AWUS01 KWNH 030700
FFGMPD
TXZ000-031300-

Mesoscale Precipitation Discussion 0967
NWS Weather Prediction Center College Park MD
300 AM EDT Tue Sep 03 2024

Areas affected...South-Central to Central to Northwest Texas...

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

Valid 030700Z - 031300Z

SUMMARY...Widely scattered flash flooding remains possible with
shallow, slow moving showers crossing compromised soil conditions.

DISCUSSION...GOES-E WV suite depicts a closed low at the base of a
WSW to ENE Westerlies trough axis over the northern portion of the
West Texas Panhandle with the mean trough extending toward the
southern Big Country where a strengthening MCV continues to lift
north-northeast into Northwest Texas.  Broad transverse banding
along the northern semi-circle of the wave depicts solid
outflow/divergence aloft to strengthen the wave supporting
slantwise ascent across the Hill country thought the 700-500mb
layer into the broad right entrance.   This north-south axis
through the Hill country and Triangle of central Texas is also the
leading edge of the northern extension of the easterly wave
crossing eastern Texas.  Behind the wave, surface to 850mb flow is
strengthening with a SW-NE axis of increased theta-E/unstable air
that is defined well in the TPW/MUCAPE fields from RAP analysis.=20
As this enhanced moisture/unstable air reaches the Hill country
and the mid to upper-level divergent/slantwise ascent pattern;
expect additional shallow topped showers to develop into west to
east banded like features before slowing and turning northward
into the mid-level trof from the exiting shortwave feature.=20=20

While dynamic forcing/cell motions are favorable for
convergence/slow motions across northern South-central TX into the
Hill country, instability is fairly limited with gradient of
MUCAPE of 500-1000 J/kg generally along and south of 32N.  As
such, convection is likely to remain scattered and shallow in
nature.  However, given the bulk of the high total moisture
content is in the lowest layers (15kft), moisture loading and warm
cloud processes will allow for efficient rainfall rates, but
unless training occurs, hourly totals are probable to remain below
1-1.5".=20

However, rainfall throughout the area today has resulted in solid
infiltration with NASA SPoRT 0-40cm relative soil moisture ratios
increasing into the 70-80% range; and FFG values have crashed to
below 1.5"/hr with broad areas of sub .5"/hr rates across the
northern Hill country into the southern Big Country today.  So
while the entire area is not likely to experience scattered 1"
totals through the next 6 hours, an isolated spot of 3-4" is
possible; but it will not take much for above average run-off with
these intense sub-hourly/instantaneous rain rates with warm cloud
processes.  As such, widely scattered to scattered focused areas
of flash flooding will be expected through the late
overnight/early morning hours.

Gallina

...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!7PTksmae3A08yZDZ2KHL_szOV_zDSQmBbS8EDY9KOUa5YC068mugv4twt548W-kak-vQ=
r4o2V9Aeqv2dvb2tIWoimQk$  for graphic product...

ATTN...WFO...EWX...FWD...LUB...MAF...SJT...

ATTN...RFC...WGRFC...NWC...

LAT...LON   33379809 33249739 32929687 32569688 31959761=20
            31219827 30999837 29659853 29039936 28940075=20
            30230147 31510146 32450093 33040034 33329944=20
=20=20=20=20=20=20=20=20=20=20=20=20

=3D =3D =3D
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