Mesoscale Precipitation Discussion 0130
NWS Weather Prediction Center College Park MD
644 PM EDT Sat Apr 05 2025

Areas affected...Southeast Texas and Southwest Louisiana

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

Valid 052244Z - 060430Z

SUMMARY...Inflow convection into the much more robust showers and
storms over northern Louisiana has been intensifying over the past
few hours. Daily record precipitable water in the column is
supporting convection with very efficient warm-rain processes.
Localized rainfall rates to 2 inches per hour are expected. Flash
flooding is possible, especially in urban areas, small streams and
creeks, and other flood-prone, low-lying areas.

DISCUSSION...An impressive low level jet is advecting incredibly
moist air from the Gulf northward on 40-45 kt southerly winds from
925 through 850 mb. This has pushed PWATs into record territory at
Lake Charles. The storms are being driven by a very slow moving
upper level low and associated surface cold front that are
providing ample lift to support storms that have been producing
rainfall rates to 2 inches per hour near and just northeast of
Houston. This surface based convection will continue into the
evening hours as none of the ingredients supporting very heavy
rainfall will be abating. Further, recent heavy rainfall across
the bayous of Louisiana have lowered the thresholds needed for
flooding caused by these storms as they slowly track east across
far southeast Texas and southwest Louisiana.

CAMs guidance has struggled by underdoing both the coverage and
rainfall intensity of these storms so far. However, there is
reasonable agreement that the heaviest rainfall over the next 6
hours (for southeast Texas and southwest Louisiana) will be across
the southeasternmost counties in Texas and the southwesternmost
parishes of Louisiana. Additional inflow convection may develop
further east towards central Louisiana and Baton Rouge later
tonight in response to the eastward movement of the convection
further north, but there's considerably more uncertainty for the
eastern half of the MPD area.

Given the storms from Houston north and east have developed into a
training pattern with additional storms forming on the front edge
of the line near Houston, this pattern of training is likely to
continue into the evening hours given the very slow movement of
the parent cold front causing these heaviest storms. Flash
flooding is possible with these training storms, especially in
southeast Texas closest to the heaviest storms. Impacts are most
likely in urban areas around and the eastern suburbs of Houston,
in already full streams and creeks, and flood-prone low-lying
areas.

Wegman

ATTN...WFO...HGX...JAN...LCH...LIX...SHV...

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

LAT...LON   31909174 31829127 31619117 30809146 30139184
            29549215 29579267 29769335 29629425 29169496
            29459553 29979542 30519524 30859508 31239487
            31579467 31579464 31449396 31549321 31859239