Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
331 PM EDT Fri Apr 19 2019

Valid 00Z Sat Apr 20 2019 - 00Z Tue Apr 23 2019

...The Mountains of south central to southwest MT south across Wy
and central CO...
Days 2-3...

A shortwave dropping slowly along the WA/OR coast Saturday will
drift onshore California and into the Great Basin on Sunday.
Associated with this feature, an upper jet slowly retreating to
the east will leave the favorable diffluent right entrance region
across the ranges of southwest to south central MT, then extending
across the border into WY. The low level convergence and moisture
convergence ahead of the 700 mb front leads to accumulating snow
in these mountains, with several inches in favored upslope areas
possible where WPC probabilities for 8 inches are high.

On day 3,  the 700 mb front drops south towards CO while the upper
low closes off near the Four Corners. The combination of lift due
to frontal convergence and increasing mid-level divergence in an
area of enhanced moisture focuses a period of heavy snow extending
out of the ranges in western WY across the front range in central
CO. Despite high snow levels, several inches are likely, and WPC
probabilities feature a moderate risk for 8 inches in the Uinta of
UT as well as the along the front range of CO. 

The probability of significant freezing rain is less than 10
percent Days 1-3.

Weiss