331
AWUS01 KWNH 082357
FFGMPD
LAZ000-ARZ000-TXZ000-OKZ000-090530-

Mesoscale Precipitation Discussion 0624
NWS Weather Prediction Center College Park MD
757 PM EDT Tue Jul 08 2025

Areas affected...Southeast Oklahoma, The ArkLaTex, North Texas

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

Valid 082356Z - 090530Z

Summary...Showers and thunderstorms will expand across the
ArkLaTex and North Texas through the evening. Rainfall rates of
2-3"/hr are likely within deeper convection, leading to 2-3" of
rain with locally higher amounts. Flash flooding is possible.

Discussion...The regional radar mosaic this afternoon shows two
outflow boundaries (OFB) draped in the vicinity of the ArkLaTex.
One is moving south along the Red River Valley, while a second OFB
lifts slowly northward across eastern Texas. Aloft, a shortwave is
noted in WV imagery drifting south across Oklahoma, while
impressive upper divergence pivots overhead to additionally
enhance ascent. Across this region, PWs above 2.2 inches exist in
a ribbon oriented SW to NE, collocated with a corridor of MLCAPE
above 2500 J/kg. Convection forming along these OFBs is already
producing radar-estimated rain rates of 1.5+"/hr according to KSHV.

During the next few hours, it is likely that these OFBs will
collide. The interaction of these boundaries will occur into the
core of the most impressive thermodynamics, and beneath the most
aggressive upper divergence, suggesting rapid convective growth
along the convergence axis. The CAMs, while differing in exact
timing and placement of this collision, all indicate an
intensifying west-to-east oriented swath of convection during this
collision, providing higher confidence in the evolution. With
robust thermodynamics in place, this intense ascent will result in
strong updrafts which could support rainfall rates of 2-3"/hr as
forecast by HREF neighborhood probabilities for 2"/hr reaching
40%. These thunderstorms will also likely move very slowly as
0-6km mean winds are just 5-10 kts, with modest bulk shear of
around 20 kts marginally supporting convective clusters. Where
these develop, they may train from west to east along the
boundary, at least briefly, lengthening the duration to produce an
axis of 2-3" of rain with locally higher amounts approaching 5"
possible.

This area has been dry recently, which is reflected by FFG as much
as 3-4"/3hrs, except SW of the Dallas metro and west of I-35 where
FFG is considerably lower. The HREF exceedance probabilities for
this FFG peak only around 20%, suggesting the flash flood risk
will be generally isolated through the evening. However, with slow
moving storms containing these intense rain rates, and the
increasing potential for some upwind propagation along the
colliding boundaries to slow the net motions, soils could be
locally overwhelmed, especially in urban areas or atop the locally
more saturated areas, leading to instances of flash flooding.

Weiss

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

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

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

LAT...LON   34419463 34339328 34039251 33339225 32749261
            32249344 31849481 31619622 31419741 31499874
            31849882 33239777 34369636