Mesoscale Discussion 0179
NWS Storm Prediction Center Norman OK
0209 PM CST Wed Feb 23 2022
Areas affected...parts of southeast Missouri...southern
Illinois...extreme western Kentucky...extreme western Tennessee
Concerning...Winter mixed precipitation
Valid 232009Z - 240115Z
SUMMARY...Wintry mixed precipitation, mainly in the form of moderate
to heavy sleet, is expected to overspread portions of the Mid
Mississippi Valley through the afternoon. Brief bouts of locally
higher freezing rain rates may occur along the Missouri/Tennessee
border where surface-925 mb temperatures are higher compared to
points farther north.
DISCUSSION...MRMS mosaic radar data depicts a large swath of wintry
mixed precipitation with embedded isolated to scattered
thunderstorms progressing across southern MO/northern AR in tandem
with the 850-700 mb warm-air/moisture advection axis. The 16Z LZK
observed sounding depicted around 250 J/kg MUCAPE in association
with the WAA regime, and this buoyancy should continue to stream east-northeastward, fostering continued development of elevated
convection and locally higher freezing rain/sleet rates roughly from
the MO Bootheel and points south and east. Farther north, 925 mb CAA
beneath the warm nose should provide ample low-level cooling for a
moderate to heavy sleet threat with the approaching precipitation
band through the afternoon.