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FOUS11 KWBC 281952
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
252 PM EST Sun Dec 28 2025

Valid 00Z Mon Dec 29 2025 - 00Z Thu Jan 01 2026

*** Major Winter Storm for the Upper Midwest/Great Lakes and
 Northeast into Monday ***


...Great Lakes/Northeast...
Days 1-3... Maximum impact level from WSSI: Major to locally=20
Extreme

There are no shortage of weather-related hazards for this impending
major winter storm. Below is a break down of these hazards over the
next 1-2 days.

--Snow and Wind--

The deepening upper-level low over the Midwest this afternoon will
work in tandem with a coupling 250mb jet streak structure to=20
support a rapidly deepening surface low that will track from=20
northern Illinois through lower Michigan tonight. Anomalous PWATs=20
ahead of the upper low will wrap around the northern and western=20
flanks of the storm's 700mb low, causing heavy snow to ensue just=20
north of the best 850-700mb FGEN from northern WI on east through=20
the U.P. of MI. In addition, moderate-to-heavy snow breaks out=20
beneath the TROWAL over most of MN and into WI this afternoon and=20
into tonight. WPC's Snowband Probability Tracker shows 1-2"/hr=20
snowfall rates (locally up to 3"/hr possible) in the FGEN banding=20
over northern WI and the MI U.P. this evening and into early Monday
morning. If heavy snow was not concerning enough, high winds will=20
accompany this storm thanks to this storm deepening into the 970s=20
over the Great Lakes Monday morning and strong high pressure over=20
the northern High Plains causing a very tight pressure gradient.=20
Wind gusts up to 50 mph are likely in parts of the Upper Midwest=20
and Upper Great Lakes this evening with gusts topping 60 mph=20
possible along the northern shores of MI's U.P and western shores=20
of MI's Lower Peninsula. The aforementioned TROWAL pivots over the=20
Great Lakes early Monday morning with bursts of heavy snow possible
as far south as Chicagoland and southern MI with lingering bands=20
of lake-effect snow over western MI and the Michigan U.P..=20

WPC probabilities show high chances (>80%) for snowfall totals=20
>12" from northwest WI throughout most of MI's U.P.. Given the=20
longevity of the snow in the MI U.P. through Monday evening (thanks
to LES bands) WPC probabilities show moderate to high chances=20
(40-70%) for localized totals topping 24" for much of the central
U.P. and even 30% for >30" and just west of Marquette. Farther=20
west, WPC probabilities show moderate- to- high chances (50-70%)=20
for snowfall totals >6" around the Twin Cities metro area on east=20
into western WI. Snowfall totals are forecast to range between 2-4"
along the ND/SD/MN borders and as far south as northern IA, but=20
those totals paired with high wind gusts will likely bring=20
blizzard conditions this afternoon into tonight. Travel will be=20
dangerous to impossible in northern WI and the MI U.P. through=20
Monday. Expect treacherous travel due to whiteout/blizzard=20
conditions in portions of the Midwest this afternoon and through=20
Monday morning due to heavy snow and whipping wind gusts topping 50
mph.

--Hazardous Ice--

A heavy wintry mix begins the storm for the eastern U.P. and MI's=20
Mitten through this evening before transitioning to heavy snow=20
overnight. The boundary layer across much of the Northeast remains=20
cold enough at the onset; via both cold/dry wet-bulb temperatures=20
courtesy of a departing Canadian high to the north, or event=20
lingering snow pack from Friday night's winter storm, to allow for=20
freezing rain to efficiently accumulate on all surfaces starting=20
this afternoon from northern PA and northern NJ on north to the=20
Catskills and Finger Lakes, then into the the Hudson Valley,=20
Adirondacks and on north into northern New England this evening and
into Monday morning. The heaviest icing is most likely to occur in
the Adirondacks, Green, and White Mountains where despite the=20
strengthening WAA aloft, low- level cold will be harder to scour=20
out as sub-freezing temperatures lay trapped in the valleys of=20
these regions.=20

WPC probabilities show high chances (>70%) for ice accumulations=20
>0.25" in these mountain ranges with low chances (10-30%) for=20
localized ice accumulations surpassing 0.5". As much as a tenth of=20
an inch of ice is forecast from northern PA this afternoon through
the Poconos, Catskills, Lower Hudson Valley, the St. Lawrence=20
River Valley, through northern CT and central MA, southern NH, and=20
into much of ME. Roads throughout the interior Northeast will be=20
treacherous with lingering ice likely to impact the Monday morning=20
commute. In areas where ice accumulations top 0.25", wind gusts=20
above 30 mph could cause added stress on trees and power lines,=20
leading to instances of tree damage and power outages for the=20
interior Northeast.=20

--Additional Snowfall Monday night and into mid-week--

As the surface low heads north and east into Quebec Monday=20
afternoon, cyclonic flow and strong CAA in wake of the cold=20
frontal passage will keep LES bands and widespread snow showers in=20
the forecast over the (westerly wind) snow belts downwind of Lakes
Erie and Ontario. Plus, NWrly winds will support upslope snowfall=20
from as far north as the Adirondacks, Tug Hill, and Green mountains
to as far south as the Laurel and Potomac Highlands of southern=20
PA, western MD, and eastern WV into Monday night. It is worth=20
noting there is also evidence on 12Z CAMs, via steep low- level=20
lapse rates along a secondary cold front, that snow squalls could=20
race east across eastern OH, much of PA, and Upstate NY Monday=20
afternoon and evening.=20
This is quickly followed by a clipper system that will traverse=20
the Great Lakes from the northwest on Tuesday/Tuesday night,=20
ushering in a round of light to moderate snow over the Great=20
Lakes. The LES machine picks up again over the MU U.P., the Tip of
MI's Mitten, and downwind of Lakes Erie and Ontario into=20
Wednesday before yet another clipper late Wednesday.


...Southeast New Mexico/Guadalupe Mountains...=20
Day 2... Maximum impact level from WSSI: Moderate

A cold front racing south through the High Plains ushers in strong
low-level CAA amidst ENErly flow tonight. This results in=20
topographic enhancement on the Guadalupe and southern Sacramento=20
Mountains that will play a key role in cooling the boundary layer=20
to support snow into Monday. Meanwhile, there are also sufficient=20
synoptic and mesoscale factors to support heavy snow in the=20
Sacramento and Guadalupe Mountains. Sunday night and into Monday,=20
the region will be positioned beneath the divergent right-entrance=20
region of a 250mb jet streak. Over the Southwest U.S., a positively
tilted 500-200mb trough axis stretches as far south and west as=20
the tropical East Pacific. Guidance is in agreement on a healthy=20
plume of anomalous 700-300mb moisture that leads to PWATs that top=20
0.6", or above the 97.5 climatological percentile per ECMWF=20
guidance. Lastly, the 700mb WAA via SWrly flow over southern NM and
west TX runs into northerly 700mb winds over High Plains that=20
causes a band of 700mb FGEN aloft.=20

HREF guidance is highlighting potentially 1"/hr snowfall rates=20
over the Sacramento and Guadalupe mountains between 09Z and 22Z=20
Monday. Given how warm it has been of late in the Southwest, it=20
will take some hours of moderate-to-heavy snow to cool most=20
surfaces to the point where accumulation can steadily occur. WPC=20
probabilities continue to highlight moderate chances (40-60%) for=20
snowfall totals >4" in these mountain ranges. Localized snowfall=20
totals topping 8" are possible in the highest elevations. To the=20
east, light snow of a couple inches is possible to the TX border=20
where WPC probabilities of at least 2 inches are 20-50%. Notable US
roadways that could witness delays due to measurable snowfall are=20
US-285 between Roswell and Carlsbad, then south and west along=20
US-62/180 that cuts through Guadalupe Mountains N.P..

Mullinax/Jackson



...Winter Storm Key Messages are in effect and linked below...

https://urldefense.com/v3/__https://www.wpc.ncep.noaa.gov/key_messages/Late=
stKeyMessage_1.png__;!!DZ3fjg!9MbOzC_a4h8PlEg3Du-zJYl39W383D_Up6CEN5HWcYE91=
uHIINNvX7liReZmhZKY3mnUrd_ExGkIMLXAceRvVZcd_CY$=20



$$

=3D =3D =3D
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