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000
AWUS01 KWNH 181413
FFGMPD
MSZ000-LAZ000-ARZ000-181812-

Mesoscale Precipitation Discussion 0161
NWS Weather Prediction Center College Park MD
1012 AM EDT Thu Apr 18 2024

Areas affected...northern Louisiana, southern Arkansas, and
western Mississippi

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

Valid 181412Z - 181812Z

Summary...A band of convection has deepened very near the
Arkansas/Louisiana border region over the past hour.  These cells
are oriented favorably for training and heavy rainfall,
potentially posing a spotty flash flood risk through 18Z.

Discussion...The combination of confluent/convergent low-level
flow (in the 850mb layer) and a stout shortwave trough across
northeast Texas was contributing to development of robust
convection along the AR/LA border region over the past hour.  The
cells are oriented favorably parallel to mid/upper steering flow
for training, and while rain rates so far are peaking at around
0.5 inch/hr, ~2000 J/kg SBCAPE and 1.5 inch PW values should
eventually support higher rain rates especially as convection
continues to train across the area.

Observations and SPC Mesoanalyses suggest that this axis of
convection could persist for a few hours as 1) the mid-level wave
providing ascent continues to approach the area and 2) convergence
on the nose of a 35kt 850mb low-level jet upstream across
southeast Texas both contribute to ascent for deep convective
development through 18Z or so.  An isolated flash flood risk is
expected especially where convective training can boost rain rates
into the 2-2.5 inch/hr range.  FFGs are in the ~2.5 inch/hr range,
and may be exceeded in a few spots as storms mature.

Cook

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

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

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

LAT...LON   33989137 33959011 33588961 32948967 32369123
            32229317 32589377 33189367 33609325 33889245