498
AWUS01 KWNH 050937
FFGMPD
TXZ000-051305-

Mesoscale Precipitation Discussion 0595
NWS Weather Prediction Center College Park MD
536 AM EDT Sat Jul 05 2025

Areas affected...central TX

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

Valid 050935Z - 051305Z

SUMMARY...The potential for locally catastrophic flash flooding is
expected to continue over the next few hours over central TX,
extending through sunrise. Extreme hourly rainfall near and in
excess of 4 to 5 inches can be expected at times. Dangerous /
life-threatening flash flooding is already occurring and will
continue for at least another 2-4 hours.

DISCUSSION...0915Z radar imagery showed that a small cluster of
heavy rain continued to affect central TX, with the highest
rainfall intensities over western Williamson and eastern Burnet
counties. Gauge data from the Lower Colorado River Authority
(LCRA) showed a 10.34 inch total in 3 hours ending 0910Z, 8 miles
SSW of Betram as recent trends in radar imagery have shown the
heaviest rainfall intensities shifting northward compared to a few
hours ago. This northward shift appears to be tied to a northward
translation of a west-east oriented instability gradient that
bisected the small convective cluster. Latent heat release within
the thunderstorm cluster has reinvigorated a mesoscale vortex
which was located along the Burnet/Williamson county line and has
been allowing for the development of new updrafts to its immediate
north, following 20-30 kt of southerly 925-850 mb winds within the
anomalous PW environment (2.0 to 2.2 inches per 09Z SPC
mesoanalysis data).

Some continued northward development is expected over the next 2-4
hours, although the core of the heaviest rain near the MCV is
likely to remain farther south. While there is some uncertainty in
the duration of the heaviest rainfall with RAP forecasts of
925-850 mb winds shifting east and weakening through 13Z,
continued very high rainfall rates of 3 to 5+ inches in an hour
are expected to persist for another 1-3 hours with additional
rainfall of 5 to 10 inches possible on top of an already saturated
and flooded region just west of I-35. These rains are likely to
continue threats for locally catastrophic flooding across a small
region of central TX through at least 12Z.

Otto

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

ATTN...WFO...EWX...FWD...SJT...

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

LAT...LON   32449795 32349756 31969740 31059754 30429784
            30359821 30599847 31019866 31549866 32099853
            32359819