MD 1952 CONCERNING HEAVY SNOW FOR SOUTH-CENTRAL AND SOUTHWESTERN OK
Mesoscale Discussion 1952
NWS Storm Prediction Center Norman OK
1141 AM CST Mon Nov 14 2022
Areas affected...south-central and southwestern OK
Concerning...Heavy snow
Valid 141741Z - 142045Z
SUMMARY...Heavy snow with rates near 1 inch per hour will continue
across west-central OK this afternoon, and possibly spread
east-southeastward across south-central OK in the next few hours.
DISCUSSION...Latest water vapor loops show strong DCVA overspreading
western OK ahead of a compact midlevel shortwave trough approaching
west TX. Cold/saturated deep-layer thermodynamic profiles over west
TX (sampled by the 12z AMA observed sounding) coupled with the
strengthening large-scale ascent are supporting areas of heavy snow
across parts of western OK. As the DCVA continues to overspread a
weak ENE-WSW-oriented midlevel thermal gradient across this area,
frontogenetic forcing should aid in a somewhat focused corridor of
snowfall rates near 1 inch per hour given a modestly deep and
saturated dendritic growth zone. However, mesoscale ascent is not
particularly strong here, so confidence in prolonged heavy rates in
any given area is limited at this time. Over southwest OK, surface
temperatures remain above freezing, though continued showers and
related moistening of the boundary-layer should yield a transition
to snow during the next couple hours.
Farther east, regional VWP data depicts an increasing southerly
low-level jet over north-central TX which will gradually impinge on
a WSW-ENE-oriented low/mid-level baroclinic zone over south-central
OK. As the aforementioned shortwave trough continues eastward this
afternoon, strong mesoscale ascent -- aided by the larger-scale
ascent -- will develop through this corridor by 20Z. This
strong/focused ascent would conditionally support snowfall rates of
1 inch per hour (locally higher) for a few hours this afternoon. The
main question across this corridor is the degree of surface cooling,
as surface temperatures remain in the middle/upper 30s F. However,
current indications are that continued wet-bulb cooling and descent
of the melting layer could support additional surface cooling and a
band of heavy snow.
..Weinman.. 11/14/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OUN...
LAT...LON 34959961 35719972 36049958 36209929 36209904 36089869
35469854 35199802 34779698 34519703 34589752 34639816
34739874 34809923 34959961
