Mesoscale Precipitation Discussion 0615
NWS Weather Prediction Center College Park MD
444 PM EDT Wed Aug 08 2018
Areas affected...Central and Southern Arkansas
Concerning...Heavy rainfall...Flash flooding possible
Valid 082043Z - 090143Z
Summary....A localized flash flood threat exists through the
afternoon hours across portions of central and southern Arkansas.
Discussion...Convection continues to expand in coverage this
afternoon across portions of central and southern Arkansas. This
activity is developing within a highly unstable and moist airmass,
with MLCAPE values between 2000-3000 J/KG and PWs exceeding 2".
This overlap of instability and moisture is supportive of
efficient heavy rainfall producers over the next several hours.
In general this activity is forward propagating enough that the
duration of heaviest rates has been limited. With that said, there
is likely enough development that at least some cell mergers are
probable, locally extending the duration of heavier rates. Thus
while amounts in the 1-2" range are most likely, localized 3"+
amounts are possible through the afternoon hours. The heaviest of
this activity appears to be focused just south of areas that were
recently hit hard over central Arkansas. However, still some
chance that some of these areas get clipped over the next few
hours. Thus anticipate a localized flash flood risk both where
cells merge, and where rain overlaps the lower flash flood
guidance over the harder hit areas of central Arkansas.
Chenard
ATTN...WFO...LZK...SHV...
ATTN...RFC...ABRFC...LMRFC...
LAT...LON 35259235 35149174 35029148 34439129 33779146
33419256 33439306 33649358 33929378 34329372
34699346 34949305 35129272
Last Updated: 444 PM EDT Wed Aug 08 2018