MD 1950 CONCERNING HEAVY SNOW FOR SOUTH-CENTRAL IL…WEST-CENTRAL IN
Mesoscale Discussion 1950
NWS Storm Prediction Center Norman OK
0330 AM CST Sat Nov 12 2022
Areas affected...south-central IL...west-central IN
Concerning...Heavy snow
Valid 120930Z - 121300Z
SUMMARY...Heavy snowfall rates (near 1 inch/hour for 1 to 2 hours)
are expected in a frontogenetic band centered around 650 mb near the
I-70 corridor through 13 UTC.
DISCUSSION...Radar mosaic shows a band of moderate to heavy snow
located from Belleville, IL extending east-northeast to Mattoon, IL
as of 0930 UTC. Scott AFB in Belleville, IL measured a 1.25
inch/hour rate between 0730-0830 UTC and heavy snow (1/8 mi
visibility) was reported through 0855 UTC. The 06 UTC NAM appears
to be capturing the placement of the snowfall band with
frontogenesis in the 600-700 mb layer. The frontogenetic
contribution and the large-scale ascent (DCVA) provided by the
approach of the mid-level shortwave trough over the MO Ozarks will
combine to enhance ascent and boost snowfall rates in a mesoscale
corridor (near I-70). The NAM shifts the frontogenetic forcing into
west-central IN during the 1100-1300 UTC period and the rates will
coincidentally taper over IL.
..Smith.. 11/12/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IND...ILX...LSX...
LAT...LON 38529012 39228929 39768714 39688662 39388648 39218683
39148782 38888870 38378952 38378987 38529012
