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Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
319 AM EST Fri Jan 9 2026

Valid 12Z Fri Jan 09 2026 - 12Z Mon Jan 12 2026


...Upper Midwest & Upper Great Lakes...
Day 1...

A swath of heavy/wet snow is ongoing along the western flank of a
storm system racing northeast through the Great Lakes. Snow bands
co-located beneath a classic 250mb jet coupling setup is
maximizing divergence atop the atmosphere at the same time
850-700mb FGEN support intense vertical velocities into a well
saturated DGZ. Boundary layer temperatures are marginally cold,
relaying heavily on the robust vertical velocities aloft and heavy
snowfall rates to keep the depth of the atmospheric column below
freezing. WPC's HREF Snowband Probability Tracker show the
potential for 1"/hr snowfall rates early this morning over
northern WI and the central MI U.P. that includes the Huron
Mountains. The latest forecast calls for 1-3" of snow over north-
central WI and into the heart of MI's U.P.. The Huron Mountains
have the best chances to see 4-6" of snowfall with localized totals
over 6" possible. WPC's WSSI shows largely Minor Impacts in these
areas, although localized Moderate Impacts (hazardous travel
conditions) are forecast around Marquette this morning. Snow tapers
off by midday as the storm races into southeast Canada.


...Central/Southern Rockies & Adjacent High Plains...
Day 1...

A vigorous upper level trough over the Four Corners region will
close off into a 500mb low this morning. This system will escort a
plume of Pacific moisture into the Rockies and central High
Plains. Subsequent PVA aloft and favorable jet streak dynamics will
work in tandem with easterly upsloping low-level winds to produce
heavy snow from the Palmer Divide and Sangre De Cristo to the Raton
Mesa and High Plains.

A closed 700mb low will develop over northern NM that gives rise
to a surface low forming in lee of the Sangre De Cristo mountains.
Snow levels will quickly fall below 5000ft by Friday morning, then
as the FGEN banding ensues over southwest KS, the OK Panhandle, and
the northern most counties of the TX Panhandle, snow levels will
fall to as low as 2,000ft during the day. Low-level easterly winds
over the central High Plains favors upslope flow into southern CO
and northern NM peaking early this morning as the 700mb low tracks
just south of Raton Pass. Where the best FGEN forcing sets up and
the strength of the 700mb low will be vital in where the heaviest
snowfall occurs and how far east away from the Raton Mesa and Front
Range the band of heavy snow can advance. Beneath the 700mb FGEN,
>1"/hr snowfall rates are expected. The latest HREF and WPC
Snowband Probability Tracker depicts this well with 1"/hr snowfall
rates possible anywhere between the Sangre De Cristo and Raton Mesa
to the TX/OK Panhandles and southwest KS. As the 700mb low moves
northeast Friday afternoon, it will weaken and open up into a
progressive 500mb shortwave, resulting in frontolysis over the High
Plains that diminishes precipitation rates and weakens dynamic
cooling aloft.

Recent 12-24 hour trends have been snowier in the High Plains as
far east as southwest KS thanks to the 700mb low remaining in tact
longer as it tracks east. The latest snowfall forecast calls for
anywhere from 6-12" of snow from the Front Range as far north as
Pikes Peak on south along the Sangre De Cristo and into Raton Mesa.
Given the recent trends for heavier snowfall protruding as far east
as southwest KS, snowfall totals of 4-8" (localized totals >8")
are likely in southeast CO, southwest KS, the OK Panhandle, and the
far northwest reaches of the TX Panhandle. The WSSI is showing a
larger swath of Moderate Impacts in these aforementioned areas
with localized Major Impacts highlighted along the Raton Mesa and
very close to I-25's Raton Pass.


...Great Lakes into the Northeast...
Days 2-3...

The shortwave trough responsible for the heavy snow in the the
southern and central Rockies/High Plains tracks eastward into the
MS Valley Saturday night. Farther north, a closed 500mb low in
southern Canada plunges into the Upper Midwest and Great Lakes. As
low pressure deepens over Lake Huron Saturday night, a deformation
zone of snow will envelope the northern Great Lakes. The focus for
heavy snow will be beneath the developing TROWAL that looks to
setup over the U.P. of Michigan. Over the past 24 hours, guidance
has trended more progressive with the storm system and its
associated TROWAL, which has continued the trend of gradually
decreasing snowfall totals. Latest WPC probabilities still show
moderate to high chances (50-75%) for snowfall amounts >4" in the
Porcupine and Huron Mountains of Michigan's U.P., as well as the
norther tier of Michigan's L.P.. Most odds for >6" of snowfall
remain in the 30-50% range, but the Huron Mountains and the tip of
Michigan's Mitten would be most favored for localized snowfall
totals over 8" given additional lake-enhanced snowfall there.

The same storm responsible for the snow over the northern Great
Lakes Saturday night into Sunday will also produce a hazardous
wintry mix across the interior Northeast and heavy snow in northern
New England. A strong >750kg/m/s IVT will direct copious amounts
of moisture northward Saturday into Saturday night. At the same
time, a cold front will inject just enough cold/dry air at the
surface with Canadian high pressure to the north creating a weak
CAD signature over the Northeast. This healthy 850-700mb WAA will
support a classic overrunning setup of >0C air aloft causing a
mixture of sleet/freezing rain to unfold beginning Saturday
afternoon and continuing into Saturday night/early Sunday morning.
Guidance has trended weaker with the primary low over southeast
Canada Saturday night, and with a developing secondary coastal low
near southern New England, the expectation is for sub-freezing
surface temperatures to persist longer. One potential issue for
snow in northern New England is the potential for a 700-300mb dry
slot that could sap moisture in the DGZ aloft over northern NY and
northern VT/NH.

Still, whether it is ice or snow, many of the interior mountain
ranges such as the Catskills, Berkshires, Greens, Adirondacks, and
Whites are favored to see the heaviest wintry precipitation Saturday
night and into Sunday. As the coastal low takes over on Sunday,
lake-effect snow showers are likely to continue down wind of Lakes
Erie and Ontario while northern Maine would be more likely to see
periods of heavy snow. WPC probabilities indicate moderate chances
(40-70%) for minor ice accumulations over one- hundreth of an inch
across the Berkshires, Greens, Adirondacks, and Whites, with low
chances (10-30%) for ice greater than a tenth of an inch in the
Adirondacks. Regarding snowfall, WPC probabilities for >4" are
moderate (40-70%) over the White Mountains and northern Maine.
Northern Maine has the best chances for witnessing locally heavy
snowfall with low chance probabilities (10-30%) for snowfall totals
>8". With lake enhanced snowfall possible in wake of a cold
frontal passage on Sunday, the Tug Hill and Chautauqua Ridge are
sporting moderate-to-high chances (50-80%) for localized snowfall
totals >4" through Sunday night.


Mullinax



$$

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