Mesoscale Discussion 0085
NWS Storm Prediction Center Norman OK
0702 PM CST Wed Feb 21 2018
Areas affected...far northern Oklahoma to central/eastern Kansas
Concerning...Winter mixed precipitation
Valid 220102Z - 220500Z
SUMMARY...Pockets of freezing rain, mixing with sleet, will continue
to develop across the region this evening. Freezing rain rates up to
a few hundredths of an inch per hour will be possible.
DISCUSSION...Within the entrance region of a powerful upper-level
jet, showery activity has developed from the Texas Panhandle
northeastward to the Wichita, KS metro. 00Z soundings from AMA, OUN,
DDC, and TOP all depict a 700-500mb thermal structure potentially
supportive of weak mid-level buoyancy, such that very shallow
convection is expected to persist this evening. Additionally, weak
warm advection and related isentropic ascent near 850-700mb will
further support the development of precipitation.
Related to this elevated warm advection, model guidance and
mesoanalysis data depict a slow north/northwestward progression of
the 850mb 0C line over the next several hours, and this is confirmed
by a northward advance of a melting layer signature noted in KICT
data. Along the northern fringe of the discussion area, sleet may be
more common. Farther south, freezing rain potential will be higher,
although some mixing with sleet may still occur, especially in
heavier showers that favor re-freezing in the boundary layer.
Regardless, freezing rain rates up to a few hundredths of an inch
per hour will be possible into the early overnight, with freezing
drizzle possible outside of heavier precipitation.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 38359828 38819739 39029546 38939516 38609511 38259555
37399681 36729748 36479796 36289874 36589898 36969903