Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
503 PM EDT Wed Apr 01 2020

Valid 00Z Thu Apr 02 2020 - 00Z Sun Apr 05 2020


...Northern/Central Rockies to the Upper Midwest...

Day 1 (ending 00Z Friday)...
A series of mid-to-upper level shortwaves will continue to move
through the base of a broad trough -- pushing a sharp cold front
farther south and east through the northern Rockies and Plains. 
Models show a well-defined wave moving from the Pacific Northwest
into the northern Rockies overnight.  Favorable upper jet forcing
in addition to enhanced low level convergence and upslope flow is
expected to contribute to locally heavy accumulations across
portions of Wyoming into western South Dakota.  Areas impacted are
expected to include the Wind River Range, Big Horn, Laramie,
Shirley and Medicine Bow Mountains, as well as the Sierra Madre
and Black Hills.  WPC PWPF shows high probabilities for
accumulations of 8-inches or more during the Day 1 period across
these areas.  Meanwhile, a wintry mix will follow the front across
the northern Plains and Upper Midwest on Thursday.  Deeper within
the cold air, a stripe of impactful snow is expected to develop
from central South Dakota into northeastern North Dakota.  A
wintry mix is expected farther south and east, with some models
indicating significant ice accumulations across portions of the
eastern Dakotas into western Minnesota.  WPC PWPF suggests ice
accumulations of 0.1-0.25 inch are likely across portions of the
region.

Day 2 (ending 00Z Saturday)...
Wintry weather is expected to continue across parts of the Plains
and Upper Midwest, with additional snows seeming likely across the
eastern Dakotas into western Minnesota, with accumulating more
likely farther south and east into central and eastern Minnesota,
western Iowa and eastern Nebraska.

Pereira