Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
404 AM EDT Wed Apr 13 2022

Valid 12Z Wed Apr 13 2022 - 12Z Sat Apr 16 2022

...Northern Plains/Upper Midwest...
Days 1-3...
...Significant and potentially historic blizzard continues for
portions of the Northern Plains...
Blizzard conditions will persist across portions of North Dakota
and eastern Montana as a deepening closed low drifts east across
the northern Plains today.  In addition to strong and gusty winds,
moderate to heavy snows will focus on the west side of a
developing surface-to-low level wave.  This wave is forecast to
lift north from eastern South Dakota into eastern North Dakota
this morning where it is expected to linger into tonight before
tracking northeast on Thursday.  WPC probabilities indicate that
additional snow accumulations of 8 inches or more are likely
across portions of north-central and northwestern North Dakota. 
On Thursday, generally light wraparound snow is expected to shift
east, with a few inches likely across northern Minnesota.  Snow
will continue to wane and winds subside as the low lifts farther
northeast across Canada and high pressure settles into the
northern Plains Friday into Saturday. 

...Pacific Northwest and Northern California to the Northern
Rockies...
Days 1-3...
An upper low in the southeastern portion of an omega block will
remain in place over the Northwest, maintaining a cold and
unsettled pattern across the region.  A series of shortwaves
moving through the broader scale flow will support periods of
organized precipitation, producing locally heavy amounts including
areas of heavy mountain snow.  Locally heavy accumulations are
expected for the southern Oregon and far northern California
mountain today into Thursday.  With snow levels remaining low,
additional light accumulations can be expected across the Oregon
lowland areas.  Models show a relative break for most areas early
Friday before another shortwave moves into southwestern Oregon and
Northern California by early Saturday.  Southwesterly flow ahead
of the system will increase snow levels on Friday before it moves
inland on Saturday.

For Days 1-3, the probability of 0.10 inch or more of ice is less
than 10 percent.

Pereira


~~~Key Messages for April 13-14 Blizzard~~~

--A blizzard will continue to impact portions the northern Plains
today.

--The combination of heavy snow and strong wind gusts will produce
dangerously low visibility with significant blowing and drifting
of snow.

--Travel will be remain difficult to impossible, and widespread
power outages and tree damage are expected. Significant impacts to
livestock are also possible.

--Snowfall is likely to reach record levels in parts of eastern
Montana and western to central North Dakota, with maximum storm
total snowfall of three feet possible.