181
AWUS01 KWNH 280916
FFGMPD
TXZ000-OKZ000-281500-

Mesoscale Precipitation Discussion 0336
NWS Weather Prediction Center College Park MD
514 AM EDT Tue May 28 2024

Areas affected...southwestern OK into North TX

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

Valid 280900Z - 281500Z

Summary...Heavy showers and thunderstorms will continue to produce
1-3"/hr rainfall rates through mid to late morning, resulting in
localized totals of 3-6". Isolated to scattered flash flooding is
likely.

Discussion...Heavy showers and thunderstorms are becoming more
organized along and near the Red River of the South (TX/OK border
region) early this morning, following recent backbuilding in the
vicinity of right-movers that emerged from earlier splitting
supercells. This has already resulted in some localized totals of
2-4" in the region, but additional backbuilding and training of
cells is expected to result in an increase in coverage and
severity of flash flooding into late morning. The mesoscale
environment is highly favorable for additional upscale growth of
convective activity, given ample instability (MUCAPE of 2000-5000
J/kg), tropospheric moisture (PWATs of 1.2-1.5 inches, near the
90th percentile per FWD sounding climatology), and shear
(effective bulk shear of 45-55 kts). This parameter space should
have no trouble continuing to support rainfall rates of 1-3"/hr.

While a couple HREF members (ARW and NAM-nest) have a depiction of
convection in this region this morning, even those members were
far too slow and weak compared to observational trends (while the
other members didn`t even manage to initiate convection). The HRRR
has come around in the past couple of runs (06z/07z) after
insisting on suppressed convection from earlier runs. While the
coverage and amounts are likely still at least a bit underdone
(indicating localized totals of 2-3" in a limited area of North TX
through 15z), the general QPF footprint and storm evolution
matches that of the HREF PMM, indicating additional upscale growth
towards the southeast via upwind propagation towards the higher
instability (and focused along and near a quasi-stationary surface
boundary). This puts the Dallas-Forth Worth metroplex in the cross
hairs of this mornings activity, increasing concerns for flash
flooding (given the sensitivities of the urbanized terrain and
higher population centers). Given the highly favorable
observational trends (and the unreliability of the hi-res
guidance), isolated to scattered instances of flash flooding are
likely through late morning (with 3-6 hour FFGS generally 2-4").
Should these higher totals occur across the DFW metroplex, some
flash flooding could be locally significant (as 3-hr FFGs locally
as low as 1.5").

Churchill

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

ATTN...WFO...AMA...FWD...LUB...OUN...SHV...

ATTN...RFC...ABRFC...LMRFC...WGRFC...NWC...

LAT...LON   35279874 34919731 34309630 33329564 32479529
            32249650 32729746 33489851 34860025