in scattered instances of
flash flooding within the Slight Risk area. Areas from eastern
Oklahoma into western Arkansas and east-central Illinois into west-
central Indiana may be more susceptible to flash flooding after
rainfall yesterday left soils thoroughly saturated. Heavy rain will
likely result in locally high rainfall totals, potentially
reaching 5-7 inches for some locations within the Slight Risk area.

Locally heavy rainfall will also extend along the quasi-stationary
frontal boundary into Ohio Valley. Storms forming along the
boundary will have the potential to produce rainfall rates over 2
inches per hour, and storm motion will be fairly slow. However,
convection should be more isolated over the Ohio Valley portion of
the front, resulting in only a Marginal Risk. Stronger convection
will also be possible in the vicinity of the low pressure system
over the northern Plains, but storms will be much more progressive
in this region, which will limit heavy rainfall potential and the
risk of flash flooding. The Marginal Risk area extends across the
northern Plains to account for isolated flash flood potential with
stronger thunderstorms that may form.

Dolan


Day 2
Valid 12Z Mon Jun 08 2026 - 12Z Tue Jun 09 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE MID-MISSISSIPPI, LOWER OHIO, AND TENNESSEE VALLEYS...

On Monday, the northern stream cyclone will move north into
Canada, which will lift the previously stationary frontal boundary
north across the Upper Midwest and Great Lakes as a warm front and
push the tail end of the front south into the Carolinas. Heavy
rainfall potential will be focused in the warm sector of the system
over the Mid-Mississippi, lower Ohio, and Tennessee Valleys where
a very moist and unstable air mass will still be in place. A
splitting upper level shortwave will push some energy across these
regions, which will support a broad area of widespread/numerous
thunderstorms. With weakening steering flow, storm motions are
expected to become very slow, which will heighten the threat of
flash flooding. The RRFS shows modest probabilities (20-40%) of
hourly rainfall rates exceeding 2 inches per hour for several hours
across the Slight Risk area. Some of these areas will also receive
heavy rainfall during the day 1 period, which may increase the
risk of flash flooding if areas are impacted by additional storms
with heavy rainfall on Monday.

Outside of the Slight Risk area, a broad Marginal Risk area extends
into the Upper Midwest and central Plains. Anomalous moisture will
surge north behind the lifting warm front, which will support
locally heavy rainfall that may lead to isolated instances of flash
flooding for the western Great Lakes states. Models have also
started consistently showing a potential MCS forming underneath a
potent upper level shortwave moving quickly east across the central
Plains on Monday evening. Though this feature would likely be
progressive, it could have the potential to produce heavy rainfall
and isolated flash flooding. There is still some uncertainty
regarding the location of this feature, resulting in a broad
Marginal Risk area that will likely be narrowed down over the next
few forecast cycles.

Dolan


Day 3
Valid 12Z Tue Jun 09 2026 - 12Z Wed Jun 10 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE UPPER MIDWEST AND OHIO AND TENNESSEE VALLEYS...

On Tuesday, an upper level trough will move across the
northwestern U.S. and support cyclogenesis over the northern
Plains. A wave of convection is expected to form ahead of the
developing cyclone, bringing thunderstorms to much of the Upper
Midwest. A moist and unstable air mass will be in place across the
Upper Midwest after a warm front lifts north on Monday, which will
support heavy rainfall in thunderstorms. Flash flood potential
should be limited by the progressive nature of this system, but
locally heavy rainfall could still lead to isolated instances of
flash flooding, especially where soils will be moistened from
rainfall expected on Sunday and Monday. A Marginal Risk area seems
sufficient to cover the flash flood threat at this time.

Another Marginal Risk area is in place for much of the Ohio and
Tennessee Valleys and portions of Michigan where a slow moving
frontal boundary will linger through Tuesday. This frontal boundary
will provide modest lift/support for scattered convection across
these regions. An anomalously moist air mass will still be in
place, which should be enough to support locally heavy rain in some
stronger storms and may lead to isolated instances of flash
flooding. The flash flood threat will be significantly lower for
these regions than on Monday with much weaker synoptic support.

Dolan
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 080819
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
419 AM EDT Mon Jun 8 2026

Day 1
Valid 12Z Mon Jun 08 2026 - 12Z Tue Jun 09 2026

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE OZARKS...

Convection will be ongoing at the start of the period across the
Ozarks where a low level jet ahead of a mid-level vortex/wave will
create favorable convective conditions that will likely lead to
impactful flash flooding, especially near steep terrain. During the
early morning hours, hi-res CAMs are showing rainfall totals as
high as 5-8 inches for portions of southeastern Kansas,
northeastern Oklahoma, southwestern Missouri, and northwestern
Arkansas where slow, back-building thunderstorms are expected. An
anomalously moist and unstable air mass is already in place across
the central U.S., which will support deep convection with highly
efficient rainfall rates (rates of 2-3 inches per hour are already
being observed). This region was incorporated in a special update
Moderate Risk area overnight, and the Moderate Risk will continue
into the beginning of the Day 1 period this morning. Convection
should wane and shift southeast later this morning into this
afternoon as the system becomes dominated by the outflow.

The broader Slight Risk area includes much of the Middle
Mississippi and Tennessee Valleys where widespread showers and
thunderstorms are expected in the warm sector of a northern stream
cyclone today. Much of the convective activity will be driven by
mesoscale boundaries and remnant MCV activity continuing from the
overnight period, which will result in variability of the QPE
across the warm sector. Some convection may be more focused along a quasi-stationary frontal boundary draped over the Tennessee Valley
and southern Appalachians. Convection will be enhanced by a
leading upper level shortwave with embedded MCV activity that will
push east across these regions, and the environment will be
extremely supportive of heavy rainfall with high moisture (PWAT
values around 2 inches) and high instability (MUCAPE greater than
3000 J/kg). Storms are expected to be slow moving due to a lack of
steering flow, which will allow for locally high rainfall totals.
Latest CAM guidance suggests rainfall rates up to 2-3 inches per
hour and totals up to 5-8 inches will be possible over portions of
the Middle Mississippi and Tennessee Valleys. HREF neighborhood
probabilities show the highest chances of exceeding 5 inches of
rainfall in 24 hours (25-45%) will be over an area from southern
Illinois and Indiana through western Kentucky and Tennessee. These
areas can expect impacts on the higher end of the Slight Risk
category. Some of the areas within the Slight Risk received heavy
rainfall on Sunday, which may increase the risk of flash flooding
if areas are impacted by additional storms with heavy rainfall
today. The Slight Risk areas has also been extended north into
central Wisconsin and eastern Iowa where slow-moving storms are
expected to be enhanced by a mid-level low this afternoon.

Outside of the Slight Risk area, a broad Marginal Risk area extends
into the Upper Midwest and central Plains where locally heavy
rainfall may lead to isolated instances of flash flooding. Storms
across much of the Upper Midwest should be fairly progressive,
which will limit flash flood potential, but isolated flooding
concerns will be possible if heavy rainfall impacts any urban
areas. Models continue to also show a potential MCS forming
underneath a potent upper level shortwave moving quickly east
across the central Plains this evening. Though this feature would
be very progressive, deep convection will have the potential to
produce heavy rainfall and isolated flash flooding. This shortwave
may also enhance convection again over the Middle Mississippi
Valley tonight, and there could be a scenario where a targeted
Moderate Risk area is needed.

Dolan


Day 2
Valid 12Z Tue Jun 09 2026 - 12Z Wed Jun 10 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
NORTHERN PLAINS AND WESTERN KENTUCKY AND TENNESSEE...

On Tuesday, a potent upper level trough will move across the
northern Rockies and emerge into the northern Plains. This trough
will spur cyclogenesis over the northern Plains while a low level
jet increases moisture and instability ahead of the system. The
environment will be ideal for supercell development Tuesday
afternoon, and increasing shear over the region will allow storms
to evolve into an MCS Tuesday evening into Tuesday night. Deep
convection within these severe storms will be able to tap into
moisture in the atmosphere (PWAT values 1.5-2 inches) and create
very heavy rainfall. The quick nature of the MCS should somewhat
limit the risk of flash flooding, but intense rainfall rates in
excess of 2 inches per hour will exceed FFGs and could lead to
impactful flash flooding, especially in urban areas. A Slight Risk
area has been introduced for much of central and eastern North
Dakota and northwestern Minnesota.

Scattered showers and storms are forecast from the southern
Appalachians and Tennessee Valley through the Ohio Valley and Great
Lakes region, which will be supported by an upper level shortwave
lifting northeast across the Ohio Valley and Great Lakes and a slow
moving warm front extending south into the Tennessee Valley and
southern Appalachians. The air mass in place will be anomalously
moist (PWATs around 2 inches) and sufficiently unstable to support
locally heavy rainfall. Available hi-res guidance suggests higher
rainfall totals will be possible across western Kentucky and
Tennessee where convection will continue from the Day 1 period into
Tuesday morning. A mid-level shortwave will be enhancing this
convection and should allow for efficient rainfall rates over 2
inches per hour. A Slight Risk area has been introduced to cover
the elevated flash flood threat over western Kentucky and
Tennessee. Global models have also been showing locally enhanced
rainfall totals over portions of the Ohio Valley, but there is
still a significant amount of uncertainty in the location of these
higher totals. It is possible the Slight Risk area may need to be
expanded to the northeast as convective details become more clear
with additional hi-res guidance available later today.

Dolan


Day 3
Valid 12Z Wed Jun 10 2026 - 12Z Thu Jun 11 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM EASTERN KANSAS
INTO NORTHERN MISSOURI AND SOUTHERN IOWA...

On Wednesday, the northern Plains cyclone will be moving swiftly
east and pushing a cold front across the Midwest. Showers and
thunderstorms are expected ahead of and along the frontal boundary
from the Midwest to the central Plains, which are encompassed by a
Marginal Risk of excessive rainfall. The tail end of the front will
likely hang up on the Rockies and flatten out over the central
Plains, and low pressure is expected to develop over Kansas where a
dryline will intersect the boundary. Models are showing impressive
moisture transport ahead of the frontal boundary Wednesday morning
and a secondary surge Wednesday night as a strong low level jet
brings increasing moisture and instability into the central Plains.
This set up will be conducive for heavy rainfall, and global models
are showing potential for heightened rainfall totals of 2-4 inches
within the Slight Risk area, which may be underdone given the
convective limitations of the models. Locally heavy rainfall may
also be possible over central Wisconsin and could impact areas
highlighted with a Slight Risk on Day 2, which could warrant an
additional Slight Risk upgrade. However, there is much more
uncertainty regarding rainfall totals in Wisconsin, which may be
limited by the progressive nature of the cold front.

Dolan
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 090818
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
418 AM EDT Tue Jun 9 2026

Day 1
Valid 12Z Tue Jun 09 2026 - 12Z Wed Jun 10 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
NORTHERN PLAINS, OHIO AND TENNESSEE VALLEYS, AND SOUTHERN APPALACHIANS...

.Northern Plains...
A potent upper level trough will push across the northern Rockies
into the Plains today and spur cyclogenesis over the northern
Plains. Low pressure will strengthen over the region with a cold
front extending to the southwest and a warm front extending to the
east. Southerly winds ahead of the trough will direct warm, moist,
unstable air into the northern Plains, with PWAT values expected to
exceed 1.5 inches and MUCAPE expected to rise above 3000 J/kg.
Increasing mid/low level winds on the leading edge of the trough
will create a highly sheared environment that is conducive for
supercell development this afternoon. By this evening, an
intensifying low level jet oriented parallel to the surface cold
front will support upscale convective growth into a linear MCS.
Deep convection within supercells and eventually the more organized
MCS will be able to tap into the atmospheric moisture to produce
very intense rainfall rates in excess of 2 inches per hour.
Relatively fast storm motion will be a limiting factor to the flash
flood risk, but rainfall rates will be enough to overwhelm FFGs
and cause flash flooding, especially if heavy rain occurs in urban environments. A Slight Risk of excessive rainfall remains in effect
for the heaviest convective activity expected over central and
eastern North Dakota and northwestern Minnesota. A broader Marginal
Risk area extends into the Midwest where convection may focus
along a surface boundary extending from the northern Plains cyclone tonight.

.Ohio and Tennessee Valleys and southern Appalachians...
An upper level trough will lift northeast across the Midwest and
Great Lakes region today accompanied by a surface low over the
Great Lakes and a slow-moving warm front extending south into the
Ohio and Tennessee Valleys. The air mass in place across these
regions will be anomalously moist with PWAT values around 2 inches,
2-2.5 standard deviations above normal for this time of year.
There will also be sufficient synoptic forcing and instability to
support scattered to potentially widespread convection from the
Great Lakes to the Interior Southeast. Convection will be ongoing
at the start of the period and should translate east throughout the
day as the system progresses. High moisture content in the
atmosphere will support chances for locally heavy rainfall, and
more intense rainfall may be possible over the Ohio and Tennessee
Valleys where convection will be enhanced by a couple quick-moving
mid-level waves rounding the top of the ridge positioned over the
Gulf. The first wave will pass over the region early in the period,
resulting in a burst of more intense convection this morning. The
second wave will pass over this area tonight into early Wednesday
morning and will have the potential for back-building storms along
a surface boundary extending into the lower Ohio Valley from the
northern Plains cyclone. Hi-res guidance suggests rainfall rates of
2-3 inches will be possible in stronger cells, and most hi-res
CAMs are showing a swath of rainfall totals of 3-5 inches, with
locally higher amounts, across portions of Kentucky and maybe
southern Indiana as well. The HREF and RRFS are both showing
relatively high probabilities (50-70% and 40-50% respectively) of
24 hr totals exceeding 5 inches in this area. Enhanced convection
will also be possible, but to a lesser extent, under the upper
waves over Tennessee and in upslope areas of the southern
Appalachians. Some areas may be more susceptible to heavy rain
today after recent heavy rains over the past few days. A Slight
Risk of excessive rainfall covers the area of enhanced convection
over the Ohio and Tennessee Valleys and southern Appalachians and
a Marginal Risk area extends north through the Great Lakes.

Dolan


Day 2
Valid 12Z Wed Jun 10 2026 - 12Z Thu Jun 11 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR NORTHEASTERN
KANSAS, SOUTHEASTERN NEBRASKA, NORTHERN MISSOURI, AND SOUTHERN IOWA...

.Midwest and central Plains...
On Wednesday, the northern Plains cyclone will move into south-
central Canada and push a trailing cold front across the Midwest.
Showers and storms will be ongoing Wednesday morning ahead of the
system over northern Minnesota, then another round of convection is
expected across the Midwest and central Plains Wednesday afternoon
and evening ahead of and along the cold front. Deep southerly flow
ahead of the system will increase PWAT values to 1.5-2 inches,
with the higher values focused between northern Missouri and
southern Wisconsin. Instability should increase through the
afternoon as daytime heating kicks in, but the best instability
(3000-4000 J/kg) looks like it will focus from eastern Kansas and
southeastern Nebraska into northern Missouri and southern Iowa,
where there is a Slight Risk of excessive rainfall. This area will
likely experience a period of enhanced convection Wednesday night
as a frontal wave develops at the intersection of the cold front
and a dryline. A secondary wave of moisture and instability will
surge into the central Plains as a low level jet strengthens
Wednesday night, which should support efficient rainfall rates,
potentially exceeding 2 inches per hour, that could lead to
scattered instances of flash flooding. There is still some
uncertainty regarding rainfall totals within the Slight Risk area.
If the frontal wave is more progressive, the risk of flash
flooding may be limited. A broader Marginal Risk area surrounds the
Slight Risk and extends up through the Midwest where strong
convection could result in at least isolated instances of flash flooding.

.Tennessee Valley and southern Appalachians...
Convection should be ongoing across portions of the Tennessee
Valley and southern Appalachians at the start of the period. A
quick-moving upper level wave will round the top of the ridge
positioned over the Gulf and support a period of enhanced
convection late Tuesday night into Wednesday morning. Anomalous
moisture and sufficient instability will be in place to support
efficient rainfall rates, and slow storm motions will contribute to
high rainfall totals. There will also be some potential for back-
building storms along a surface boundary extending from the
northern Plains/southern Canada cyclone into the Tennessee Valley,
mainly focusing over Kentucky. Showers and storms will also be
enhanced by upslope flow along the southern Appalachians.
Convection should start to weaken Wednesday morning and wane by
Wednesday afternoon, but there will at least be enough rainfall
over saturated soils to continue a Marginal Risk of excessive
rainfall into Wednesday morning.

.Interior Northeast...
A Marginal Risk of excessive rainfall was introduced for portions
of the Interior Northeast. An upper level trough will cross over
the Great Lakes into southeastern Canada accompanied by a surface
low pressure system that will bring precipitation chances to much
of the Northeast. The warm sector of this system will be
characterized by an anomalously moist air mass with PWAT values up
to 2 inches. There should be enough moisture and synoptic forcing
to support locally heavy rainfall in stronger convection near the
low pressure center over southeastern Canada and the Interior
Northeast. Rainfall totals and flash flood potential may also be
increased by terrain and upslope flow Wednesday afternoon.

Dolan


Day 3
Valid 12Z Thu Jun 11 2026 - 12Z Fri Jun 12 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM NORTHEASTERN
MISSOURI THROUGH EASTERN IOWA AND NORTHERN ILLINOIS TO SOUTHERN WISCONSIN...

The frontal wave that developed over the central Plains Wednesday
night will progress northeast and intensify as a strong upper
trough swings into the northern and central Plains Thursday
morning. A strong low level jet will increase moisture and
instability across the central Plains Wednesday night, and this air
mass will expand towards the Upper Midwest as southerly winds surge
ahead of the surface frontal boundary. A large swath of high PWAT
values above 2 inches will stretch from the southern Plains to the
Midwest, which will support a broad area of convection capable of
producing locally heavy rainfall. A wave of deeper convection will
accompany the strong frontal wave as it progresses, resulting in
high rainfall totals over an area from northeastern Missouri
through eastern Iowa, northern Illinois, and southern Wisconsin.
These areas are highlighted by a Slight Risk of excessive rainfall
to account for enhanced convection capable of producing scattered
instances of flash flooding. A broader Marginal Risk of excessive
rainfall surrounds the Slight and includes much of the Midwest and
portions of the central and southern Plains.

Dolan
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 100813
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
413 AM EDT Wed Jun 10 2026

Day 1
Valid 12Z Wed Jun 10 2026 - 12Z Thu Jun 11 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
CENTRAL PLAINS AND MIDWEST...

.Midwest and Central Plains...
A strengthening cyclone will be moving northeast into south-
central Canada and push a cold front across the north-central
United States, which will trigger scattered showers and
thunderstorms ahead of and along the front. A warm front will lift
north ahead of the system, establishing a broad warm sector from
the central Plains to the Upper Midwest. The warm sector air mass
will be characterized by anomalously high moisture content, with
PWAT values rising to 1.75-2.25 inches. Increasing temperatures
and moisture will also result in increasing instability, with the
highest MUCAPE (> 3000 J/kg) expected to concentrate over eastern
Kansas, northern Missouri and eastern Iowa. Storms forming in this
area will have the potential to produce heavy downpours with
rainfall rates of 2-3 inches per hour, which would exceed FFG in
much of this region. Storms forming further north along the front
will also have the potential to produce locally heavy rainfall as
well. Instability should be sufficient for deep convection across
portions of Minnesota, Wisconsin, and Illinois, and convection may
become more organized this afternoon with increasing shear along
the frontal boundary.

There remains some uncertainty regarding where the heaviest
rainfall totals will be, but the HREF and RRFS generally agree on
an area of elevated totals from northern Illinois through
Wisconsin. This area will likely receive some locally heavy
rainfall this morning from an eastward propagating MCS out ahead of
the surface frontal boundary, then another wave of convection
should ignite across the region this afternoon as the front
approaches. For the central Plains, rainfall totals have generally
trended downwards over the past 48 hours, most likely due to a more
progressive frontal boundary that is oriented SW-NE instead of
W-E, reducing convergence across the region. The synoptic setup
should become more conducive for heavy rainfall over the central
Plains late tonight into early Thursday as a frontal wave develops
along the boundary and triggers an area of enhanced convection.
Moisture and instability will surge into the central Plains ahead
of this feature as a low level jet strengthens, which should
support efficient rainfall rates in excess of 2 inches per hour.
For these reasons, a Slight Risk of excessive rainfall extends from northeastern Kansas and southeastern Nebraska to Wisconsin and
northern Illinois with a broader Marginal Risk area across much of
the east-central Plains and Midwest.

.Tennessee Valley and southern Appalachians...
An MCS is currently moving southeast across the Ohio Valley and
should move across the eastern Tennessee Valley and southern
Appalachians this morning. Rainfall rates up to 2-3 inches per hour
have been observed with this system overnight and will remain
possible as the system moves across eastern Kentucky. Convection
should weaken as the system is disrupted by the southern
Appalachians, but upslope flow may enhance rainfall totals over the
western Carolinas and western Virginia. Models have trended more
to the northeast with this MCS, resulting in a shift in the
Marginal Risk area, trimming out central Kentucky and most of
western Tennessee and expanding into western Virginia. Luckily,
rainfall from this system should be displaced from where heavy
rainfall was observed yesterday over central and western Kentucky,
but locally heavy rainfall may still lead to isolated instances of
flash flooding.

.Interior Northeast and Mid-Atlantic...
A surface low pressure system will track across southeastern
Canada today and lift a warm front across the Northeast. Upper
level troughing extending across the Northeast and Mid-Atlantic
will allow for a region of broad ascent that will support scattered
showers and thunderstorms. An anomalously moist air mass will push
into these regions behind the front, increasing PWAT values up to
around 2 inches (above the climatological 90th percentile), which
will allow for locally heavy rainfall with rates of 1-2 inches per
hour. Rainfall may also be enhanced by upslope flow over the
terrain in the Interior Northeast and central Appalachians. A
Marginal Risk of excessive rainfall covers portions of the Interior
Northeast, central Appalachians, Mid-Atlantic where isolated
instances of flash flooding will be possible.

.Southwest Florida...
Convection will ignite as the Atlantic and Gulf sea breezes
collide this afternoon over Southwest Florida. Southeasterly flow
will increase PWAT values across the Florida peninsula throughout
the day today, with the highest values (2.2-2.5 inches) focused
over South Florida. Given a very moist atmosphere with strong
convective forcing at the surface, thunderstorms will be able to
produce heavy rainfall rates. The latest HREF is showing high
probabilities (50-70%) of rainfall rates exceeding 2 inches per
hour, and hi-res CAMs suggest rainfall rates of 3-4 inches will be
possible in deeper convective cells. Rainfall rates this high will
likely create localized flooding concerns for urban areas in
Southwest Florida where there is a Marginal Risk of excessive rainfall.

Dolan


Day 2
Valid 12Z Thu Jun 11 2026 - 12Z Fri Jun 12 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE MIDWEST...

.Southern Plains to Midwest...
The frontal wave that developed over the central Plains Wednesday
night will surge northeast and intensify as a strong trough swings
across the north-central United States. Strong southerly flow ahead
of this wave will drive an anomalously moist and highly unstable
air mass into the Midwest that will support enhanced convection
in the vicinity of the frontal wave. Showers and storms will also
form along the frontal boundary as it progresses, extending back
into the southern Plains, but the progressive nature of the front
should somewhat limit the flash flood potential over the Plains.
Moisture will pool ahead of the cold front as it surges
southeastward, creating a swath of high PWAT values of 2-2.5 inches
from the southern Plains to the Great Lakes that will support high
rainfall rates in excess of 2 inches per hour. Available CAMs and
global models show a broad area of heavy rainfall across the
Midwest, which is encompassed by a Slight Risk of excessive
rainfall, and the highest rainfall totals are expected to focus
over eastern Iowa, northern Illinois, and southern Wisconsin. These
areas will have the highest risk of flash flooding on Thursday,
especially after heavy rainfall in the Day 1 period. Additional
heavy rain falling on top of saturated soils will make these areas
more susceptible to flash flooding, and there could be a scenario
where a targeted upgrade to a Moderate Risk may be needed. A larger
Marginal Risk area stretches from the Midwest to the southern
Plains where heavy rain may lead to isolated instances of flash flooding.

.Central Appalachians and Northeast...
An upper level shortwave trough is forecast to move southeast
over the Ohio Valley, Northeast, central Appalachians, and Mid-
Atlantic, which will trigger another round of scattered showers and thunderstorms on Thursday. An anomalously warm and moist air mass
will be in place across these regions, with PWAT values of 1.75-2
inches, which will support rainfall rates of 1-2 inches per hour.
The upper level shortwave will result in an increasingly sheared
environment over the Northeast Thursday afternoon, which will allow
for some organized convection with higher rainfall rates in excess
of 2 inches per hour. These storms should move quickly, but
intense rainfall rates will support a risk of at least isolated
instances of flash flooding for portions of eastern Pennsylvania,
northern New Jersey, southern/central New York, and Connecticut
where a Marginal Risk of excessive rainfall has been introduced.
Another Marginal Risk area has been introduced over the central
Appalachians from West Virginia into southwestern Pennsylvania
where persistent northwesterly upslope flow will support enhanced
precipitation chances in this area. Soils will be somewhat
saturated from rainfall expected in the Day 1 period, and isolated
flooding concerns may continue into Thursday with showers and
storms capable of producing rainfall rates of 1-2 inches per hour.

Dolan


Day 3
Valid 12Z Fri Jun 12 2026 - 12Z Sat Jun 13 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE SOUTHERN
PLAINS TO THE NORTHERN MID-ATLANTIC...

A low pressure system tracking across Canada will push a cold front
across the eastern and south-central United States on Friday. As
the frontal boundary interacts with the anomalously warm and moist
air mass in place across the South and East, scattered to numerous
showers and storms are expected to develop. PWAT values around 2
inches will stretch from the southern Plains to the northern Mid-
Atlantic, which should support efficient rainfall rates. High shear
in the vicinity of the upper level trough over the Northeast and
northern Mid-Atlantic will likely allow for some strong, organized
convection with the potential to produce heavy downpours. Storm
motion across the East should be relatively quick given the
progressive nature of the front, but this will be the third
consecutive day of active convection for this region, which will
support a risk of at least isolated flash flooding. The tail end of
the front will become quasi-stationary over the southern Plains
with broad southeasterly flow on the southern side of the
boundary. Warm, moist air will support convection with locally
heavy rainfall along the front, and convection may be enhanced
Friday evening as an upper level shortwave moves east across the
southern Plains. Showers and storms will likely extend west into
New Mexico where precipitation chances may be enhanced near the
Guadalupe and Sacramento Mountains. Locally heavy rainfall could
also pose a flood risk for burn scars in eastern New Mexico. A
Marginal Risk of excessive rainfall stretches from the southern
Plains to the northern Mid-Atlantic to cover these threats.

Dolan


Day 4 and Day 5
Valid 12Z Sat Jun 13 2026 - 12Z Mon Jun 15 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
THE CENTRAL AND SOUTHERN PLAINS AND MISSISSIPPI VALLEY THIS WEEKEND...

Active weather is anticipated across the Central/Southern Plains
and MS valley this weekend as a favorable environment for heavy
rainfall rates and training convection evolves southward. On
Saturday, a Slight risk of excessive rainfall continues for
portions of eastern KS, northeast OK, northwest AR and much of MO.
A strongly unstable airmass with CAPE locally over 3000 J/kg is
forecast to overlap with an increasing plume of above average
moisture. Large scale ascent focused within the right entrance
region of an upper level jet and amplified by subtle shortwave
features will interact with a corridor of strong 850mb moisture
transport. Given the resulting wind profiles, weak Corfidi vectors
are probable, favoring backbuilding and cell training. This results
in rather high confidence in some flash flood impacts, although
some spatial uncertainty persists. For the moment the Slight risk
area encompasses the region of best clustering in the multi model
ensemble (GEFS/ECENS/CMCE/AIFS ensemble).

On Sunday the threat of excessive rainfall shifts southward into
the Southern Plains and Lower MS Valley, targeting northeast TX,
central and eastern OK, northern LA, and much of AR. While the
overall environment remains similar to the previous day, deep
layer moisture is forecast to increase further, with PW values well
over the climatological 90th percentile expected. This environment
will remain supportive of high rainfall rate flash flood impacts,
although confidence in placement is lower due to some notable model
spread. The deterministic AIFS and AIGFS represent the farthest
south solutions, bringing the heaviest rainfall all the way towards
the TX Gulf Coast. However, traditional global ensemble clustering
remains further north, and even the AIFS ensemble mean is a bit
north of its deterministic run. The current Slight risk area
focused across the ArkLaTex region is where the full ensemble suite
(AI and physics based) shows the most overlap at this time.

Chenard
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 110808
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
408 AM EDT Thu Jun 11 2026

Day 1
Valid 12Z Thu Jun 11 2026 - 12Z Fri Jun 12 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE MIDWEST...

.Midwest to southern Plains...
Early this morning, a frontal wave developed over the central
Plains ahead of a strong upper level trough that will lift into the
Midwest today. This wave of low pressure is forecast to surge
northeast into the Midwest and be accompanied by an area of
enhanced convection in the vicinity of the low. A strengthening low
level jet on the leading edge of this disturbance will bring a
surge of moisture (PWAT values > 2 inches) and instability (MUCAPE

3000 J/kg) into the Midwest and create a sheared environment that

will allow for organized convection with highly efficient rainfall
rates up to 2-4 inches per hour. A Slight Risk of excessive
rainfall is in effect for portions of the Midwest where the hi-res
CAMs are showing the highest rainfall totals. There was some
consideration of upgrading to a Moderate Risk for portions of Iowa,
Wisconsin, and Illinois given recent heavy rains and soil
saturation, but the highest rainfall totals today are forecast to
be displaced to the north of where the heaviest rain fell on
Wednesday, which should keep the risk of flash flooding more in
line with a high-end Slight. On the backside of the frontal wave,
the cold front will surge southeast across the central and southern
Plains this afternoon with showers and storms expected to form
along the front. Given the highly moist and unstable environment on
the warm side of the boundary, these storms will be capable of
producing high rainfall rates, but the progressive nature of the
front should help limit the risk of flash flooding. A Marginal Risk
area extends back into the southern Plains where locally heavy
rainfall may lead to isolated instances of flash flooding.

.Ohio Valley to Mid-Atlantic...
An upper level shortwave trough is expected to move southeast
across the Ohio Valley and Mid-Atlantic today, which will provide
upper level support for the development of scattered showers and
storms this afternoon. Warm, moist air will be in place across
these regions, with PWAT values generally ranging from 1.75-2
inches, which will support rainfall rates of 1-2 inches. Elevated
instability (>2000 J/kg) should allow for some deeper convective
cells that will be capable of producing locally heavy rainfall.
Isolated instances of flash flooding will be possible, especially
if heavy rain occurs in urban environments, so there is a Marginal
Risk of excessive rainfall extending from the Ohio Valley to the
Mid-Atlantic. Northwesterly upslope flow will also result in
enhanced precipitation totals along the central Appalachians that
could create isolated flooding concerns in this region as well,
which is included in the Marginal Risk area.

.Southwest Florida...
Southeasterly flow has increased PWAT values above 2 inches across
Central and South Florida, which will allow for very heavy
rainfall rates of 2-4 inches per hour in convection along the sea
breeze boundaries this afternoon. Hi-res CAMs show the Atlantic and
Gulf sea breezes colliding over Southwest Florida, which could
result in flash flooding concerns for urban areas. Therefore, there
is a Marginal Risk of excessive rainfall for urban areas along the
west coast of the Florida Peninsula from Tampa south.

Dolan


Day 2
Valid 12Z Fri Jun 12 2026 - 12Z Sat Jun 13 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE SOUTHERN
PLAINS TO THE NORTHEAST AND FOR CENTRAL AND SOUTHWEST FLORIDA...

On Friday, an upper level trough will push across the Northeast and
drive a cold front across the eastern and south-central United
States. Scattered showers and storms are expected to develop as the
frontal boundary interacts with the anomalously warm and moist air
mass, and increased shear in the vicinity of the trough will
likely support some deeper organized convection in portions of the
Mid-Atlantic and Northeast. Moisture will pool ahead of the front,
and PWAT values are forecast to rise above 2 inches from the
southern Plains to the Northeast, which will allow for efficient
rainfall rates. Flash flood potential should be somewhat limited by
the speed of the front; however, locally heavy rainfall may lead
to isolated instances of flash flooding. Storms over the southern
Plains will move slower as the frontal boundary becomes quasi-
stationary, which may result in some areas of higher rainfall
totals. A mid-level wave is expected to move east across the
central/southern Plains Friday evening, which should lift the
frontal boundary north as a warm front and support a wave of
enhanced convection Friday night. There is still quite a bit of
uncertainty in where this area of convection will develop, but
there will likely be some enhanced flash flood potential over
portions of the central/southern Plains. Further southwest,
southeasterly flow and increasing moisture will support enhanced
showers and storms over West Texas and eastern New Mexico, which
may create flooding concerns in the vicinity of the Guadalupe and
Sacramento mountains and in burn scar areas. A Marginal Risk of
excessive rainfall stretches from the southern Plains to the
Northeast to cover these threats. Elsewhere, heavy rainfall will
also be possible in Florida where anomalous moisture will reside.
Convection along the sea breezes will have the potential to produce
very heavy rainfall that could lead to flooding concerns for urban
areas in Central and Southwest Florida. A Marginal Risk area has
been introduced to cover these threats.

Dolan


Day 3
Valid 12Z Sat Jun 13 2026 - 12Z Sun Jun 14 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
CENTRAL PLAINS AND MID/LOWER MISSISSIPPI VALLEY...

On Saturday, several features will come together to support a heavy
rainfall threat over the central United States. An upper level
trough will drop south into the central U.S. while several southern
stream waves move northeast into the Plains ahead of this feature.
At the surface, a warm front will lift across the south-central
U.S. while a cold front moves south across the north-central U.S.,
creating an area of strong convergence from the central Plains to
the Mid/Lower Mississippi Valley. In addition to strong synoptic
forcing, a very warm, moist, and unstable air mass will be in place,
which will support the development of numerous showers and storms
with efficient rainfall rates. These features should stall for a
period as they come together, resulting in an area of very heavy
rainfall. A Slight Risk is in effect where the heaviest rainfall
totals are expected from the central Plains to the Mid/Lower
Mississippi Valley. Locally heavy rainfall will also be possible in
showers and storms forming along the cold front in the Midwest,
and isolated flash flooding will be a concern, especially after
heavy rainfall expected on Day 1/Thursday. Locally heavy rainfall
may also be possible across West Texas and eastern New Mexico where southeasterly flow may support terrain induced precipitation. A
Marginal Risk of excessive rainfall surrounds the Slight and
extends from West Texas and eastern New Mexico to the Great Lakes.

Dolan


Day 4 and Day 5

Valid 12Z Sun Jun 14 2026 - 12Z Tue Jun 16 2026

...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS FOR PORTIONS OF THE
SOUTHERN PLAINS, LOWER MISSISSIPPI VALLEY, AND THE SOUTHEAST...

The overnight guidance continued to show a broad, amplifying trough
prevailing over over much of the eastern two-thirds of the CONUS
this period. As shortwave energy drops into the base of the
trough and further amplifies it, the associated frontal boundary
is expected to push well south into the southern Plains and lower
Mississippi Valley on Sunday. Increasing southerly flow from the
western Gulf will support deepening moisture along the front, while
upper level jet dynamics and mid-level energy provide areas of
enhanced ascent. Coinciding with the deepest moisture (PWs at or
above 2 inches) and some of the better forcing, a Slight Risk was
drawn on Day 4 from southeastern Oklahoma and northeastern Texas
over to central Mississippi. This is a southward adjustment from
the previous issuance given the overnight model trends in bringing
the front farther south.

Back to the north, low level upslope flow interacting with mid
level energy dropping into the broader scale trough is expected to
help initiate storms capable of producing locally heavy amounts
and isolated flash flooding concerns as far north as the Colorado
Rockies.

By Monday, the front is expected to move more slowly to the
south and east. As it does, moisture will continue to pool along
the boundary, with both the GFS and ECMWF showing PWs increasing
to over 2.25 inches (more than 2.5 std dev above normal) from South
Texas to southern Alabama. Given the potential for highly-
efficient, training showers and thunderstorms, heavy amounts and
flash flooding will be a likely concern across this area. A Slight
Risk was drawn where the latest guidance showed the greater
overlap between the deeper moisture and better forcing. Will
continue to monitor this area for potential upgrades, especially if
the model signal for heavy amounts continues to increase or show
successive days of heavy rainfall across the same areas.

Pereira
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 120808
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
408 AM EDT Fri Jun 12 2026

Day 1
Valid 12Z Fri Jun 12 2026 - 12Z Sat Jun 13 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FROM THE SOUTHERN
ROCKIES THROUGH THE MID-SOUTH, MID-ATLANTIC, AND NORTHEAST AS WELL
AS FOR CENTRAL AND SOUTHWEST FLORIDA...

...South-Central States through Northeast...

An upper trough over Michigan early this morning will shift east
across the Northeast through tonight. Prefrontal activity ahead of
the associated cold front persists over Lake Erie and the lower
Ohio Valley with stronger activity over the Oklahoma/Arkansas
border early this morning. Deep moist convection develops diurnally
today ahead of the cold front east of the Mid-South and a warm
front lifting over the southern Plains. An extensive Marginal Risk
remains from the southern Rockies/Sacramento and Davis Mtns across Texas/Oklahoma, the Mid-South/Tennessee Valley and over New
England. Some activity is still progged over the Central
Appalachians, so the Marginal Risk was maintained there, though it
is a notably low risk compared to northern New England and the
Tennessee Valley where PW anomalies are over 2 sigma (more like a
peak of 1.5 sigma in the Mid-Atlantic). Most of this activity will
be fairly progressive hence no Slight Risks at this time.

Some trimming of the north side to the Marginal Risk was made,
though timing tonight with surging Gulf moisture limits that
reduction, particularly based on the 06Z HRRR with central
Missouri activity late tonight.

...Central and Southwest Florida...
Anomalous moisture will reside over southwest and central portions
of the Florida Peninsula today, though it should be a little less
in terms of PW compared to Thursday. Convection along the sea
breezes should produce very heavy rainfall that could lead to
flooding concerns for urban areas in Central and Southwest Florida.
A Marginal Risk remains in effect with Tampa Bay removed due to CAM
consensus to the east/south of there.

Jackson


Day 2
Valid 12Z Sat Jun 13 2026 - 12Z Sun Jun 14 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
CENTRAL PLAINS THROUGH THE MIDDLE MISSISSIPPI VALLEY INTO THE
LOWER OHIO VALLEY...

An upper trough swings down the northern Plains Saturday, pushing a
cold front across the central Plains and Midwest through Saturday
night. Meanwhile, a warm front tracks from Oklahoma through
Illinois ahead of the cold front, creating focus for strong
convergence in a very warm, moist, and unstable air mass. Resultant
heavy thunderstorms look to organize and repeat from the central Kansas/Oklahoma border through central/southern Illinois and
western Kentucky where the Slight Risk was expanded a bit.
Particular focus for heavy rain remains near the Kansas/Missouri
border where a higher than normal Slight Risk is noted. Scattered
instances of flash flooding can be expected and a targeted Moderate
Risk is possible.

More isolated heavy thunderstorms are also expected over the
eastern New Mexico and west Texas terrain and nearby plains where
the Marginal Risk remains.

The Marginal Risk was removed from most of Michigan based on the
00Z high-res solutions available with little PW anomaly noted.

Jackson


Day 3
Valid 12Z Sun Jun 14 2026 - 12Z Mon Jun 15 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
TEXAS AND THE LOWER MISSISSIPPI VALLEY...

...Southern Rockies, Texas to Southeast...

A cold front pushes down the Southern Plains into Texas on Sunday.
This shunts the heavy rain focus south of Saturday and provides a
strong focus for convective development in a rich Gulf-sourced
moisture environment. PW anomalies are 2 to 3 sigma above normal
across Texas (south of the Panhandle) by that afternoon with 2
sigma anomalies expanding east to Alabama by late Sunday night.
Expansion of the Slight Risk to both North Texas and the Houston
metro areas are warranted given the environment as well as the 00Z
consensus of the UKMET and EC-AIFS for the Houston area, and the
RRFS and RDPS for North Texas. Furthermore, a decent signal for
lasting thunderstorm development is over West Texas in the Permian
Basin into the Concho Valley, so a Slight Risk was raised there as well.

Additional terrain driven diurnal activity is expected over the
Southern Rockies/Sacramento and Davis Mtns. This activity should
spread southeast through the evening, so the Marginal Risk was
expanded over the southern High Plains.

A surge of moisture up the southern Appalachians Sunday morning
brings enough of a heavy rain threat for a Marginal Risk expansion
up to the westernmost section of Virgina.

...Hampton Roads and Delmarva...
Southwesterly low level flow from the Carolinas bring 2" PW to the
Mid- Atlantic coast Sunday afternoon ahead of a cold frontal
passage that night. Evening thunderstorms should be heavy and slow
enough to warrant a Marginal Risk.

Jackson


Day 4 and Day 5

Valid 12Z Mon Jun 15 2026 - 12Z Wed Jun 17 2026

...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS FOR PORTIONS OF THE
SOUTHERN PLAINS, LOWER MISSISSIPPI VALLEY, AND THE SOUTHEAST...

Overall, not much change from the previous forecast, with the
overnight guidance continuing to present a good signal for highly-
efficient training storms along a slow-moving front settling into the region.

Models continue to show a cold front settling slowly south though
the southern Plains, lower Mississippi Valley, and the Southeast as
shortwave energy gradually amplifies a broad upper trough centered
along the Mississippi Valley on Monday. A deepening pool of
moisture along the front, fed by southerly low level inflow from
the western Gulf, will fuel the potential for highly-efficient
showers and storms. Guidance continues to show PWs increasing to
2.25 inches (2.5 to 3 std dev above normal) along and ahead the
front from south South Texas to southern Alabama on Monday.
Interacting with this moisture is expected to be an area of
enhanced ascent provided by right-entrance region upper jet forcing
positioned along the base of the amplifying trough. In addition to
the deep moisture and large-scale ascent, repeating storms are
expected to raise the potential for heavy amounts and flash
flooding concerns. A Slight Risk was maintained from southeastern
Texas to central and southern Alabama on Day 4.
By Tuesday, the upper trough axis begins to shift to the east,
pushing the front, deeper moisture, and the better chance for heavy
rain farther south and east along the Gulf Coast. For Day 5, a
Slight Risk was drawn from southeatern Lousiana to southwestern Georgia.

While Slight Risks were drawn for both periods, given the potential
for several inches of rain in some locations, an upgrade to a
Moderate Risk may be required in future updates if the signal
persists as the event draws nearer.

Pereira
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 130736
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
336 AM EDT Sat Jun 13 2026

Day 1
Valid 12Z Sat Jun 13 2026 - 12Z Sun Jun 14 2026

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR SOUTHWESTERN MISSOURI...

In coordination with SGF/Springfield, MO and EAX/Pleasant Hill, MO
forecast offices, the Moderate Risk was shifted south out of the
Kansas City metro with this update, but expanded southeast to cover
more of the Missouri Ozarks. CAMs guidance of the QPF footprint for
the day has followed a very common pattern, which is to shift the
heaviest rainfall totals southward. Thus, it appears the greatest
flash flooding threat has shifted out of the Kansas City metro.
This is most certainly not to say that the flooding threat has
reduced to zero for the Kansas City metro, which remains in a
higher-end Slight, but that the greatest impacts from flash
flooding due to heavy rainfall are no longer expected to reach
Moderate Risk thresholds in the Kansas City metro. However, not far
to the south, the threat remains significant.

Training thunderstorms are expected to begin across Missouri this
afternoon. The training and overall coverage of the thunderstorms
will increase during the evening with the usual diurnal
strengthening of the low-level jet. This will pump abundant
tropical moisture into Missouri from the southwest on 40+ kt winds
at 850 mb. Since the line of storms is expected to align northwest
to southeast, the storms will be orthogonal to that southwesterly
flow, which will be essential for the continued redevelopment and
training of additional convection as the cells within the line
track southeastward. Once the storms reach around the Arkansas
border, the low level jet weakens significantly. This should allow
for breaks to develop in the line from Arkansas into Tennessee,
which will greatly diminish the flash flooding threat in those
states. The topography of the Ozarks across southern Missouri
supports a heightened flash flooding threat as the mountains
quickly funnel the heaviest rains into narrow valleys, worsening
the impacts of any flooding that develops there. This fact too
supports the southeastward expansion of the Moderate Risk area.

Meanwhile, a strong cold front will push southeastward out of the
Plains and eventually into Missouri. This front will end all of the
rain from northwest to southeast. This too supports the south and
eastward shifting of the greatest flash flooding threat. While
portions of far eastern Kansas still will have a threat for
extended periods of heavy rain, the advancing front reaching those
areas before points further east should also reduce the time heavy
rain will impact eastern Kansas, allowing for the Moderate to be
trimmed a bit. That said, there remains considerable uncertainty as
to how far east the best lines of training thunderstorms will set
up, so far eastern Kansas remains in an elevated threat for flash flooding.

Guidance has come into better agreement that the heaviest rains
will occur over Missouri today and tonight, and will struggle to
continue further north and east. Thus, the inherited Slight Risk
area over Iowa, most of northern Illinois, and all but the
southwestern tip of Indiana was downgraded to a Marginal Risk with
this update.

...Florida...

A Marginal Risk area was introduced with this update for all of the
Florida Peninsula. Abundant moisture and slow-moving thunderstorms
are expected to develop all up and down the Peninsula this
afternoon. Since the storms will be stationary, it stands to reason
that the most heavily impacted areas will see extended periods of
heavy rain. HREF neighborhood probabilities for over 3 inches of
rain are over 70% for the entire Peninsula. Thus, while the urban
areas on both east and west coasts are more flood-prone and are
likely to miss out on the heaviest rains, any urban areas such as
Orlando in the middle of the Peninsula could have isolated
instances of flash flooding.

Wegman


Day 2
Valid 12Z Sun Jun 14 2026 - 12Z Mon Jun 15 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR AREAS FROM
SOUTHERN NEW MEXICO THROUGH WESTERN MISSISSIPPI...

A slow-moving but potent cold front will approach portions of north
Texas through into Arkansas on Sunday. The MCS that caused the
Moderate Risk flooding in Missouri Saturday night will be
responsible for the heavy rains that elevate northeast Texas
through the lower Mississippi Valley into the Slight Risk
category. Associated heavy rain will be ongoing at the start of the
period Sunday morning, and will weaken and dissipate by midday.
Since the forward/southward progression of the heavies rains will
slow after daybreak Sunday, some areas may see several hours of
weakening but still heavy rains. Abundant moisture will remain in
place south of the front, as PWATs rise as high as 2.25 inches.
Thus, any cells producing rains will have no trouble doing so
efficiently. During the afternoon and evening, this area may see
additional widely scattered storms with the strong front stalled
out in the area, but coverage will be somewhat in question as the
stalled out front alone will not be enough forcing due to flow on
either side of the front weakening to light and variable winds.

Further west into west Texas and New Mexico, a shortwave trough
running into some of the same Gulf moisture as further east should
allow for scattered showers and thunderstorms to develop in
clusters from the afternoon well into the evening. Topographic
assistance by the Sacramento Mountains and other ranges may locally
produce heavy rains, where any burn scars may take over at raising
the flash flooding risk. The same front extends into the
Appalachians and interior Northeast. While the storms will be
racing in these areas, the abundance of moisture advecting north
into the front will support the storms in their capability of
producing heavy rainfall. The Marginal Risk for these areas was
expanded along the Canadian border through northern Maine.

The Marginal for portions of the Mid-Atlantic was split into 2
areas with this update. One for the I-95 corridor from DC to
Philly, and a second for the Hampton Roads area. Abundant
Gulf/Atlantic moisture in these areas will support fast-moving but
training storms capable of producing heavy downpours. Due to
ongoing drought, the threat really is focused on the urban areas
where FFGs are lower. The intermediate rural areas were removed
with this update as any training storms that occur over most of the
Delmarva will be over rural and flood-resistant/flat areas.

Wegman


Day 3
Valid 12Z Mon Jun 15 2026 - 12Z Tue Jun 16 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
LOWER Mississippi VALLEY TO EASTERN TEXAS...

A large, half-continent sized upper level low over northern Ontario
will spin numerous shortwaves around its periphery over the eastern
2/3 of the country. The jet stream will coincide with a strong but
stalled out cold front over north Texas and southern Arkansas. To
the south of that front, Gulf moisture will pool to well-above
normal levels, with PWATs to 2.25 inches over east Texas and
northern Louisiana. When the shortwaves track over that cold front,
it will both allow it to continue drifting southward, but also
provide sufficient upper level forcing to trigger numerous and
persistent thunderstorms along the east-west oriented front and
south. This will support an extended duration of training storms,
especially from east Texas through southwest Mississippi. A
higher-end Slight remains in effect for this area. The inherited
Slight was trimmed out of south-central Texas and central Alabama
on the west and east ends, but expanded north-south over Louisiana
through the Houston Metro. Rainfall totals in some areas could
easily exceed 6 inches, with totals to 10 inches in localized areas
possible due to the extended duration of heavy rain, especially
along the Texas/Louisiana border. The area remains in a higher end
Slight for now primarily due to very high FFGs and dry soils in the
area, but further increases in rainfall, especially as this period
moves into the CAMs range, could allow for a Moderate Risk upgrade
due to the very high rainfall amounts forecast for some areas.

Wegman


Day 4 and Day 5

Valid 12Z Tue Jun 16 2026 - 12Z Thu Jun 18 2026

...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS FOR PORTIONS OF THE
CENTRAL GULF COAST...

The first half of the medium range will see two particular threats
for flash flooding. First, along the Gulf Coast, a stationary
front will work in tandem with with tropical moisture to develop
thunderstorms capable of torrential downpours both on Day 4
(Tuesday) and Day 5 (Wednesday). There is greater confidence in
Tuesday's flash flood threat given better model agreement in
placement of QPF and the nearby frontal boundary remaining strong
enough to help trigger numerous showers and thunderstorms. PWs
will remain above 2.0" in many cases as well, allowing developing
thunderstorms to contain highly efficient rainfall rates. Soils
will be more saturated in wake of Monday's thunderstorms as well,
making the region more susceptible to flash flooding. The forecast
remains largely on track for Tuesday (Day 4) with only some minor
tweaks to the inherited Marginal and Slight Risks to more closely
resemble the latest WPC QPF. By Wednesday (Day 5) the frontal
boundary will undergo frontolysis and the source of lift at the
surface will weaken. However, ensemble guidance continues to show
ample tropical moisture along the Central Gulf Coast, which at by
Wednesday will have dealt with multiple rounds of Excessive
Rainfall. A Marginal Risk was introduced along the I-10 corridor
from the Houston metro on east to the FL Panhandle to account for
the flash flood potential around the more urbanized communities
along the central Gulf Coast.

Farther north, Wednesday looks like an active day from the Midwest
on east into the OH Valley. A 500mb shortwave trough racing east
towards the Great Lakes late Wednesday will provide healthy upper-
level ascent aloft to foster the development of low pressure.
Meanwhile, a strengthening LLJ will direct anomalous moisture
located over the South northward into the region. NAEFS shows an
impressive IVT for mid-June that surpasses 750 kg/m/s over the
eastern Corn Belt that will provide copious amounts of moisture.
Guidance is not in agreement yet as to which locations are most
favored to witness the heaviest thunderstorm activity. Fast storm
motions should also help to limit residency times of developing
storms. That said, PWs ranging between 1.75-2.0" will be the norm
late Wednesday with storms likely containing efficient rainfall
rates. A Marginal Risk was introduced to account for the localized
flash flood potential on Wednesday from the Middle MS River on east
into the OH Valley.

Mullinax
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 261558
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1158 AM EDT Fri Jun 26 2026

Day 1 Valid 16Z Fri Jun 26 2026 - 12Z Sat Jun 27 2026

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL IN EFFECT FROM
NORTHEAST OKLAHOMA THROUGH SOUTH-CENTRAL MISSOURI...

...Southern Plains to the Mid-Atlantic...

16Z Update...Upgraded to Moderate for northeast Oklahoma, far
southeast Kansas, much of southern Missouri, and extreme northern Arkansas.

Initial impulse over southeast MO this morning will continue
shifting east to the Mid-Atlantic through tonight. Earlier activity
south of a lingering stationary front has worked over southern
IN for the time being, so an upgrade from Slight is not necessary
there through central WV.

The next impulse is over the KS/CO border and cross KS through this
evening before crossing southern MO overnight. This is the concern
that warranted the upgrade to Moderate. Saturated soils, PW
increasing to around 2" on a robust LLJ tonight, and increasing
instability into the evening. 12Z CAMs are united in a risk for
3-5" rainfall in a few hours from organized activity through the Moderate area.

Expanded the Marginal east again through the central Mid-Atlantic
where the presence of 70F dew points and maintained instability
overnight near a boundary is often sufficient for prolonged
overnight activity and at least localized flash flooding.

...Montana into North Dakota...

Deep low pressure center shifts from the British Columbia coast to
Washington through tonight with associated shortwave troughing
lifting through Montana. Strong steering flow will keep activity
progressive, but the environment for organized convection with
potential for training exists. Moisture looks sufficient with
precipitable water anomalies of 1.5 sigma above normal. Corridors
of 1-2" rainfall, locally 3" are likely over central MT through
central ND where the Marginal remains in place (expanded west just
a bit in MT).

...Central High Plains...

Increased troughing over the Great Basin promotes return flow up
the High Plains with evening convective activity off the Sangre de
Cristos and Front Range that spills onto the central High Plains
through the night. The risk for repeating cells in a moist
environment with precipitable water anomalies some 1.5 sigma above climatological average which still warrants a Marginal Risk for
the central High Plains, now connecting to the farther east risk
over south-central KS/western OK.

...Northern New England...

Shortwave low moving through Quebec will allow a trough axis to
swing through New England through this afternoon. Sufficient
instability and mid-level forcing from the disturbance and diurnal
heating should lead to enhanced thunderstorms capable of producing
1-3" of rainfall across northern New England. Repeating activity
could allow localized flash flooding despite moisture being
limited. More of central VT/NH was added with less eastern Maine
based on the 12Z HRRR.

Jackson/Bann


Day 2 Valid 12Z Sat Jun 27 2026 - 12Z Sun Jun 28 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE NORTHERN PLAINS AND A PORTION OF THE OHIO AND TENNESSEE VALLEYS...

...Ohio Valley...

The Slight Risk was shifted a bit farther south than the previous
outlook to match the better the placement of moisture pooling and
upper level support. The previous expansion still looked good based
on the latest suite of deterministic and ensemble suite of QPF
combined with the wet antecedent conditions there.

...Mid-Atlantic...

Ongoing activity Saturday morning looks to settle over eastern
VA/the Delmarva by Saturday afternoon with a risk for localized flash flooding.

...Northern Plains...

Energy shedding along with shortwave energy embedded withing the
broader flow around a deep upper trough will locally enhance
rainfall amounts that may lead to isolated flash flooding over the
Northern Plains Saturday afternoon and evening....especially in
any supercell cores and multi-cell mergers that transpire once the
LLJ kicks in after 00Z. Given an increase of higher amounts
clipping a portion of the international border region...opted for a
targeted Slight risk area in parts of eastern Montana and North Dakota.

Bann


Day 3 Valid 12Z Sun Jun 28 2026 - 12Z Mon Jun 29 2026

The probability of rainfall exceeding flash flood guidance is less
than 5 percent.

Bann


Day 4 and Day 5 Valid 12Z Mon Jun 29 2026 - 12Z Wed Jul 01 2026

Day 4

...The probability of rainfall exceeding flash flood guidance
values is less than 5 percent...

Oravec

Day 5

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS THE
SOUTHERN HIGH PLAINS, UPPER MISSISSIPPI VALLEY/UPPER LAKES REGION
AND ACROSS NORTHERN NY STATE INTO NORTHERN NEW ENGLAND...

...Northern New York State into Northern New England...
Westerly low level flow expected to strengthen into the frontal
boundary forecast to stretch northwest to southeast from eastern
Ontario into northern NY State and northern New England late Tue
afternoon into Tuesday night. There is potential for organized
convection in the 0000 to 1200 UTC July 1 period along and north of
this boundary. The GFS and EC both show PW values becoming very
anomalous along and just north of this front, with values 2.5-3+
standard deviation above the mean. While there is still a lot of
spread with qpf details at this time range, there is a model signal
for organized convection moving northwest to southeast resulting
in heavy rains and isolated runoff issues.

...Southern High Plains...
PW values expected to rise to 1 to 1.5+ standard deviations above
the mean in the broad southwest mid to upper level flow across the
Southern High Plains on the west side of the Lower MS closed upper
high. Embedded shortwaves in this southwest mid to upper level flow
will support increasingly scattered convection in this high PW
axis, with locally heavy rains and isolated runoff issues.

...Upper MS Valley...
Convection expected to become increasingly active late Tue
afternoon into Tue night/early hours of Wed along and ahead of the
surface front moving slowly across the Upper MS Valley. Favorable
right entrance region jet dynamics ahead of this front in an axis
of above average PW values will support potential for heavy rains
with organized convection along and ahead of this cold front with
isolated runoff issues possible.

Oravec
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)

FOUS30 KWBC 270829
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
429 AM EDT Sat Jun 27 2026

Day 1 Valid 12Z Sat Jun 27 2026 - 12Z Sun Jun 28 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE NORTHERN PLAINS AND FROM THE MID MNISSISSIPPI VALLEY TO THE
SOUTHERN APPALACHIANS...

...Mid-Mississippi Valley through Southern Appalachians...

Another expansion of a high-end Slight Risk area was made along a
west to east axis based on convection occurring prior to the start
of the outlook period at 27/12Z...with the expectation that the
risk persists through much of the Day 1 period in proximity to an
east-west oriented stationary front. Low level westerly flow
remains parallel to this boundary, raising concerns for
repeating/training activity. The 27/00Z HRRR and the 27/00 RRFS QPF
placement was similar to each other...but the RRFS appeared to be
showings its bias with higher QPF and higher neighborhood
probabilities of exceedance. The concern is greatest upon overlap
of any additional rainfall with the footprint of recent heavy
rainfall events.

...Mid-Atlantic...

00Z guidance offered a split decision of whether or not a frontal
zone lingers over the central Mid- Atlantic through tonight rather
than shifting shifting south to the Virginia/North Carolina border.
Assuming it stays over the Mid-Atlantic...enhanced moisture and
instability will remain over the DC area metros and the DelMarVa
with a risk of isolated heavy to excessive rainfall otherwise the
focus shifts south with time. Despite that uncertainty...any
storms that form in such an airmass can easily produce localized
downpours and excessive rainfall. This still looks to be a
localized flash flood threat, but a focused Slight Risk may be
needed eventually.

...Northern Plains...

The upper low tracks over the interior Northwest on today with a
shortwave troughing ejecting across northern Wyoming and eastern
Montana by this evening. Low level forcing east of the approaching
wave triggers repeating thunderstorms over eastern Montana through
North Dakota from this afternoon into the evening. Increasing Low
Level Jet should enhance rainfall within the Slight Risk
maintained/expanded eastward in North Dakota. Activity should be
fairly progressive, but the route of the upper trough may
pivot/allow repeating activity.

Bann/Jackson


Day 2 Valid 12Z Sun Jun 28 2026 - 12Z Mon Jun 29 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL IN NORTHWEST
MONTANA AND PORTIONS OF THE UPPER MIDWEST...

...Montana...

Upper low center pivots over Montana Sunday with the surface low
stalling along the international border . This maintains comma
head/deformation zone rain shifting into northwest MT where terrain
enhances rates at lower elevations and snow generally at or above
6500 feet. This is more of an areal flood concern given a lack of
instability, but localized rates may warrant some rapid flooding
concerns where precip bands are most stagnant. 00Z consensus
rainfall remained in the 1 to 3 inch range around Glacier National
Park onto the adjacent high plains in northwest MT. A marginal
risk was maintained for this area.

...Upper Midwest...

The warm sector of this anomalous low over MT will shift eastward
allowing an airmass with robust Gulf moisture advection up the
length of the Great Plains through the Upper Midwest. The
development of surface low pressure over South Dakota will aid the
moisture transport at the low levels and provide a lifting
mechanism. Focusing on this...there was an eastward expansion and a
bit of a southward expansion of the previously issued Marginal risk area.

...Coastal Carolinas/Mid-Atlantic...

Added a small, targeted Marginal along the eastern seaboard where
precipitation lingers from the Day 1 period. Blending disparate QPF
in such cases tends to yield low amounts...but the area had the
best overlap with highest precipitable water values and an area
where ensemble members with differing cores tended to cluster. With
such high moisture...localized downpours and heavy to excessive
rainfall is a concern from any storm that can develop regardless of
the meager focusing mechanism.

Bann/Jackson


Day 3 Valid 12Z Mon Jun 29 2026 - 12Z Tue Jun 30 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PORTIONS OF
THE GREAT LAKES REGION AND SOUTHWEST TEXAS...

Great Lakes...

Shifted the Marginal Risk area from Day 2 eastward into the western
portion of the Great Lakes region as the feed of low level
moisture from the Plains shifts in association with the parent
system. Given recent conditions...only problems are expected in
regions of poor drainage or small streams.

Southwest Texas...
Increasing instability should lead to late day convective
development along and near the dry line in southwest Texas.
Isolated heavy rainfall may result as moisture from the Gulf gets
drawn northwestward in time...with a low end potential for
excessive rainfall associated with the most active convection.

Bann


Day 4 and Day 5 Valid 12Z Tue Jun 30 2026 - 12Z Thu Jul 02 2026

Day 4

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS THE
SOUTHERN HIGH PLAINS, UPPER MISSISSIPPI VALLEY/UPPER LAKES REGION
AND ACROSS NORTHERN NY STATE INTO NORTHERN NEW ENGLAND...

...Northern New York State into Northern New England...
Shortwave energy riding up over the top of the Ohio Valley upper
high across southeast Canada into northern New England will help
strengthen the low level westerly flow into the frontal boundary
forecast to stretch northwest to southeast from eastern Ontario
into northern NY State and northern New England late Tue afternoon
into Tuesday night. There is potential for organized convection in
the 0000 to 1200 UTC July 1 period along and north of this
boundary. The GFS and EC continue to both show PW values becoming
very anomalous along and just north of this front, with values
2.5-3+ standard deviation above the mean. While there is still a
lot of spread with qpf details at this time range, there is a model
signal for organized convection moving northwest to southeast
resulting in heavy rains and isolated runoff issues.

...Southern High Plains...
PW values expected to rise to 1 to 1.5+ standard deviations above
the mean in the broad southwest mid to upper level flow across the
Southern High Plains on the west side of the Lower MS closed upper
high. Embedded shortwaves in this southwest mid to upper level flow
will support increasingly scattered convection in this high PW
axis, with locally heavy rains and isolated runoff issues.

...Upper MS Valley/Upper Lakes...
Convection expected to become increasingly active late Tue
afternoon into Tue night/early hours of Wed along and ahead of the
surface front moving slowly across the Upper MS Valley. Favorable
right entrance region jet dynamics ahead of this front in an axis
of above average PW values will support potential for heavy rains
with organized convection along and ahead of this cold front with
isolated runoff issues possible.

Oravec

Day 5

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL THE UPPER
MISSISSIPPI VALLEY/UPPER LAKES REGION AND ACROSS NORTHERN NY STATE
INTO NORTHERN NEW ENGLAND...

...Northern New York State into Northern New England...
Similar to the day 4 time period, additional shortwave energy is
expect to ride along the top of the Ohio Valley closed upper high
across southeast Canada into northern NY State and New England
during day 5. These height falls will be accompanied by another
area of anomalous PW values, 2 to 3 standard deviations above the
mean, pushing out of southeast Ontario and southern QB into
northern NY State and northern New England. While there is the
typical amount of spread with qpf details, there is a signal for
additional organized convection moving in a northwest to southeast
direction across northern NY State into northern New England,
supporting heavy rains and localized runoff issues, especially in
areas of training.

...Upper MS Valley/Upper Lakes...
Another round of shortwave energy pushing northeastward from the
Central Plains into the Upper MS Valley/Upper Lakes region will
support another round of potentially organized frontal/pre-frontal
convection late Wednesday into early Thursday across these regions.
.The GFS and EC both show PW values becoming anomalous in the
vicinity of this front late Wednesday into early Thursday,
supporting heavy rain potential and isolated runoff issues. The
marginal risk was drawn to encompass the typical amount of spread
in the guidance at this time range.

Oravec
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/10)