Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
325 AM EDT Tue May 7 2024

Valid 12Z Tue May 07 2024 - 12Z Fri May 10 2024

...Northern Rockies...
Days 1-2...

An anomalously deep, negatively-tilted, upper low will drift north
and stall over the northern High Plains today as it interacts with
a blocking high to its north. Moderate to heavy precipitation
supported by strong upper forcing and low-to-mid level
frontogenesis will shift west into central and western Montana,
bringing high-elevation heavy snow into the region. Guidance
continues to show that the Glacier National Park region and the
central Montana mountains, including the Little Belt Mountains,
will see some of the greatest impacts today. By early Wednesday,
WPC PWPF indicates that accumulations of 8 inches or more will be
common in these areas, with amounts quickly exceeding a foot in
some locations, especially over the Little Belt Mountains. In
addition to heavy snow, strong winds will be a threat. Even in
areas where lighter snow accumulations are expected to occur, gusty
winds and blowing snow will contribute to disruptive impacts,
including hazardous driving conditions.

The low is forecast to gradually weaken and settle south on
Wednesday. However the threat for areas of moderate to heavy snow
will continue, especially from the Little Belt Mountains south into
the Absaroka and the Big Horn mountains. The Little Belt Mountains
could see several more inches before the snow ends Wednesday
night, pushing storm totals well over 2 feet across the higher
peaks.


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

Pereira