Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
350 PM EST Wed Jan 12 2022

Valid 00Z Thu Jan 13 2022 - 00Z Sun Jan 16 2022

...North to Central Great Plains/Upper to Mid Mississippi Valley...
Days 1-3...
An open wave shortwave associated with the remnants of an upper
low moving into the Pacific Northwest on Thursday is expected to
phase with a northern stream trough dropping southeast from
western Canada -- forming an amplified positively-tilted trough
over the central U.S. on Friday.  By early Saturday, models show a
closed low developing over the central Plains before digging
farther south into the southern Plains late in the day. 

Models continue to indicate strong low-to-mid level frontogenesis
and favorable upper forcing ahead of the northern wave supporting
the development of moderate to heavy banded snowfall moving
southeast from eastern North Dakota overnight Thursday, into
eastern South Dakota and southwestern Minnesota by Friday morning.
 Latest HREF guidance shows the potential for snowfall rates of at
least 0.5 inch/hr developing during this period.

Moderate to heavy snow bands are expected to shift farther south
into Iowa on Friday before a comma-head associated with the
developing upper low begins to evolve Friday evening.  Light to
moderate snow is then expected to drop south across the mid
Mississippi Valley into the Ozark region by early Saturday.

With the decrease in model spread and increase in QPF,
probabilities for significant snowfall has increased across
portions of the northern Plains and Upper Midwest.  WPC
probabilistic guidance showed a notable increase in the threat for
accumulations of 4 inches or more -- with high probabilities from
central North Dakota to southwestern Minnesota by late Friday and
across much of Iowa by early Saturday.  Within this area, heavier
totals of 8 inches or more can be expected.

Along the western edge of the heavier snow, a wintry mix,
including freezing rain is expected.  While widespread heavy ice
accumulations are not expected, WPC probabilities indicate that at
least some light accumulations are likely from northwestern North
Dakota to eastern Nebraska and western Iowa.

Pereira 

~~~ Key Messages for Winter Storm Affecting the Northern Plains to
Upper Midwest January 14-15 ~~~

-- A fast-moving winter storm will pass through the northern
Plains and Upper Midwest late Thursday night through Friday night.

-- Several inches of snow are expected with the greatest potential
for 8â€+ across the eastern Dakotas through southwest Minnesota
and much of central Iowa.

-- This snow may lead to hazardous to difficult driving conditions
with snow covered roads along with significantly reduced
visibility due to gusty winds.