FOUS11 KWBC 270817
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
317 AM EST Fri Feb 27 2026

Valid 12Z Fri Feb 27 2026 - 12Z Mon Mar 02 2026

...Northwest Montana... Day 1...

Continued strong westerly mid and upper level flow across the
Northwest will direct modest moisture into the upslope terrain of
the WA Cascades and northern Rockies today before flow turns more
northwesterly and drier by Saturday. Snow levels are forecast to
remain around 2000-3000ft across the region before dropping below
2000ft across northwest MT on Saturday as a strong cold front dives
southward and increases precipitation late tonight, while
precipitation coverage drops throughout today across the far
northern WA Cascades. WPC probabilities for at least 8" of snow
remain moderate (50-70%) above about 4000ft in the Lewis
Range/Glacier National Park region of northwest MT.

...Northern Plains... Days 1-2...

A cold front will dive out of Canada and sink rapidly southward
Friday, reaching the Central Plains by tonight. As this front
continues south, a modest 700mb trough will dive E/SE along the
front, pushing modest WAA atop the boundary and into the Northern
Plains beginning Friday evening in the High Plains of Montana and
then continuing E/SE through the Upper Midwest by Saturday evening.
This will result in modest 295K isentropic ascent into near-
normal PWs to support expanding precipitation. This precipitation
will likely manifest as a narrow channel with moderate to heavy
snow rates as a dynamic jet structure arcs overhead enhancing the
700-600mb fgen to provide lift directly into the deepening DGZ.
This should create a narrow band of snow translating along its long
axis, leading to a long duration of moderate snowfall rates from
eastern MT through southern WI before weakening as it ejects
eastward Saturday night.

There remains some latitudinal spread in guidance regarding the
location of this band, but CAMs and recent global guidance
highlight a maximum localized corridor of 4-8" is possible. This
WAA fgen scenario usually tends to favor more northern solutions,
but that is highly dependent on the tightening thermal gradient
and overall amplitude should the higher-end scenario occur. Recent
short-term HRRR trends are for a more amplified western U.S. ridge,
which is why the 06z HRRR (and even 06z NAM) trended north and
heavier with its snowfall axis. Given the spread and very narrow
snow band, ensemble probabilistic guidance remains quite low, but
the strong fgen collocated with SLRs around 20:1 support a high-
end snowband potential. WPC probabilities are moderate (50-70%
chance) for at least 2 inches of snow from southwest ND to southern
WI, with locally higher amounts above 4 inches possible (10-30%),
highest across the Dakotas and southern Minnesota. Should guidance
come into better agreement regarding placement of this snowband,
expect these probabilities to increase.

...Central Plains into the Midwest... Day 3...

Broad ridging over the West is progged to become suppressed
somewhat on Sunday as a shortwave emerges from the Pacific and
races quickly over the top of this ridge. As this shortwave moves
into the Central Plains Sunday morning, it will move atop the low-
level baroclinic zone accompanying a surface cold front to produce
a wave of low pressure and accompanying increased ascent. Most of
this lift will be produced via isentropic upglide, especially along
the 290-295K surfaces, with the driving WAA pushing a warm nose
northward atop the cold dome to the north. While there is still
quite a bit of uncertainty into both northward latitudinal advance
of precipitation, as well as timing of the heaviest rates, there is
increasing confidence in a swath of mixed snow/sleet/freezing rain
spreading from the Central Plains into the Midwest late Sunday
into early Monday. Although adjustments in the forecast are likely,
current WPC probabilities indicate a 20-40% chance for at least 2
inches of snow from southern IA and northern MO to central/northern
IL, with light freezing rain possible just to the south of the
heaviest snowfall. Current freezing rain probabilities for
exceeding 0.1" are low (<10%) across northeast KS.

Snell
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