328
AWUS01 KWNH 121334
FFGMPD
ARZ000-OKZ000-121732-

Mesoscale Precipitation Discussion 0656
NWS Weather Prediction Center College Park MD
933 AM EDT Sat Jul 12 2025

Areas affected...Eastern OK

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

Valid 121332Z - 121732Z

Summary...Localized heavy rainfall from slow moving thunderstorms
will result in a continued isolated flash flood risk through mid
morning across portions of eastern Oklahoma.

Discussion...Recent radar and satellite imagery shows continued
thunderstorm activity across eastern OK. This area is in between a
few MCV features...with one over MO, one over the TX Panhandle and
another over southwest KS. High res model guidance is not handling
this activity well, although the 11z and 12z HRRR finally have
some indication of this convection. HRRR forecast soundings
suggest this activity is based around 750-800mb, with models
struggling with the degree of saturation and convergence at this
level. Convection has been initiating near a cloud line seen in
satellite imagery trailing southwest from the MCV feature over MO.
This was likely indicative of some lower to mid level convergence,
which combined with a modest increase in elevated moisture and
possible weak vort max over eastern OK, has likely resulted in the
convective development.

The lack of useful model guidance does lower confidence on
convective evolution this morning. There is plenty of instability
(around 2000 j/kg of MUCAPE) to sustain convection and PWs around
1.8" supports heavy rainfall rates. Eventually the approach of the
stronger MCV from the west will likely result in additional robust
convective development by later today...however for the morning
hours forcing is weaker. Thus any slight drying around 800mb or
downtick in convergence would result in a weakening of convection.
Thus it seems most likely that convection will gradually weaken by
mid to late morning, before additional development occurs later
today...but again confidence on this evolution is only average.

In the meantime, the environment does favor slow cell motions...so
even though the storm cores are quite small...localized heavy
rainfall rates/totals will remain likely for the next couple
hours. The activity is pretty high based, and the degree of
lighting indicates sufficient ice in the cloud layer. Thus while
the most efficient warm rain processes are probably not dominant
in these cells...the high PWs and slow motions will still support
hourly rainfall as high as 2", and total rainfall of 3-4" in
spots. This will be enough to result in at least an isolated flash
flood risk this morning...especially in any more sensitive urban
areas.

Chenard

...Please see www.wpc.ncep.noaa.gov for graphic product...

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

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

LAT...LON   36449697 36399611 36239552 36169488 36009445
            35829428 35719440 35579476 35529538 35659611
            35709641 35849698 36149712