Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
221 PM EDT Tue Apr 16 2024

Valid 00Z Wed Apr 17 2024 - 00Z Sat Apr 20 2024


...Northern Rockies...
Day 1...

A vigorous positively-tilted trough digs southeastward across the
northern Rockies tonight into Wednesday. Post-cold frontal upslope
on surface northerly flow and the left-exit region of a 110kt NWly
jet will further add lift across MT, ID, and northern WY. Thus,
expect a period of generally light to moderate snow from Glacier NP
southeast through Yellowstone to the Bighorns. The Big Horn
Mountains are likely to be the recipients of the most snow from
this system, with multiple feet of snow expected. Around
Yellowstone, expect 1-2 feet through Thursday, while elsewhere
amounts should stay under 6 inches. By Wednesday night the trough
will push east, moving these same areas into the left-entrance
region of the jet with the supporting shortwave out over the
northern Plains. This should rapidly weaken any ongoing snow in the
aforementioned areas.

...Rest of the Continental US...

Some minor lake-effect snow off of Lake Superior is possible over
portions of the U.P. of Michigan just beyond the Day 3 time period
Friday night.

The probability of significant icing is less than 10 percent.

Wegman