876
AWUS01 KWNH 310313
FFGMPD
TXZ000-310910-

Mesoscale Precipitation Discussion 0354
NWS Weather Prediction Center College Park MD
1112 PM EDT Thu May 30 2024

Areas affected...Portions of Western and Central TX

Concerning...Heavy rainfall...Flash flooding possible

Valid 310310Z - 310910Z

SUMMARY...Multiple convective clusters will tend to grow upscale
overnight. Locally very heavy rainfall rates and some localized
training of cells may favor scattered instances of flash flooding.

DISCUSSION...The 00Z surface analysis shows a quasi-stationary
front draped generally west to east across western and central TX,
with GOES-E IR satellite imagery showing multiple cold-topped
convective clusters focusing along it. The latest RAP analysis
shows a substantial amount of instability pooled along the
boundary with MLCAPE values of as much as 2000 to 3000 J/kg, and
moist/convergent 850 mb flow of 20 to 30 kts. Meanwhile, a rather
well-defined outflow boundary is situated south of the front from
portions of the Edwards Plateau eastward down into the southeast
TX coastal plain.

Shortwave energy ejecting out across the southern High Plains will
be interacting with the original synoptic front and the outflow
boundary overnight, and with the favorable thermodynamic
environment, a general increase in the coverage of convection is
expected. The low-level jet is forecast to have some nocturnal
enhancement to upwards of 30 to 40+ kts going toward 06Z and
beyond. Effective bulk shear values of 40 to 50 kts are forecast
to be in place, and this coupled with the instability should yield
organized convective clusters near the front with some tendency to
forward propagate. Some localized training of cells will be
possible as well.

PWs downstream of the current convective activity across central
TX are locally over 1.5 inches which is a solid 2 standard
deviations above normal, and this moist environment will favor
high rainfall rates that may locally reach 1.5" to 2.5"/hour
overnight with the stronger and more organized cells.

The 00Z HREF guidance is in poor agreement with the details of the
convective evolution tonight, and is already not handling any of
the ongoing activity across western/central TX well. However, the
experimental WoFS does depict a more reasonable depiction of the
ongoing activity and evolution moving forward near the
aforementioned boundaries. The expectation is for as much as 3 to
5 inches of rain locally where any cells tend to repeat or train
over the same area. Scattered instances of flash flooding will be
possible where the stronger convective cells/clusters focus.

Orrison

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

ATTN...WFO...FWD...LUB...MAF...OUN...SJT...

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

LAT...LON   33509839 33399725 32989642 32299599 31549630
            31169712 31349893 32010054 32470153 32850165
            33230091 33479962