AWUS01 KWNH 221111
FFGMPD
OKZ000-KSZ000-221630-

Mesoscale Precipitation Discussion 1109
NWS Weather Prediction Center College Park MD
710 AM EDT Sat Aug 22 2026

Areas affected...Central Oklahoma...South-Central Kansas...

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

Valid 221110Z - 221630Z

SUMMARY...Narrow band of slow moving elevated storms with
favorable orientation for possible repeating along the I-35
corridor places a few urban centers at risk of possible localized
flash flooding this morning.

DISCUSSION...GOES-E 10.3um and regional RADAR shows expanding line
of scattered cooling tops oriented favorably along/near the I-35
corridor from south-central KS into Central OK. Tops have been
cooling fairly quickly nearing -70C aligned with core of deep
layer moisture but also conditionally unstable air with spine of
2000 J/kg MUCAPE and 1.5-1.75" total PWat. CIRA LPW animation of
Sfc-850 and 850-700mb layers show this weakly curved arc of
enhanced moisture. Low level flow is generally parallel to the
band through 850mb, though 700mb westerly flow is more orthogonal
to the moisture/instability axis likely convergent near the base
of the elevated instability within the vertical profile to seed
the scattered development. Low level southerly to
south-southwesterly inflow response likely further helped to
deepen the vertical depth of the cells, so given the shear though
the layer; cell motions have been slow.

Additionally, while the RAP shows some modest divergence aloft,
animation of GOES-E WV shows a very tight anticyclonic ridge axis
through western OK; likely providing greater than analyzed
divergence for further vertical ascent and outflow for some weak
organization and maintenance of the updrafts. So many conditional
elements have come together for greater than forecast convective
development this morning per Hi-Res CAM suite. While the 09z RRFS
has backed off, the 06z run was more in line with this evolution
and given the natural bias of the RRFS to be a bit more aggressive
with convective initiation in a capped environment (relative to
other CAMs, esp. the HRRR), this seems to be a solution to provide
some guidance in the near-term.

Given the instability, rates and 15-20kts of 700mb flow (as well
as southerly 20+kts of boundary layer inflow), moisture flux is
supporting 1.75-2"/hr rates. However, the weak inflow and veered
profile does hint at weaker overall deep layer convergence, so
updrafts are a bit narrower than ideal for repeating training.
Still, the 700-400mb steering flow along the shortwave ridging in
W OK, may allow for some locations for repeating, though slow cell
motions will likely be the best way to result in increased
residency for spots of 2-4" totals. Given the recent dry
conditions FFG values are higher with exception of north-central
OK where 3hr values are 2-2.5" compared to 3-4"+ further south.
Still, the placement of the line is nearly directly along I-35 and
places larger urban centers in proximity from Wichita to Ponca
City/Stillwater into the Edmond/OKC/Norman areas. So, if ideal training/repeating can align, these will be the areas of greatest
localized flash flooding potential this morning.

Gallina

ATTN...WFO...ICT...OUN...TSA...

ATTN...RFC...TUA...NWC...

LAT...LON 38439827 38119752 36419658 35169636 34199677
33989742 34339778 35449759 36679785 37479818
38149842

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