AWUS01 KWNH 091213
FFGMPD
TNZ000-KYZ000-ILZ000-MOZ000-ARZ000-KSZ000-091700-

Mesoscale Precipitation Discussion 0651
NWS Weather Prediction Center College Park MD
812 AM EDT Thu Jul 09 2026

Areas affected...Missouri southeast into Arkanas and Illinois

Concerning...Heavy rainfall...Flash flooding possible

Valid 091211Z - 091700Z

Summary...Showers and thunderstorms will continue to push
east-southeast across Missouri this morning with 1-2"/hr rainfall
rates. Flash flooding is possible.

Discussion...The regional radar mosaic early this morning shows an
area of rainfall with embedded thunderstorms expanding across
west-central MO. This activity is developing downstream of a
convectively enhanced shortwave and concomitant MCV noted via a
swirl in reflectivity just east of Kansas City. Aloft, modest
diffluence from the distant RRQ of a departing jet streak is
additionally providing ascent while the LLJ, measured via VWPs of
20-30 kts, is gradually veering out of OK/AR. PWs across MO as
analyzed by the SPC RAP are above 1.75 inches, with a plume of
MUCAPE exceeding 2000 J/kg also present. The most robust
thermodynamics, as reflected by the overlap of greatest PWs and
MUCAPE, are spread across SW MO, from which the LLJ is
originating, leading to persistent thermodynamic advection to
support heavy rainfall.

MRMS hourly rainfall has been as high as 1.5" recently, suggesting
the environment remains favorable for heavy rain producing
convection. The high-res CAMs suggest that this activity should
wane quickly in the next few hours, but they are also not
initializing the ongoing activity very well, with radar much more
aggressive than simulated reflectivity from the models. Although
the LLJ will continue to veer, and thus become less favorable for moisture/instability transport, the environment should remain
favorable for heavy rainfall, and the ingredients suggest the
guidance is too rapid to wane heavy rainfall this morning.
Additionally, the presence of the shortwave/MCV will create
sufficient ascent to not only drive lift but also locally
accelerate and back the LLJ, providing a focus for heavy rain
along any boundaries and convergence axes.

The HREF and REFS both suggest that 1"/hr rain rates will dwindle
in the next 2 hours, but this is likely too quick, so expect
several more hours with 1"/hr rain rates to move southeast across
MO towards AR/Il/TN. Although storm motions should remain elevated
around 15 kts to the southeast, repeating rounds along the NW to
SE oriented CAPE gradient and downstream of the MCV should allow
for pockets of 2-3" of rainfall which could locally exceed FFG
leading to instances of flash flooding through late morning.


Weiss

ATTN...WFO...EAX...LSX...LZK...MEG...PAH...SGF...

ATTN...RFC...KRF...MSR...ORN...NWC...

LAT...LON 39829494 39699363 39149221 38338991 37458904
36878906 35908983 35579057 35799133 36399252
36569271 37189343 37719405 38519485

$$
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