AWUS01 KWNH 051200
FFGMPD
LAZ000-TXZ000-051757-

Mesoscale Precipitation Discussion 0977
NWS Weather Prediction Center College Park MD
759 AM EDT Thu Sep 05 2024

Areas affected...southern Louisiana, far southeast Texas

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

Valid 051157Z - 051757Z

Summary...A gradual increase in flash flood potential should occur
through the early afternoon.

Discussion...A relatively focused band of convection extends along
the south Louisiana coastline from south of Lake Charles to near
Houma, with more scattered convection located just offshore over
the far northern Gulf of Mexico. The convection was tied to a
weak low centered just southeast of Galveston, with low-level
confluence, 2.6+ inch PW values, abundant buoyancy (2000 J/kg
MLCAPE - located mainly offshore), and weak steering flow aloft
all supporting locally heavy rainfall with rates exceeding 2-3
inch/hr at times. Over the past hour, most of the heavier rain
rates were located south/southeast of Galveston and with slow
northward-moving convection near Houma. Furthermore, storms near
Houma are oriented a bit more favorably for training/repeating,
potentially supporting extreme rain rates in that area.

Over time, both models and observations suggest a gradual increase
in convection over land areas. This increase will likely be tied
to both northward trajectories of cells from the Gulf and inland
development of stronger buoyancy - perhaps reaching the I-10/12
corridor later this morning as insolation/heating increases. This
should result in at least a few areas of excessive rainfall
through the morning, with typical sensitive/low-lying and urban
areas experiencing the greater flash flood threat through 18Z/1p
CDT and probably beyond.

Cook

ATTN...WFO...HGX...LCH...LIX...

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

LAT...LON 30399080 30118938 29548893 29048909 28849033
29279209 29129478 29229510 29939453 30369318

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AWUS01 KWNH 131117
FFGMPD
LAZ000-TXZ000-131716-

Mesoscale Precipitation Discussion 0427
NWS Weather Prediction Center College Park MD
717 AM EDT Fri Jun 13 2025

Areas affected...southern Louisiana, far southeast Texas

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

Valid 131116Z - 131716Z

Summary...A cluster of slow-moving storms have produced estimated
4-6 inch rainfall totals near Lafayette, Louisiana this morning.
This cluster is expected to very slowly evolve within a very
unstable airmass, posing a risk for flash flooding through
17Z/noon CDT.

Discussion...Scattered thunderstorms have managed to evolve into a
persistent, slow-moving cluster near Lafayette this morning. The
storms are embedded in deep south-southwesterly steering flow of
around 20-25 knots, but have managed to backbuild locally due to
1) confluent 850mb wind fields evident via objective analyses, 2)
a weak surface boundary extending from near Galveston, TX
east-northeastward through Lafayette to near Hammond, LA, and 3)
strong instability/weak inhibition along and south of that subtle
boundary. Impressive moisture/instability content within the
pre-convective airmass (2000 J/kg MLCAPE, 2 inch PW values) were
contributing to impressive local rain rates exceeding 2.5
inches/hr at times. With 4-6 inches of rain having already
fallen, some impacts are likely with the ongoing activity in the
short term.

Through 17Z/noon CDT, the reinforcement of a surface/outflow
boundary near the convection (due to cold pool formation) will
likely enable continued development and training of cells. Some
propagation of this cluster is expected, and both westward and
eastward development of storms toward areas near Lake Charles and
near/south of Baton Rouge can be expected. Another 3-5 inches of
rainfall can be expected beneath the heavier, slower-moving
thunderstorm bands as well. Locally higher amounts cannot be
ruled out in a few spots.

Cook
ATTN...WFO...HGX...LCH...LIX...

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

LAT...LON 30509132 30289060 29989016 29599001 29229034
29169115 29539237 29659388 29469442 29779450
30179381 30479252

$$
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