From Mike Powell@618:250/1 to All on Sun Aug 31 08:32:11 2025
AWUS01 KWNH 310942
FFGMPD
TXZ000-311540-
Mesoscale Precipitation Discussion 1037
NWS Weather Prediction Center College Park MD
540 AM EDT Sun Aug 31 2025
Areas affected...Portions of Central and Eastern TX
Concerning...Heavy rainfall...Flash flooding possible
Valid 310940Z - 311540Z
SUMMARY...A gradual increase in shower and some thunderstorm
activity is expected over the next few hours. High rainfall rates
and concerns for areas of cell-training will pose a threat for
isolated to scattered areas of flash flooding this morning.
DISCUSSION...Radar and satellite imagery early this morning is
showing a gradual increase in shower and thunderstorm activity
across portions of central and eastern TX. The convection which is
notably elevated in nature to the north of a stationary front is
being facilitated by a gradual increase in warm air advection
along with an uptick in low-level moisture convergence. MUCAPE
values are on the order of about 500 to 1000 J/kg.
Some additional expansion of convection is expected going through
the morning hours as some weakly divergent flow aloft along with
modestly convergent low-level flow in the 925/850 mb layer
interacts with the available pool of instability. The environment
is very moist with PWs of 2.0 to 2.2 inches and this should
support convection with high rainfall rates capable of reaching
1.5 to 2.5 inches/hour.
Rather slow cell-motions given the weak mean layer steering flow
coupled with the linear nature of some of the elevated convection
will potentially result in some rather heavy rainfall totals at
least locally this morning. Areas where any cell-training occurs
may see as much as 3 to 5 inches of rain given the deep moist
environment, and these rains will be enough to result in concerns
for isolated to scattered areas of flash flooding.