Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
245 AM EST Tue Nov 18 2025

Valid 12Z Tue Nov 18 2025 - 12Z Fri Nov 21 2025

...Southern Minnesota into Central Wisconsin...
Day 1...

Low to mid level frontogenesis and coupled upper jet forcing
accompanying an upper low moving moving through the central Plains
this morning is continuing to support a band of light to moderate
precipitation lifting north from Iowa and Illinois into southern
Minnesota and Wisconsin. General consensus of the models indicate
precipitation will remain mostly rain through the remainder of the
overnight with a changeover to sleet and snow near sunrise across
parts of southern Minnesota and central Wisconsin. WPC
probabilities indicate the greatest potential for accumulating snow
beyond an inch is across central Wisconsin, where snow is expected
to linger the longest before diminishing in the afternoon.

...California through the Southern Rockies...
Days 1-3...

A series of upper lows impacting the West will continue through the
period, with the latest system now dropping south along the
California coast. This low is expected to settle into southern
California by late today and linger near the California-Mexico
border into early Thursday before the next system begins to kick it
east as it follows a path similar to its predecessor along the
California coast.

In addition to locally heavy snow along the southern Sierra Nevada
today, moist easterly flow along with favorable upper forcing is
expected to support heavy totals farther to the east along the
White Mountains as well. WPC probabilities indicate amounts greater
than 8 inches are likely for locations above 8,000 feet over the
next 24 hours. Amounts exceeding 8 inches are also expected for the
southern Nevada ranges north of Las Vegas and over the
southwestern Utah mountains.

Wednesday into early Thursday is expected to be a relatively
quieter period. High elevation snows will continue across the
Southwest into the southern Rockies, but apart from some isolated
heavier totals over southern Utah and the higher elevations of
northern and central Arizona, amounts are expected to be generally
light.

A broader threat for heavy snowfall will develop during the day on
Thursday, especially for the San Juan and Sangre de Cristo
mountains, as the leading low begins to move east. However,
southerly winds will keep snow levels high, with the higher
probabilities for accumulations greater than 6 inches remaining
mostly above 10,000 ft.

Meanwhile, mountain snow will spread south across
California on Thursday into Friday morning, but the progressive
nature of this next system will help limit the threat for
widespread heavy amounts.

Pereira