ZCZC SPCSWOMCD ALL
ACUS11 KWNS 130958 
SPC MCD 130958 
SDZ000-NDZ000-NEZ000-MTZ000-WYZ000-131600-

Mesoscale Discussion 1851
NWS Storm Prediction Center Norman OK
0458 AM CDT Wed Oct 13 2021

Areas affected...Portions of eastern WY...the extreme western NE
Panhandle...the far western Dakotas...and southeastern into
east-central MT

Concerning...Heavy snow 

Valid 130958Z - 131600Z

SUMMARY...Moderate to heavy snowfall, with rates around 1-1.5 inches
per hour, should occur this morning. Near-blizzard conditions are
also possible with strong/gusty winds.

DISCUSSION...A mature mid/upper-level cyclone evident on water vapor
satellite imagery will continue to eject northeastward across the
central/northern High Plains this morning. A deformation band on the
back side of the cyclone is beginning to fill in as low/mid-level
frontogenetic forcing increases. Current expectations are that a
mostly north-south oriented band of moderate to heavy snow will
develop over parts of eastern WY/MT into the western Dakotas over
the next few hours this morning, and gradually shift northward with
time. Even though low-level temperatures are marginal (generally
28-33 degrees F), strong cooling aloft associated with the upper low
should support snow as the main precipitation type. Lift through the
saturated dendritic-growth layer and consensus of latest
high-resolution guidance both suggest snowfall rates of 1-1.5 inches
per hours will likely be common, with locally greater rates
possible. Finally, near-blizzard conditions with reduced
visibilities should also occur across this region, as a strong
pressure gradient and gusty winds will exist on the back side of a
surface low that will develop northward from NE into central SD this
morning. Indeed, blizzard conditions have recently been reported at
KDGW in eastern WY.

..Gleason.. 10/13/2021

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

ATTN...WFO...BIS...UNR...CYS...BYZ...GGW...RIW...

LAT...LON   42910372 41880397 41810465 42120527 42820597 44540615
            45750611 46820566 47510489 47660416 47460363 46330348
            45170341 44030337 43740364 42910372 

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