Mesoscale Precipitation Discussion 0162
NWS Weather Prediction Center College Park MD
1258 PM EDT Thu Apr 18 2024

Areas affected...southeastern Arkansas, western Mississippi, and
northeastern Louisiana

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

Valid 181657Z - 182100Z

Summary...Localized flash flood threat continues across the
discussion area through 21Z.

Discussion...A robust band of training convection continues along
the AR/LA border region near/just north of an axis from Lake
Providence to Bastrop.  Radar estimates of 3-5 inches of rainfall
have been observed with this band so far.  Surface observations
suggest that a maturing cold pool has developed in vicinity of the
storms, which should aid in a continued focus for convective
development through the early afternoon.  Meanwhile, southwesterly
850mb flow continues to help maintain a fetch of 1500+ J/kg SBCAPE
and 1.8 inch PW values into the region, supporting robust and
efficient updrafts.  Upstream, satellite/radar imagery continues
to suggest updrafts near/east of Shreveport, likely associated
with a mid-level shortwave trough near TXK.  This suggests that
continued development of convection will likely continue for at
least a couple more hours (potentially through 21Z) on the western
flank of ongoing convection.  At least 1 inch/hr rain rates are
likely to be maintained during this period.

Models and observations suggest that the overall scenario
supporting flash flooding should shift to the east at some point -
especially once the shortwave trough over the TXK area shifts
eastward and mid/upper subsidence can develop in its wake.  This
process will take a few hours to unfold, however.  Flash flooding
potential will continue - especially where heavier rainfall has
already occurred across the discussion area.

Cook

ATTN...WFO...JAN...LZK...MEG...SHV...

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

LAT...LON   33939112 33849012 33348978 32649024 32509183
            32399281 33319293 33739223