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