AWUS01 KWNH 221301
FFGMPD
ARZ000-TXZ000-OKZ000-221740-

Mesoscale Precipitation Discussion 1116
NWS Weather Prediction Center College Park MD
900 AM EDT Mon Sep 22 2025

Areas affected...eastern OK into central/northern AR

Concerning...Heavy rainfall...Flash flooding likely

Valid 221259Z - 221740Z

SUMMARY...Continued training of showers and thunderstorms will
maintain an increased potential for flash flooding from portions
of eastern OK into central/northern AR over the next 3-5 hours.
Hourly rainfall will range from 1 to 3 inches.

DISCUSSION...Radar imagery from 1230Z showed an ongoing cluster of
thunderstorms over north-central AR, in the vicinity of I-40 to
the west of Little Rock. This area has been associated with
MRMS-derived hourly rainfall of 1 to 3 inches since at least 10Z
within areas of training. A second small cluster was located just
north of Dallas/Fort Worth while additional shower/thunderstorm
activity was developing over eastern OK. All of these areas were
located just north of an effective quasi-stationary front draped
from AR WSW into northern TX enforced by rain-cooled outflow. VAD
wind plots across the region highlighted 850 mb wind speeds of
20-30 kt from the SW across TX into AR but with veering toward the
WSW over TX since 10Z. Meanwhile, SPC mesoanalysis data from 12Z
indicated MLCAPE of 1000-1500 J/kg along and north and just north
of the effective front with short term RAP forecasts showing
weakening inhibition over eastern OK over the next few hours with
the onset of daytime heating and continued low level moisture
advection into the region.

Short term RAP forecasts are in line with weakening of the low
level jet through 18Z but the boundary will remain and some degree
of overrunning should continue over the next few hours with a
strongly favorable diffluent/divergent region aloft over AR ahead
of a sub-tropical jet max over KS/OK. Some expansion of
shower/thunderstorm activity is expected over eastern OK over the
next 1-2 hours with potential for training within the mean
westerly steering flow. Given the high precipitable water
environment (1.5 to 2.0 inches) and sufficient instability,
pockets of training are likely to continue at least localized
areas of flash flooding over the next 1-2 hours with possible
continuation of the flash flood threat through 17Z, though
confidence beyond the next 1-2 hours is lower than average given
poor model handling of the ongoing activity.

Otto

ATTN...WFO...FWD...LZK...MEG...OUN...SHV...TSA...

ATTN...RFC...FWR...ORN...TUA...NWC...

LAT...LON   36049368 35959248 35739092 35419054 34569097 
            34409275 34289423 33669526 32999622 33179711 
            33599726 34759684 35579603 35999493 

$$
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