Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
315 AM EDT Wed May 8 2024

Valid 12Z Wed May 08 2024 - 12Z Sat May 11 2024

...Northern to central Rockies...
Days 1-3...

Ongoing heavy snow associated with an anomalously deep low that is
currently centered over the northern Plains is forecast to
continue to impact portions of the northern Rockies today. A
southern shift in the focus for the heaviest snows is expected as
the low begins to slowly drift southeast. While snowfall rates are
forecast to decrease across the northwestern and central Montana
mountains, an increase is expected further to the south today.
Guidance shows a mid-level shortwave moving around the backside of
the parent low, along with right-entrance region upper jet forcing
enhancing ascent ascent over southwestern Montana and western to
central Wyoming. Locally heavy snow accumulations are likely across
areas including the Gallatin, Absaroka, Big Horn, and Wind River
ranges. WPC PWPF shows at least 50 percent probabilities for
accumulations of a foot or more across portions of these areas,
with totals likely to exceed two feet in the higher elevations of
the Absaroka. In addition to the heavy falling snow, windy
conditions and blowing snow will contribute to hazardous conditions
across the region.

As the low weakens, snow is expected to diminish across the
northern Rockies tonight, with only light additional accumulations
on Thursday. A new low is forecast to develop over the central
Rockies-Great Basin as energy digs into the region behind the old
low. Guidance shows moisture and forcing sufficient for light to
moderate snow developing over the Colorado Rockies, with several
inches possible over the San Juan and northern Sangre de Cristo
mountains Thursday into Friday.

The probability of significant icing across the CONUS is less than
10 percent.

Pereira