Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
403 AM EDT Wed Mar 16 2022

Valid 12Z Wed Mar 16 2022 - 12Z Sat Mar 19 2022

...Central Rockies...
Days 1-2...

Upper troughing moving through the Great Basin and Intermountain
West begins to split with the southern stream energy amplifying as
it reaches the Four Corners and southern Rockies late tonight.
This will lead to cyclogenesis over the TX Panhandle with
strong/increasing northeasterly flow against the Front Range of
the Colorado Rockies. Broad large scale forcing for ascent also
provided by a coupled jet streak over the region. The resulting
low-to-mid level frontogenesis will bring moderate to heavy snow
to the foothills and mountains, generally east of the divide. The
00Z guidance trended wetter with an average increase of about
0.25-0.35" in QPF for the mountain areas and this led to a notable
increase of 2-4"+ in snow totals. From the Front Range to the
Sangre de Cristo Mountains and onto the Palmer Divide, WPC
probabilities indicate that accumulations of 6-10 inches are
likely, with a slight to moderate signal for 12"+ in the highest
peaks.  While the highest snow totals will be found west of I-25
urban corridor, some minor (2-4") totals may fall toward the urban
areas of Denver to Colorado Springs.


...Midwest to Great Lakes...
Days 2-3...
Low pressure quickly lifting northeast from the southern Plains
will track toward the Great Lakes Friday into Saturday. This
system taps into a bit more moisture surging northward and a
deformation band of precipitation is expected northwest of the low
track. Colder air will be drawn southward into the region and
soundings show a marginally supportive environment for wet snow to
develop if intensity/rates are high enough to dynamically cool the
lowest levels for a switch from rain to wet snow. The GFS and NAM
are the most aggressive/strongest with the deformation band and
better lift through the DGZ resulting in a heavier swath of
accumulating snow. While the other guidance isn't as bullish, the
trend toward a wetter and potentially cooler scenario is seen in
the other guidance such that at least some minor accumulations
can't be ruled out from eastern Kansas toward southern Wisconsin.
For now, the highest WPC probabilities for any accumulations
greater than 1" are across southern Wisconsin, but this system has
lower confidence and bears watching if cooler/stronger trends
continue in later forecast cycles.

For Days 1-3, the probability for receiving at least 0.1" of
freezing rain is less than 10 percent across the lower 48.

Taylor