Mesoscale Precipitation Discussion 0422
NWS Weather Prediction Center College Park MD
1107 PM EDT Wed Jun 11 2025

Areas affected...central TX

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

Valid 120304Z - 120730Z

Summary...Areas of heavy rain from slow moving thunderstorms are
likely to produce scattered areas of flash flooding across
portions of central TX through 07Z. The threat of flash flooding
is expected to increase toward the south with time and a few spots
of 3 to 6+ inches may lead to significant/considerable impacts.

Discussion...GOES East water vapor imagery showed the southern end
of a mid to upper-level low over west-central TX along the
northern end of the Edwards Plateau near the Colorado River at
0230Z. Radar imagery showed scattered thunderstorms from the
Edwards Plateau, northward to I-20 and as far east as I-35. MRMS
hourly rainfall was topping out near near 4 inches just north of
Waco while other cells to the west of I-35 and near I-20 showed
peak hourly rainfall of 1-2 inches. The environment as sampled by
the 00Z FWD RAOB and depicted on the 02Z SPC mesooanalysis showed
modest mid-level lapse rates of 6.2 C/km, tall/skinny CAPE with
500-1500 J/kg mixed layer instability and PWs that ranged from 1.7
to 1.9 inches across the region. The 00Z FWD sounding also showed
a wet-bulb zero height of 12.6 kft, indicative of the potential
for warm rain processes.

Over the next 3-5 hours, the southern lobe of the mid-level low
will slowly edge east while 925-850 mb layer flow increases from
southern to eastern TX into the 20 to 30+ kt range. Slow moving
cells will continue across the region with the slowest motions
closest to the mid-level low/trough placement...west of the
Metroplex to just north of the Edwards Plateau. By 06Z (1 AM CDT),
the increasing magnitude of the low level flow and low level
convergence along its leading edge should allow for expanding
convective development to focus farther south	toward San Antonio
while slowly expanding east across the I-35 corridor. Cells will
show a mixture of slow movement, back-building/training and
merging which will be capable of 2 to 3+ in/hr rainfall.

Given recent heavy rain and the expectation of localized
additional totals of 3 to 6+ inches through 07Z to 08Z, scattered
areas of flash flooding will be likely. 01Z and 02Z WoFS indicated
the greatest potential for 3+ inches of rain over the following 6
hours to be from near San Antonio, northward to just west of
Austin (50-80 percent probs). In addition, 90th percentile data
(reasonable worst case scenario) showed 10 to 12 inches of rain in
some of these same locations. While 10 to 12 inches of rain may be
a high bar to reach, even 50th percentile QPF values of 4-5 inches
from the WoFS is noteworthy. These rains may lead to locally
significant/considerable flash flood impacts, especially given the
sensitive terrain of the TX Hill Country.

Otto

ATTN...WFO...CRP...EWX...FWD...HGX...SJT...

ATTN...RFC...FWR...NWC...

LAT...LON   33139750 32209651 30479643 29239715 28719821
            28699924 29249992 30859989 32009901 32969858