282
AWUS01 KWNH 302209
FFGMPD
LAZ000-TXZ000-310315-

Mesoscale Precipitation Discussion 0350
NWS Weather Prediction Center College Park MD
608 PM EDT Thu May 30 2024

Areas affected...Southeast Texas...Southwest Louisiana

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

Valid 302210Z - 310315Z

SUMMARY...Squall line continues to accelerate but crossing fairly
saturated soils.  Sub-hourly 1-2" totals may pose possible flash
flooding conditions through this evening.

DISCUSSION...RADAR and GOES-E Vis/IR denotes a strong/mature
squall line starting to accelerate across northeast TX into
eastern TX.  Stronger cells exist along the southwest edge of the
complex and have access to greatest unstable air with solid
gradient of CAPE across the area of concern with MLCAPE values of
3000 J/kg along the SW edge to a bit more stable 1500-2000 J/kg
near the stationary front that bisects LA from SE to NW.  Very
moist environment off the Western Gulf per CIRA LPW shows near 1"
between surface and 850mb with Tds in the low to mid-70s; and
totals near 2". This will allow for strong updrafts to maintain on
the leading edge with HRRR 15 minute rain totals of 1.5"+ forecast
and up to 2.5"/hr as the line passes.

This alone would not infiltrate into average saturation soils, but
NASA SPoRT LIS 0-40cm remain in the upper 90th percentile with
65-75% saturation across much of the area of concern especially
across Polk county TX to Calcasieu/Beauregard parish...suggesting
nearly hydrophobic soils with potential of very high runoff and
localized flash flooding possible this evening.  Flash flooding
would be more likely if the cells were not expected to further
increase in speed and reach areas a bit more stabilized by this
morning`s activity; still the risk remains

Gallina

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

ATTN...WFO...FWD...HGX...LCH...SHV...

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

LAT...LON   32499316 32149243 30949241 30269312 30329472
            30699668 31449734 31999503