Mesoscale Precipitation Discussion 0089
NWS Weather Prediction Center College Park MD
1157 AM EST Fri Mar 08 2024

Areas affected...central Louisiana, central/southern Mississippi,
and central/southern Alabama

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

Valid 081657Z - 082257Z

Summary...An elongated MCS was becoming more favorably oriented
for training and flash flooding.  A few areas could experience 3-5
inch rainfall totals within this MCS through 23Z.

Discussion...In the wake of a lead bow/MCS now entering portions
of central AL (near TCL), an elongated axis of convection has
emerged from near MEI to JAN to ESF.  Additional convection was
located along a cold front from near SHV to LFK that was moving
eastward toward the ongoing axis of heavy rainfall.  In the past
30-60 minutes, areas of 1-2 inch/hr rain rates have developed
especially near and southwest of JAN.  This was occurring in
response to a couple of factors: 1) a slowly southward-moving
outflow boundary across central Mississippi, 2) fast
west-southwesterly steering flow aloft oriented parallel to
ongoing convection, and 3) very moist, unstable conditions (1000
J/kg SBCAPE, 1.8 inch PW values) that were feeding the updrafts
and contributing to efficient rainfall processes.

Through 23Z, expectations are that heavier rainfall axes will
focus along the outflow boundary, which should remain stationary
or move very slowly southward this afternoon especially across
Mississippi.  Training and cell mergers along this boundary should
allow for areas of 2 inch/hr rainfall totals to continue to
materialize, and storm totals as high as 5 inches could occur
through 23Z.  The magnitude of the rainfall should exceed FFG
thresholds and cause scattered areas of flash flooding to develop
(locally significant).  This threat may eventually spread into
southwestern Alabama after 20Z.

Farther upstream across Louisiana, training convection remains
likely along the nearly stationary boundary extending from north
of AQV to north of HEZ, although FFGs are slightly higher in these
locales compared to farther east.  Still, a few instances of flash
flooding are possible especially in low-lying areas and beneath
training cells.

Cook

ATTN...WFO...BMX...JAN...LCH...LIX...MOB...SHV...

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

LAT...LON   33228686 32478608 31428622 30748870 30619182
            31559339 32019282 32609136 33188857