SPC MD 1748

MD 1748 CONCERNING HEAVY SNOW FOR NORTH CENTRAL SOUTH DAKOTA...SOUTHERN NORTH DAKOTA AND WEST CENTRAL MINNESOTA

Mesoscale Discussion 1748
NWS Storm Prediction Center Norman OK
0956 PM CDT Wed Oct 21 2020

Areas affected...north central South Dakota...southern North Dakota
and west central Minnesota

Concerning...Heavy snow 

Valid 220256Z - 220600Z

SUMMARY...Periods of heavy snow with rates of 1 to 2 inches per hour
appear likely across portions of the Dakotas and western Minnesota
tonight.

DISCUSSION...00z observed soundings and evening water vapor imagery
showed a mid-level shortwave trough and jet streak amplifying across
the northern Rockies. Downstream of the trough across western South
Dakota, radar showed a broad area of stratiform precipitation
developing from increasing synoptic lift ahead of the trough. Model
soundings show widespread isentropic ascent with strong low and
mid-level warm advection across much of South Dakota. This strong
lift will support mesoscale banding in the precip shield late this
evening and overnight. Heavy snowfall rates of 1 to 2 inches per
hour will be likely as these bands develop and move northeastward.
Current model guidance suggests the most likely time frame for the
heaviest snowfall rates will be between 6 and 9 UTC across north
central South Dakota. With time, the heavier snow axis should shift
northeastward and weaken as it moves into portions of southeast
North Dakota and perhaps west central Minnesota.

..Lyons/Grams.. 10/22/2020

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...FGF...ABR...BIS...UNR...

LAT...LON   45199812 44969963 44950097 45170170 45460201 45740218
            46020192 46310036 46529857 46419714 46269612 45889618
            45539702 45339748 45199812 

Read more

from SPC Forecast Products http://www.spc.noaa.gov/products/md/md1748.html