FOUS11 KWBC 300711
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
211 AM EST Tue Dec 30 2025

Valid 12Z Tue Dec 30 2025 - 12Z Fri Jan 02 2026

...Great Lakes, Central Appalachians, Interior Northeast...
Days 1-3... Maximum impact level from WSSI: Moderate to Major

Deep upper troughing will linger over southern Hudson Bay/James
Bay for the next few days, maintaining broad cyclonic flow out of
central Canada and across the Great Lakes. This will result in a
mostly continuous period of lake effect snow downwind of all Great
Lakes but focused especially east of Lakes Erie and Ontario. Two
mid-level shortwaves will zip through the southwest/southern base
of the trough which will act to disrupt the banding and also infuse
a bit more lift and moisture to the region. With lake temperatures
in the 30s to 40s and 850mb temperatures -15 to -20C, sufficient
lift will be generated over the lakes on a general NW to W flow
from the Upper Lakes to Lower Lakes, respectively. This will set up multi-banded snows over Michigan with multi to strong single
banded snows over NW PA, western NY, and between Syracuse and
Watertown. The bands will modulate due to the shortwaves moving
through the region, with the first tonight and the second Wednesday
with perhaps a third weaken one overnight Thursday. The passage of
the second shortwave and associated surface arctic front may also
bring the threat for snow squalls tomorrow afternoon into the
overnight (New Year's Eve) from Michigan to Ohio to Pennsylvania
per the Snow Squall Parameter.

In addition to the lake effect snows, strong upslope ascent into
the central Appalachians will favor at least modest totals over
eastern WV northward through western MD and into the Laurel
Highlands in PA, especially Wednesday into Thursday.

WPC's 72-hour snowfall probabilities show high chances (>70%) for
snowfall totals >18" in NW PA and along the Chautauqua Ridge in
southwestern NY into some of the Buffalo Southtowns. Localized
amounts could exceed 2-3ft. Just east of Lake Ontario, WPC
probabilities show moderate-to-high chances (50-70%) for snowfall
totals >18" in the region between Syracuse, Watertown, and east of
Rochester (centered around Oswego). Over Michigan, totals will
likely be lower, but still appreciable. WPC probabilities for at
least 8 inches of snow are highest (>50%) near/southwest of the
Keweenaw Peninsula, the eastern U.P., and over northwestern Lower
Michigan. Farther south, WPC probabilities for at least 8 inches of
snow are highest over eastern WV northward to the Laurel Highlands
in PA. Light to perhaps modest snow is also possible into the
Green Mountains in VT via upslope flow.

...Sierra Nevada to the Central Rockies... Days 2-3...
Maximum impact level from WSSI: Minor to Moderate

A deep trough in the subtropical Eastern Pacific will lift toward
California and weaken on Wednesday, spreading generally light to
moderate QPF over the region. Snow levels will be high

9000-10,000ft) where more than 8 inches is likely above 10,000ft

through Thursday night. Lighter precipitation will spread
northwestward through Utah to the CO Rockies amid high snow levels (8000-9000ft) and generally near to under 6 inches of snow.

Fracasso

$$
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FOUS11 KWBC 010834
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
334 AM EST Thu Jan 1 2026

Valid 12Z Thu Jan 01 2026 - 12Z Sun Jan 04 2026

...Eastern Maine... Day 1...

Potent upper trough will swing across New England today, with an
embedded vorticity maxima lifting into the Canadian Maritimes
Thursday night. The evolution of this vorticity max combined with
at least the distant LFQ of a southeast diving upper jet will allow
a surface low to deepen as it tracks across Northern New England,
intensifying more rapidly in response to a negative tilt of the
upper trough this evening into Canada. While in general this
system will be progressive, an inverted trough positioned west of
the primary low will rotate across eastern Maine as the low shifts
northward, leading to a longer duration of moderate to heavy
snowfall rates (30-50% chance of 1"/hr). This will result in a
swath of moderate snowfall accumulations for which the WPC
probabilities indicate has a moderate chance (50-70%) of exceeding
6 inches, highest across Downeast Maine.

...Great Lakes... Days 1-3...

An arctic front passing east of the Great Lakes early this morning
will leave impressive CAA in its wake, while cyclonic flow asserts
itself across the region. This cyclonic flow will be secondary
enhanced late Thursday night into Friday as another shortwave
passes through the flow, leading to renewed CAA before shortwave
ridging develops by the end of the forecast period.

While this arctic front will maintain a snow-squall risk through
early this morning into New England and the Mid-Atlantic (for which
Key Messages remain in effect, linked at the bottom of this
discussion) the primary hazard becomes widespread heavy lake effect
snow (LES) in the favored W/NW snow belts. The most intense LES
will likely begin late tonight as 850mb temperatures plummet to as
low as -15C to -20C, across lakes that, while they have cooled,
are mostly ice-free. This will lead to impressive SBCAPE as high
5000-1000 J/kg to support a long duration 1-2+"/hr LES event,
especially downwind of Lakes Erie and Ontario due to upstream
connections. The heaviest accumulations D1 and D2 are expected
across the Chautauqua Ridge and along//just barely south of the
Tug Hill plateau before shifting a little south into D2. WPC
probabilities are high (>90%) for 6+ inches in these areas D1,
continuing east of Lake Ontario D2. Locally 2-4 feet of snow is
possible east of Lake Ontario before LES wanes during D3. Downwind
of the other Great Lakes, WPC probabilities D1 feature a moderate
risk (50-70%) for 6+ inches in the eastern U.P., but this wanes
quickly during D2.

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

A deep trough in the subtropical Eastern Pacific will lift
NNE through the central CA coast early today before crossing the
Sierra Nevada and into the Great Basin by Friday morning. The
primary shortwave within this trough will crest an expanding ridge
(amplifying downstream of a more intense trough over the Pacific)
and drop into CO and the High Plains Friday morning/aftn.,
As the trough moves inland, snow levels on the Sierra Nevada will
fall to around 7500ft this afternoon, bringing heavy snow until
precipitation ends this evening. Farther east, and continuing
downstream of this trough/impulse, snow levels will remain elevated
at 7000-8000 ft, but precipitation falling as snow will spread
across much of the Great Basin and Four Corners at the higher
elevations. WPC probabilities D1 for 6+ inches of snow reach above
70% in the Sierra, and locally as high as 70% in portions of the
Wasatch and CO Rockies. Precipitation will linger through D2 across
the Four Corners terrain, but with generally a waning trend.

Then on D3 a more pronounced surge of precipitation spreads onshore
CA once again as a deep trough amplifies offshore, resulting in
impressively amplified southerly flow. This will push moisture
onshore as IVT exceeds 500 kg/m/s (>80% chance). Once again snow
levels will be elevated within the accompanying WAA, reaching as
high as 8000 ft into the Sierra (although much lower around 6000 ft
across the Shasta/Trinity region). The pronounced moisture will
result in heavy snow again above these levels, and with SLR
expected to be low, it will be an impactful snowfall due to snow
load. WPC probabilities D3 are high (>90%) for more than 6 inches
across these mountains, with locally more than 12 inches possible
(30-50% chance) in the Sierra.

...Columbia Basin and Gorge... Day 1...

Increasing southerly mid-level flow over the Pacific Coast will
spread moisture northward, aided by a weakening shortwave lifting
from CA into the northern Great Basin. As this moisture spreads
into the Pacific Northwest, it will overrun a slowly retreating
ridge of high pressure, manifesting with easterly winds draining
into the Columbia Basin/Gorge to maintain cold surface air. This
setup is favorable for light freezing rain with modest accretions
as reflected by WPC probabilities that reach as high as 70% for 0.1
inches of ice. Although amounts are generally light, impacted
travel is likely tonight into Friday morning due to slippery
roadways.

Weiss

...Winter Storm Key Messages are in effect. Please see current
Key Messages below...

https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_1.png

$$
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FOUS11 KWBC 020753
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
253 AM EST Fri Jan 2 2026

Valid 12Z Fri Jan 02 2026 - 12Z Mon Jan 05 2026

...Great Lakes... Days 1-3...

Ongoing lake effect snow (LES) Will continue in earnest today,
especially across the eastern U.P., and downwind of Lakes Erie and
Ontario. This LES will be driven by persistent CAA across the
lakes, leading to steep lapse rates and inversion depths that climb
towards 800mb, leading to 500-750 J/kg of lake-induced instability.
While the mean low-level flow will be a bit more W than NW, this
will help tap an upstream connection from Superior, across Huron,
and towards Lake Ontario, indicating the heaviest snowfall will
likely be along and south of the Tug Hill Plateau through D1 and
into D2 before winding down in response to brief shortwave ridging.
While periods of heavy snow are also likely in portions of the
northern L.P. and along the Chautauqua ridge, the persistence and
intensity of this snowfall should be less. This is reflected by WPC probabilities for 4+ inches on D1 that area 30-50% in the eastern
U.P. and along the Chautauqua Ridge, but above 90% east of Lake
Ontario, where locally 2+ feet is likely on D1. During D2 the
intensity and coverage of LES wanes, but WPC probabilities for 4+
inches remain above 50% near Oswego, NY.

After a brief respite in response to the aforementioned shortwave
ridging, two separate, but fast moving, shortwaves will crest the
ridge to the west and dive rapidly from Saskatchewan/Alberta across
the Great Lakes. The first of these will race southeast Saturday
aftn/night, and while some enhanced ascent and subtly increased
moisture will result in light synoptic snowfall, additional
accumulations from eastern MN through western NY should be minimal.

A more substantial impulse will then drop southeast in a similar
fashion Sunday night, but this impulse will be accompanied by
greater moisture as it originates from the Pacific and ejects from
the Northern Plains rather than central Canada. This will again be
fast moving, but will have more pronounced synoptic lift in
response to height falls, PVA, LFQ jet diffluence, and more robust
850mb WAA leading to enhanced fgen. At this time, the speed of the
system is expected to limit total snowfall, but briefly heavy snow
rates thanks to idealized ascent into the DGZ could produce a
narrow swath of more than 4 inches as reflected by WPC
probabilities that are as high as 50-70% for 4+ inches from near
Duluth, MN eastward through much of the U.P and the neighboring
portions of WI.

...Western U.S. Mountain Ranges... Days 1-3...

An active period of weather continues across much of the West as
Pacific moisture repeatedly surges onshore in response to
persistent troughing offshore.

For D1, a brief period of ridging will blossom along the Pacific
Coast, but downstream into the Intermountain West a shortwave with
Pacific origin will lift steadily northeast while de-amplifying.
This will result in a stripe of precipitation arcing from the
Northern to the Central Rockies, and falling as snow above
6000-7000 ft. WPC probabilities D1 reach above 70% for 6+ inches
near the Tetons of WY and the Park Range of CO, with more
widespread elevated probabilities for 4+ inches across much of the
rest of the terrain in this region.

Then beginning late D1 and continuing into D3, much more pronounced
moisture begins to pivot onshore the Pacific Coast. This will be in
response to an impressive trough aligned just offshore, from which
a surface low will track northeast towards WA state by Sunday
morning, with a secondary wave tracking towards northern CA Sunday
aftn. While these surface lows will help enhance local ascent, in
general moisture will be pronounced across much of the West due to
increasing southerly flow downstream of the primary trough axis
pushing IVT well onshore with magnitudes above 500 kg/m/s. As is
typical with strong IVT plumes, they will be driven both by Pacific
jet energy and warm advection, resulting in elevated snow levels
climbing to 7000-9000 ft ahead of the first wave, and while they
will rise again with the secondary wave, they will generally be
much lower, 5000-7000 ft on D3, even lower, around 3500 ft, in the
Cascades and interior Northwest.

Any ascent forced through synoptic features or upslope enhancement
will cause rounds of heavy snowfall above these elevations both
Saturday and Sunday. WPC probabilities steadily increase and expand
through the weekend, with widespread high chances (>70%) for 4+
inches reaching from the Olympics, along the entirety of the
Cascades, the Shasta region, the Sierra, and through much of the Northern/Central Rockies and into the Wasatch, by Monday morning.
While the heaviest snowfall is likely in the Sierra where many
locations above 6000 ft could experience 2-5 feet of snow, much of
the higher terrain of the West could receive 1-2 feet before
coverage wanes just beyond D3. This will likely bring considerable
impacts to the higher elevations due to generally low SLR snow,
with difficult travel likely across the Sierra Passes.

...Central Plains... Day 1...

A fast moving clipper rounding the western ridge and dropping
southeast over the Central Plains today will be of subtropical
origin. Although this feature will be progressive and of modest
amplitude as it weakens, it will produce sufficient ascent into a
moistening column to produce a narrow corridor of mixed
precipitation in the vicinity of northeast Nebraska. While total
precipitation will be modest, WPC probabilities indicate a 70-90%
chance of at least 0.01" of freezing rain, with locally up to 0.1"
of ice possible leading to hazardous travel.

Weiss
$$

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FOUS11 KWBC 040819
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
319 AM EST Sun Jan 4 2026

Valid 12Z Sun Jan 04 2026 - 12Z Wed Jan 07 2026

...Northern Plains/Upper Midwest/Great Lakes/Interior Northeast...
Days 1-3...

Some modest lake effect snow (LES) will continue through Sunday
aftn, but primarily within a single band south/southeast of Lake
Ontario with upstream connection to Lakes Huron and Superior.
Additional snowfall across this region should be light as reflected
by WPC probabilities for an additional 2+" of just 10-30%,
although brief 1"/hr rates are possible (10-30% chance).

Thereafter, the mid-level pattern flattens a bit as shortwave
ridging expands from the west, leading to pinched and more
progressive flow across the region. Within this flow, two back-to-
back shortwaves will traverse the region bringing rounds of wintry weather.

The first of these will emerge from the High Plains Sunday morning
and push due east across the Great Lakes in a de-amplifying manner
as it becomes absorbed into the pinched westerlies. Despite the
weakening amplitude, height falls, PVA, and the left-exit region of
a strengthening jet streak will produce deep layer ascent, and
the intensification of this jet streak will likely result in
enhanced omega despite the weakening amplitude of the shortwave. At
the same time, increasing and impressive 925-850mb WAA will spread
northeast ahead of this impulse, aligning with the best left-exit
dynamics and the associated response to produce impressive fgen but
with limited temporal duration. Since this feature will be of
Pacific origin, the accompanying moisture will be impressive as
reflected by NAEFS PWs that are above the 97th percentile, aligned
with the strongest ascent. This suggests that as precipitation
expands from MN through the U.P., and into the northern L.P., a
narrow band of heavy snow will develop which has a 60-80% chance
of producing 1"/hr snowfall rates. The duration of these will,
again, be limited to the progressive nature of the wave, but WPC
probabilities for 4+ inches are above 50% from the Arrowhead of MN
eastward through the northern L.P. of MI, with locally 6-8"
possible (30% chance) in portions of the eastern U.P.

Additionally, south of this axis of heavy snow, a corridor of
modest mixed precipitation, including freezing rain, is likely as
the WAA surges a warm nose to around +3C at 850-800mb. The
refreezing layer is quite deep, so this may manifest more as sleet
than freezing rain, but hazardous travel is Sunday evening from MN
through central WI where WPC probabilities for 0.01" of ice are 50-70%.

This lead wave will continue to track into New England before
exiting to the Atlantic Monday night, but additional snowfall is
expected to be light, generally 1-3", although locally higher in
the Tug Hill Plateau through lake enhancement, as ascent weakens.

The next shortwave follows quickly in the wake of the first, and
emerges from CA Sunday evening before racing to reach the Corn Belt
by Tuesday morning. This impulse will track along the southern
subtropical jet, which is progged to intensify over the Central
Plains, reaching towards 140 kts. The favorable overlap of the LFQ
and height falls downstream of the shortwave will likely lead to
surface low pressure development Monday night near Iowa, with this
low then tracking steadily northeast into Ontario by Tuesday
evening. While there is still some spatial spread in the placement
of this low according to the different ensemble clusters, the
increasing ascent will lead to another round of wintry
precipitation from Minnesota through the Great Lakes (where a mix
of freezing rain and snow is likely), with additional mixed
precipitation spreading into New England by the end of the forecast
period. Total ascent with this secondary wave should be less
intense than the lead wave, and the thermal evolution is quite
complex due to potential secondary low development in the Gulf of
Maine, but at this time WPC probabilities for 2+ inches of snow are
just 10-30% in the higher elevations of Upstate NY and northern New England.

For the freezing rain, WPC probabilities indicate a high risk

70% chance) of at least 0.01" of ice from central MN near the

Twin Cities through much of WI and MI, and into central and
northern New England. The greatest risk for at least 0.1" of ice is
likely in parts of northern WI, northern MI, and the higher
elevations of the Catskills, Adirondacks, and southern Greens.

...Western U.S. Mountain Ranges... Days 1-2...

The active west continues into early next week as an anomalous
trough persists just off the Pacific coast through Tuesday morning
before amplifying into a closed low which then undercuts towards
Baja by the end of the forecast period.

Downstream of this trough, nearly continuous S/SW flow will shed
spokes of vorticity onshore, with the accompanying height falls/PVA
leading to rounds of precipitation across much of the western
CONUS. At the same time, a subtropical jet will amplify and waver
from CA through the Central Plains, providing additionally enhanced
ascent. The combination of persistent SW mid-level flow with the
wavering jet stream will surge periods of elevated IVT onshore,
resulting in PW plumes that occasionally exceed the 90th
climatological percentile. While there may be periods of enhanced
ascent locally across different regions, in general the next 48
hours appear to be synoptically forced with broad large-scale
ascent, locally enhanced through PVA where the vorticity lobes
stream overhead, and through upslope enhancement. The strongest
upslope flow continues to be appear focused over the Sierra where
snowfall will be prolific, but heavy snow is likely through Monday
night across much of the region.

With broad SW flow encompassing the region, the accompanying WAA
will surge snow levels to as high as 6000-8000 ft in the Great
Basin and Rockies D1 (but generally 3000-5000 ft elsewhere), before
steadily falling through D2 as a cold front pushes eastward and the
trough axis finally swings farther east to the coast. By 12Z
Tuesday, snow levels are expected to be generally 1500-2500 ft in
the north, to 5000-6000 ft in the south. 2-day WPC probabilities
(12Z Sunday through 12Z Tuesday) feature a high risk (>70% chance)
for 12+ inches in the Sierra, northern CA ranges, Uintas, Tetons,
Wind Rivers, and portions of the Salmon River/Sawtooth/Bitterroots,
with lesser snowfall expected at the other regional terrain. In
the Sierra, 2-4 feet is possible in the higher elevations.

...Cascades... Day 3..

Mid-level flow across the Northern Pacific will become pinched and
zonal Tuesday, while a weak impulses approaches the coast and may
move onshore overnight into Wednesday morning. This zonal mid-level
flow will be topped by a strengthening Pacific jet streak which
will drop gradually southward such that the overlap of PVA/height
falls will match the greatest LFQ diffluence to provide ample
ascent. This will be aided by upslope enhancement into the terrain
thanks to the westerly flow, producing brief but impressive deep
layer lift into IVT that has a >80% chance of exceeding 250 kg/m/s.
While westerly IVT does not usually result in as impressive of
precipitation as that with a S or SW component, a fully saturated
column with steepening lapse rates will result leading to a period
of heavy snow in the Olympics and Cascades of OR and WA. Snow
levels will be generally 2000-3000 ft during this time, so pass
level impacts leading to hazardous travel are expected. WPC
probabilities for more than 8 inches of snow reach 70+%, with more
than 1 foot possible at the passes (Snoqualmie and Stevens included).

Weiss
$$
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FOUS11 KWBC 050758
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
258 AM EST Mon Jan 5 2026

Valid 12Z Mon Jan 05 2026 - 12Z Thu Jan 08 2026

...Upper Midwest/Great Lakes/Northeast... Days 1-3...

Shortwave currently over Wisconsin will track rapidly eastward
while continuing to de-amplify this morning, likely moving off the
Maine coast by Tuesday morning. The weakening trend of this impulse
driven by the absorption into more pinched westerlies will
gradually weaken ascent such that ongoing heavy snow near the Great
Lakes will transition to primarily light snow from Upstate NY
through central/northern New England. Light accumulations of 1-3"
are expected in this region, with locally as much as 4" possible in
the Tug Hill Plateau due to lake enhancement and southern Greens
thanks to upslope flow. In general, however, the most substantial
impacts from this shortwave will end before the new D1 period begins.

Almost as quickly as this first shortwave exits New England, a
second impulse following quickly in its wake will begin to
organize over the Upper Midwest Tuesday morning. This next impulse
stems from a weak vorticity lobe which ejected from the Pacific
trough late Sunday, crested the western ridge, and begins to deepen
as it moves towards the Great Lakes Tuesday. Unlike the lead
shortwave which weakens with time, this feature is expected to
gradually strengthen and gain amplitude as it moves eastward into
Wednesday. Additionally, this shortwave will be joined by an
impressive jet streak to its south (reaching 160 kts from the
Central Plains to the Ohio Valley) and accompanied by Pacific
moisture (PWs above the 90th climatological percentile according to
NAEFS). The resulting surface low which will develop will
additionally enhance ascent, and a swath of moderate to heavy
precipitation is likely from the western Great Lakes through New England.

Thermally, the environment is marginal for wintry precipitation due
to antecedent ridging aloft and strengthening WAA, so p-type from
WI, across the Great Lakes, and into at least central New England
will likely be a mix of rain, snow, sleet, and freezing rain. The
mixed precip will result in some impacts, but WSSI-P indicates only
minor impacts expected due to the progressive nature and mixed
p-type in this region. Still, WPC probabilities for ice accreting
to at least 0.1" reach 30-50% from near the Twin Cities through
central WI and into lower MI. Locally 0.2" of ice is possible, but
snow amounts are expected to be very light as the guidance has
trended a bit warmer tonight.

During D3, secondary low pressure development in the Gulf of Maine
could make snowfall and impacts a bit more impressive over New
England. While there remains considerable uncertainty into the
timing of this secondary low development, a surge of cold air
wrapping behind (and a developing in-situ CAD) should keep p-type
primarily snow in northern New England and mixed
snow/sleet/freezing rain in the higher elevations of Upstate NY and central/southern New England. This is reflected by an increase in
WPC snowfall probabilities, which, while still modest, are as high
as 10-30% D2 into D3 in the higher terrain of NH and ME. Icing to
the south of the snow may locally reach above 0.1" (30-50% chance
in the Adirondacks, Greens, and Monadnocks).

...California... Day 1...

Amplifying trough off the Pacific Coast will deepen into a closed
low today, with this closed center drifting southeast towards Baja
California by Wednesday morning. Downstream of this evolution,
continued SW mid-level flow and aligned Pacific jet energy will
pump moisture northeast, reflected by high probabilities (>80%
chance) for IVT exceeding 250 kg/m/s surging into CA. Although this
IVT will be pushed onshore via WAA, snow levels will generally
remain around 5000 ft as the WAA is offset by slowly sinking
heights downstream of the trough axis. At the surface, of wave of
low pressure will drop along the CA coast, and while there is
considerable spread in the longitudinal placement of this feature,
sufficient additional ascent into the moistening column will
result in periods of heavy snow above 5000 ft in the Sierra and
northern CA ranges D1, and WPC probabilities are high (>90%) for at
least 6 inches more of snow, with more than 12 inches possible in
the higher terrain, especially around Mt. Shasta.

...Olympics, Cascades, and Northern/Central Rockies... Days 2-3...

Mid-level flow becomes increasingly zonal across the Pacific,
directing energy and moisture into the Pacific Northwest beginning
on Tuesday. Aloft, a jet streak will intensify directly atop the
zonal mid-level flow, providing additional funneling of moisture
onshore before the jet starts to slowly sink southward on
Wednesday. This is reflected by a brief period of elevated IVT

90% chance exceeding 250 kg/m/s but less than 25% chance of 500

kg/m/s) Tuesday into OR/WA. As forcing for ascent increases D2 and
D3 through gradual height falls, left-exit diffluence, and
impressive upslope into the Olympics, Cascades, and Northern
Rockies, heavy snowfall will result in these areas, with snow
levels Tuesday 2000-3000 ft, falling to as low as 1000 ft late
Wednesday (higher but still just around 2500 ft in the Central Rockies).

This cooling column, increasing ascent, and impressive moisture
indicates that heavy snowfall will become increasingly widespread
above these snow levels, especially in the upwind regions of the
Olympics, Cascades, and Northern Rockies. Forecast soundings
suggest steepening lapse rates up to as high as 750mb, which
indicates accumulating snow could occur even lower than these snow
levels, and the NBM 10th% fall to as low as 500 ft in the Pacific
Northwest, so lowland snow is possible late in the forecast period.
However, the most significant accumulations, which are likely to
be impressive, will be above 2000 ft, but will encompass most of
the Cascade and Northern Rockies Passes leading to challenging
travel later this week. WPC probabilities D2 for more than 6 inches
of snow are high (>70%) in the Olympics, Cascades of WA and OR,
the Northern Rockies, and as far south as the NW WY ranges (Tetons,
Wind Rivers), with 1-2 feet likely in the higher elevations of
these ranges. During D3, precip wanes a bit across the
Intermountain West, but persists in heavy fashion across the
Olympics and Cascades where WPC probabilities for 12+ inches remain
above 50%. As noted above, the falling snow levels will result in
dangerous travel across all of the important Cascades Passes this week.

Weiss
$$
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* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 060751
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
251 AM EST Tue Jan 6 2026

Valid 12Z Tue Jan 06 2026 - 12Z Fri Jan 09 2026

...Great Lakes & Northeast... Days 1-2...

Amplifying shortwave will move steadily eastward from the Great
Lakes tonight, passing off the New England coast Wednesday morning.
While the flow in which this impulse will be embedded is generally
zonal, some modest amplification is progged by the consensus, with
the subsequent height falls overlapping modest LFQ diffluence from
a jet streak to the south to enhance deep layer lift, especially in
the Northeast. This will likely result in two waves of surface low
pressure: one moving from MI into Ontario, with secondary
development occurring off the coast of Maine. The speed at which
this second low develops, as well as its latitude, will have a
strong influence on how much cold air can lock in across New
England within the in-situ wedge. While the trends in the guidance
continue to be a slightly farther south and stronger offshore low,
which will enable more cold air to lock in, mixed precip is still
likely to be the dominant p-type outside of the higher terrain and
across northern New England. This system should remain progressive
as well, limiting total impacts and amounts.

For areas that receive mostly snow (the Adirondacks and northern
New England) WPC probabilities for 4+ inches of accumulations are
modest at 10-30%, but locally reach as high as 50% in NH and ME. South
of there, a mix including freezing rain is likely, which could
produce more than 0.1" of ice (30-50% chance) highest in the
Greens, Berkshires, and Worcester Hills.

...Olympics, Cascades, and Northern/Central Rockies... Days 1-3...

A powerful storm system over southern AK will work in tandem with
an unusually strong subtropical ridge north of HI to create a
robust 160kt 250mb jet streak in the northeast Pacific. This
will transport potent IVT eastward within pinched but generally
zonal flow, reflected by GEFS probabilities that exceed 80% for 250
kg/m/s, but are less than 25% for 500 kg/m/s. This increasing
moisture, while not exceptional, will be wrung out efficiently by
PVA within shortwaves traversing the flow, the LFQ of a slowly
sinking but strengthening Pacific jet streak, and persistent, at
times continuous, upslope flow, especially in the Olympics and
Cascades. Snow levels will fall to as low as 2,000ft, although the
heavier and more impactful snow will be observed above 3,000ft.
The heaviest snowfall arrives D1, and following a brief break in
the heavier snowfall rates early Wednesday morning, another
disturbance arrives later in the day with more snow in the Cascades
and Olympics. This time, with a colder air-mass aloft, snow levels
dip to as low as 1,000ft Wednesday afternoon and continuing into
Thursday. Although snow levels remain generally at or above 1,000
ft, steepening lapse rates aloft with continued ascent could result
in locally lower snowfall, reflected by the NBM 10th percentile
snow level falling to around 600 ft. While this should still
prevent significant accumulations in the lowlands, some of the
foothills west of the Cascades could see light snowfall on D2 as well.

With snow nearly continuously falling in these ranges through
Thursday, WPC's 72-hour snowfall probabilities are quite impressive
with high chances (>70%) for snowfall totals >24" above 3,000ft in
the Cascades and Olympics, including passes such as Snoqualmie and
Stevens. At the higher elevations, 4-6 feet of snow is possible.
This snowfall, despite elevated SLRs as the column cools, will
result in dangerous travel across most Cascade Passes, with the
WSSI-P indicating a moderate threat (50-70%) of major impacts
through the Cascades. Motorists should prepare for dangerous travel
and potential pass closures this week.

Farther east into the Northern Rockies and then pivoting down to
the Central Rockies, spokes of energy within the generally zonal
flow will provide sufficient ascent to wring out moisture that
spills across the Cascades. Although snowfall farther east should
be somewhat less impressive than points west, WPC probabilities for
12+ inches during the next 3 days are high (>90%) in the higher
terrain from the Blue Mountains of OR through most of the Northern
Rockies, and down through the Tetons, Wind Rivers, and parts of the
Wasatch. Locally, 2-4 feet is possible in the highest peaks of
these ranges, and pass-level travel will also be significantly
impacted this week.

...Four Corners States... Day 3...

Shortwave digging southeast from the Pacific Northwest will amplify
rapidly as it approaches the Central Rockies, potentially closing
off over the CO/NM High Plains Thursday night. There continues to
be a lot of spread in the mid-level evolution leading to lower than
typical confidence by D3, however, the cluster analysis (from 00Z/5
which is the most recent available) suggests there is potential for
continued deepening due to more pronounced upstream ridging leading
to a deeper trough (supported by more than 60% of the members,
although many of these are from the CMCE which may be somewhat
under-dispersive at this time). However, the trends in the
incoming 00z suite suggest the trough continues to be deeper, which
may result in a more substantial winter weather event.

As the guidance has trended steadily slower and faster with this
feature, suggesting more impressive deep layer ascent, the
resulting downstream jet streak has also intensified and arced
more impressively poleward. As this jet arcs northward, the
overlap of LFQ diffluence with height falls will likely lead to lee
side cyclogenesis Thursday evening, within a column that, while
will feature generally normal to below normal PWs, will saturate in
response to increasing low- level easterly flow around the
strengthening surface low. With steep lapse rates aloft helping to
cool the column, and flow becoming increasingly favorable to
upslope into the terrain, at least light snow is becoming likely
for much of the terrain and into the High Plains of CO/NM,
including the I-25 metro which has experienced a relative dearth of
snowfall so far this season. While adjustments in the forecast are
likely, current WPC snow probabilities indicate a high risk (>70%
chance) for 4+ inches of snow across much of the CO Rockies,
including the Front Range, and portions of the Wasatch, and down to
the White Mountains of AZ. The lower elevations of I-25 and into
the High Plains have a 10-30% chance of 4+ inches, although locally
higher amounts are possible across the Palmer Divide and Raton Mesa.

Weiss
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 070816
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
316 AM EST Wed Jan 7 2026

Valid 12Z Wed Jan 07 2026 - 12Z Sat Jan 10 2026

...Northeast... Day 1...

Amplified but progressive shortwave will track over New England 12Z
Wed - 00Z Thu, exiting quickly to the southeast of Cape Cod
tonight. The two distinct vorticity lobes embedded within this
shortwave will drive the two surface lows (one moving across far
southern Canada while a secondary low develops off the New England
coast), with a wedge in-between the two features supporting cold
air and overrunning precipitation. The primary mechanism for
precipitation development will be the PVA/height falls and
increasing isentropic ascent, especially as the secondary low
development occurs, before the flow shifts to produce NW winds and
CAA. There is still some uncertainty into exactly how strong and at
what speed this transition to CAA will occur, but the models
continue to support slightly more cold air, keeping snow the
primary p-type for northern New York and northern New England, with
a mix including freezing rain as far south as CT/RI, but even here precipitation may end as light snow as the column cools.

Overall ascent is transient and moisture is just slightly
elevated, so total accumulations are expected to be modest. This is
reflected by WPC probabilities for an additional 2+ inches after
12Z Wednesday that are 30-50% in the highest terrain of
northern/central ME, and reach above 50% for 0.01" of ice, focused
across the Worcester Hills and Monadnock Region of NH.

...Pacific Northwest, Great Basin, Northern/Central Rockies... Days 1-3...

Deep trough over the Pacific will shift its axis inland by Friday,
with longwave ridging expanding across the Pacific Coast on
Saturday. As this ridge blossoms, precipitation will finally wane
across the area, but until then an extended period of active
weather with significant snowfall will continue.

The strong jet currently in place will dig slowly southward in
tandem with an embedded mid-level impulse tracking towards the
Great Basin. This impulse will be generally within zonal flow,
although as the trough kinks to become more amplified, mid-level
divergence will also increase. Despite a weakening of the onshore
mid-level flow, the upper jet will maintain its intensity of around
100 kts, at least early D1, before weakening, providing sufficient
IVT to fuel heavy precipitation from the Pacific Northwest into the
northern Great Basin and northern Rockies. Ascent will be aided
both by upslope flow and a fast moving surface cold front. Although
forcing looks generally transient, WPC probabilities D1 into D2 are
high (>70%) for more than 4 inches of snow from the Cascades
through the Northern Rockies and into the Tetons, Wind Rivers, and
Uintas, as well as the Ruby Mountains of NV. During D2, forcing
along the front pushes into UT/AZ where additional snowfall
exceeding 4" is likely (>70%) in the Wasatch and Mogollon Rim.

Behind this cold front, snow levels will crash, potentially falling
to below 1000 ft across the Pacific Northwest, while a second surge
of moisture occurs. This second moisture plume is driven by the
upstream jet streak from the primary trough axis, with the
impressive LFQ diffluence overlapping a secondary vorticity lobe
for ascent. As this rides into the Cascades, additional forcing for
lift created by upslope flow will wring out moisture as additional
heavy snowfall in the Olympics and Cascades, with moisture spilling
into the Northern Rockies as well. Notably, with this second
impulse, lapse rates are exceptionally steep beneath the core of
the mid-level trough, so any heavier rates will likely pull snow
down to around 600ft (NBM 10th% snow level), suggesting even some
light accumulations are possible in the foothills surrounding
Seattle and Portland (although the true lowlands will likely miss
out on any snow this time around). Still, the greatest impacts will
again be across the Cascades and the Passes where WPC probabilities
D2 into D3 are high (>70%) for an additional 4+ inches, with 2-day
total snowfall of 2-3 feet likely in the higher terrain, with even
1-2 feet possible at the passes.

...Four Corners into the High Plains... Days 2-3...

Elongated vorticity lobe will spin southeast from the Pacific
Northwest and amplify into deep longwave trough as it approaches
the Four Corners Thursday night. The intensity of this trough
remains uncertain as it amplifies towards the region around 12Z
Friday, but in general the trends have been for a deeper amplitude
while remaining positively tilted. At the same time, the resultant
jet streak downstream of this trough axis will deepen and pivot
northeast, reaching as high as 140 kts across the Southern Plains,
leaving favorable LFQ diffluence into the High Plains and Four
Corners. Where this jet streak overlaps with the most robust height
falls, lee cyclogenesis will likely result, likely in the northeast
plains of New Mexico as reflected by most ensemble members.

This low will move slowly Friday morning before elongating into
faster flow to the northeast by the end of the forecast period.
Before this occurs, a cold front will dig southward through the
High Plains, with the resulting wind field becoming more E/NE and
upsloping into the terrain of CO and NM. This will provide
additional ascent to the region, which will already be influenced
by favorable synoptic lift, suggesting a period of moderate to
heavy precipitation Thursday night through Friday aftn. Most of
this will fall as snow, especially as the cold front sags south and
cools the column through favorable CAA. However, there is still
uncertainty into how much snow will fall, especially from the
Palmer Divide northward where a significant 850mb moisture gradient
is expected. The ECMWF and its ensemble members are much drier
farther north than the other camps, but locations across southern
CO and northern NM have higher confidence in impactful snowfall,
including along the I-25 urban corridor. While the Palmer Divide
will likely experience significant snowfall due to the higher
elevations and more pronounced upslope, areas north of there,
including Denver, may experience lesser snow. However, in an area
that has seen very little snow so far this winter, this could
still be an impactful event for much of the region, with heavy snow
pulling northeast into OK/KS by the end of the period beneath the
upper jet streak.

Although confidence is modest for this time range, current WPC
probabilities are high D2 for at least 6 inches of snow across the
CO Rockies and into the White Mountains of AZ. Late D2 into D3 as
the surface low consolidates and upslope flow improves, WPC
probabilities indicate a greater risk, (50-70% chance), for at
least 6 inches of snow in the Front Range, Palmer Divide, Raton
Mesa, Sangre de Cristos, and into the high plains of southeast CO.

Weiss
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 080813
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
313 AM EST Thu Jan 8 2026

Valid 12Z Thu Jan 08 2026 - 12Z Sun Jan 11 2026

...Pacific Northwest, Great Basin, Northern Rockies... Days 1-1.5...

A shortwave trough over northern CA this morning will strengthen as
it tracks south and east into the southwestern U.S.. Farther north,
a second shortwave trough over British Columbia will also dig
farther south across the northern Rockies and northeast High
Plains. Residual 700-300mb Pacific moisture will stream across the
Pacific NW and into the both the Northern Rockies and Great Basin
to continue to produce additional mountain snow through Thursday.
Snow levels in the northern Cascades and Olympics will be as low as
1,000ft today, but the heavier snowfall will remain confined to
elevations above 2,000ft. Farther east, the northern Rockies'
heaviest snowfall will be above 5,000ft and above 6,000ft in the
Great Basin. WPC probabilities show high chances (>70%) for
snowfall totals >6" for elevations above 3,000ft in the Cascades
and Olympics. Similar high chance probabilities are present in
parts of the Lewis, Bitterroots, Blue, and Teton Ranges for
additional snowfall >4". Snow will linger longest over the Cascades
and northern Bitterroots through Thursday night, but as the long
awaited upper level ridge builds in on Friday, snow levels will
rise and snow will taper off across all mountains ranges into the
start of the weekend.

...Four Corners into the High Plains... Days 1-2...

A pair of shortwave troughs will be responsible for rounds of
moderate-to-heavy snowfall over the Central and Southern Rockies,
with some snowfall into the central High Plains also expected. This
morning, a strengthening storm system over western KS and eastern
CO brought along a plume of subtropical moisture that is streaming
over the Four Corner states. Snow levels will dip to as low as
5,000ft in central CO and central UT with light snow falling in the
SLC and Denver metro areas. As this disturbance races into the
Midwest this afternoon, a second and more vigorous upper level
shortwave over the Great Basin heads east for the Four Corners
region, bringing with it not only additional Pacific moisture but
height falls, better PVA, and jet streak dynamics aloft. Guidance
shows a healthy area of 700mb Q-vector convergence shifting from
the Mogollon Rim and Wasatch this morning to the central and
southern Rockies by this afternoon, where periods of snow will
envelope most mountain ranges. Snow levels along the Mogollon Rim
will be as low as 6,000ft, while central and southern UT sees snow
levels still hovering as low as 5,000ft. The Gila Mountains and
southwest CO will also see an uptick in snowfall this afternoon
before tapering off early Friday morning.

Farther east, as the enhanced Q-vector convergence heads for the
Front Range of the Rockies and the High Plains this evening, 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. Low-
level easterly winds over the central High Plains fosters upslope
flow into southern CO and northern NM beginning Thursday night and
peaking Friday morning as the 700mb low tracks just south of Raton
Pass. There remains some disagreement on the placement of the best
700mb FGEN as the 700mb low emerges into northeast NM and tracks
towards the OK/TX Panhandles. 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. As the 700mb low
moves northeast Friday afternoon, it will weaken and open up into a
progressive 500mb shortwave, resulting in frontolysis over western
KS that reduces precipitation rates and weakens dynamic cooling aloft.

At this time, WPC probabilities are highlighting the usual
suspects (Palmer Divide, Front Range, Raton Mesa) as having
moderate-to-high chances (>70%) for snowfall totals >4". I-25 at
Raton Pass sports moderate-to-high chances (50-70%) for snowfall
totals >6". Localized snowfall totals >8" along the peaks of the
Sangre De Cristo and Raton Mesa are possible. Farther east, WPC
probabilities show moderate chances (40-60%) for snowfall totals

4" in southeast CO , southwest KS, the far western OK Panhandle,

and the northwest tip of the TX Panhandle. The WSSI shows
widespread Minor Impacts (winter driving conditions; use caution
when driving) for much of the central High Plains with localized
Moderate Impacts possible.

...Upper Midwest & Great Lakes... Days 1-3...

An active stretch of potent storm systems will bring a wide range
of winter precip types to the Midwest and Great Lakes the
remainder of the week. The first storm system will track from KS on
north and east into IA this evening, then over northern MI by
Friday morning. Dynamic cooling beneath a coupling jet-streaks
structure is a plausible scenario from as far south and west as
eastern NE to as far north as the MI U.P.. Given the rapid
progression of the QPF shield, accumulating snow over 1" will be
tough for areas south and west of northern WI. However, over
northern WI and the MI U.P., the timing of the changeover to snow
coincides with the middle of the night, allowing for a better
chance for snowfall accumulations. Marquette's area in particular
will have better chances for accumulating snow as onshore, lake-
enhanced snowfall ensues. Snow tapers off Friday morning as the
storm races north into Ontario. WPC probabilities shows moderate
chances (>50%) for snowfall totals >4" in MI's Huron Mountains with
similar >50% probabilities for >2" extending southward into
northern WI. There is also the potential for light ice
accumulations from northern IA and southern MN to northern WI and
the western MI U.P. with WPC probabilities showing moderate chances
(40-60%) for ice accumulations over one-hundreth of an inch. Ice
accumulation could occur near the evening rush hour in southern MN
and central WI.

By Saturday night, the shortwave trough responsible for the heavy
snow in the the southern and central Rockies/High Plains heads east
towards the MS Valley at the same time as a closed 500mb low over
in Canada plunges south into the Upper Midwest. Guidance has come
into better consensus on the northern stream feature effectively
shearing the southern disturbance and becoming the more dominant
feature. As the 500mb low will direct PVA at the Great Lakes, a
strengthening wave of low pressure and 850-700mb WAA will produce a
larger shield of snow developing initially over southern WI and
northern IL. As moisture wraps northward around the deepening
850mb low over northern MI, a TROWAL will pivot over northern WI
and the MI U.P., prompting the development of heavy snow in these
areas Saturday afternoon and persisting into Saturday night. The
low will occlude over Lake Huron early Sunday morning as the
deformation zone of heavy snow pivots over the tip of MI's Mitten.
Once occluded, the upper low will weaken and move east as more
progressive flow over the Canadian Prairies kicks the storm east
into Ontario Sunday afternoon.

WPC probabilities show moderate-to-high chances (50-0%) for
snowfall totals >4" from the Green Bay area in eastern WI on north
and east through the eastern MI U.P. and the northern tier of MI's
L.P. (Lower Peninsula). The tip of MI's L.P. are favored to contend
with the heaviest snowfall given their longer duration beneath the
TROWAL and some lingering lake-enhanced snowfall in wake of the
storm early Sunday. WPC probabilities depict low-to-moderate
chances (30-50%) for snowfall totals >8" here with localized totals
approaching a foot a possibility.

...Interior Northeast... Day 3...

The storm responsible for heavy snow over the northern Great Lakes
on Saturday will also generate a hazardous wintry mix from
northern PA on northward into the northern Appalachians. The
Northeast will lay ahead of a strong >750kg/m/s IVT that will
direct copious amounts of moisture northward on Saturday. At the
same time, a cold front will provide 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. Precipitation may
start out as snow in far northern New England, where wet-bulb
temperatures down the surface may initially support snow. Still,
the concern is for mountains such as the Catskills, Berkshires,
Greens, Adirondacks, and Whites where surface temperatures have
better odds of staying sub-freezing Saturday night and into Sunday morning.

While minor ice accumulations over one-hundreth of an inch are
likely (>70% probabilities) in the Adirondack and Green Mountains,
these ranges also could witness ice accumulations over one-tenth of
an inch, resulting in greater odds for hazardous travels
conditions Saturday evening that linger into Sunday morning. In
terms of snow, the latest forecast generally calls for minor
accumulations (2-4" of snow) over northern Maine, but localized
totals over 6" are possible. WPC's WSSI-P shows >50% chances for
Minor Impacts over the Adirondacks, the Green and White Mountains,
and through much of northern Maine late Saturday into early Sunday.

Mullinax
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 090819
QPFHSD

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
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 100814
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
314 AM EST Sat Jan 10 2026

Valid 12Z Sat Jan 10 2026 - 12Z Tue Jan 13 2026

...Great Lakes... Days 1-3...

An upper-level low over northern MN this morning will project
healthy PVA over the Great Lakes, as well as strong 700mb Q-vector
convergence over northern MI and MI's Upper Peninsula (U.P.). A
plume of 700-300mb moisture wrapping around the northern flank of
the 700mb low will coincide within a TROWAL that focuses a band of moderate-to-heavy snow over the northern Great Lakes. The storm
system will progress east into southern Ontario by Sunday morning
and snow will begin to taper off by late Sunday morning. Most
guidance shows anywhere from 4-8" of snowfall as far west as the
Porcupine Mountains of MI's western U.P. to the Hurons in the heart
of the U.P. and much of the eastern U.P.. Farther south, the
northern-most locations of Michigan's Mitten are forecast to
receive 4-8" of snowfall as well, with localized totals topping 10"
possible where lake-enhanced snow bands stick around longest. Snow
fall totals of 1-4" are also anticipated along the coast of WI and
the western most counties of MI. The WSSI shows Minor Impacts
across all these regions, suggesting residents are likely to
contend with hazardous travel conditions Saturday night and into
Sunday morning.

In wake of this storm system, two more Canadian clipper systems
will race towards the Great Lakes. The first brings light snowfall
to northern MN Sunday afternoon and then into the northern Great
Lakes Sunday night. It is moisture starved and progressive, so
totals will generally range between a coating-3". As that upper-
level shortwave trough heads for the Northeast on Monday, another
clipper over the Canadian Prairies will track into the Upper
Midwest Monday night. This system has a little more moisture to
work with, but boundary layer temperatures are milder and may
result in more of a snow/rain mix on Tuesday. Both wintry setups
will be closely monitored, but snowfall totals are likely to
produce minor snowfall totals rather than highly impactful amounts
at this time.

...Northeast, Ohio Valley, & Central Appalachians... Days 1-3...

On the eastern flank of the approaching Great Lakes storm system, a
strong IVT topping 750 kg/m/s and an advancing 925-700mb WAA will
provide rich moisture and strong low-level forcing to produce
periods of snow and a wintry mix over the interior Northeast.
Freezing rain will be most common today in northern PA, the
Poconos, Catskills, Adirondacks, Berkshires, and Green Mountains.
Latest WPC probabilities show moderate chancres (40-60%) for ice
accumulations over one-tenth of an inch in the Adirondacks, Greens,
and Berkshires, whereas the rest of the listed areas are generally
expected to witness ice accumulations less than one-tenth. Farther
north, snow will be the more common precipitation type from the
northern Adirondacks and White Mountains through northern Maine.
This is due to their locations farther north of the storm track of
the primary low in Ontario, and their placement north of a
secondary coastal low in the Gulf of Maine. The coastal low will
deepen southwest of Nova Scotia on Sunday and support a
deformation zone of heavy snow over northern Maine through Sunday
night. Snow should finally taper off by Monday morning, although
some blowing snow may still be ongoing across Maine. WPC
probabilities show high chances (>70%) for snowfall totals >6" in
northern Maine with low chances (10-30%) for some localized areas
near Caribou that could receive as much as a foot of snow.

This storm system over the Great Lakes will also be responsible for
other winter related hazards over the Ohio Valley and central
Appalachians. Ahead of an approaching 500mb vort max, a sharp low-
level cold front and healthy PVA aloft will support the development
of snow squalls Saturday afternoon as far west as Iowa that race
east towards northern IL and IN Saturday evening. Snow squalls will
race east through the OH Valley Saturday night and reach the Upper
OH Valley and central Appalachians by early Sunday morning. Light
accumulations of a coating to 1" are possible, but the concern is
rapid reductions in visibilities due to a combination of heavy snow
rates and gusty winds. Surface temperatures will also plummet below
freezing and could support quickly accumulating snowfall on roads.
Motorists should ensure they have a way to receive alerts for snow
squall warnings should they be issued.

Meanwhile, as the aforementioned cold front and snow squalls reach
the central Appalachians Sunday morning, upslope NWrly flow will
foster heavy mountains snow in the Potomac and Laurel Highlands
Sunday and into Sunday night. WPC probabilities show moderate-to-
high chances for snowfall totals >2", but there is a lower chance
scenario (10-30%) where the peaks of the Appalachians in eastern WV
and western MD receive as much as 4-6" of snow. Lastly, westerly
flow off Lakes Erie and Ontario will trigger lake effect snow bands
over the Chautauqua Ridge and over the Tug Hill Plateau Sunday and
into Sunday night. WPC probabilities depict moderate-to-high
chances for snowfall >4" through Sunday night. There will be
another chance for additional light snow over the Adirondacks and
Whites on Monday, but aside from the Tug Hill, snowfall will
generally be between a coating to 2" through early Tuesday morning.

Mullinax
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 110812
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
312 AM EST Sun Jan 11 2026

Valid 12Z Sun Jan 11 2026 - 12Z Wed Jan 14 2026

...Ohio Valley, Central Appalachians, & Mid-Atlantic... Day 1...

Snow squalls are continuing to race east across the Upper OH Valley
this morning that will soon track into the central Appalachians and
northern Mid-Atlantic this afternoon. Snowfall totals will
most likely only resulting in a dusting, although some localized
totals up to 1" are possible. Farther north, snow squalls are also
possible across Upstate NY where the base of a 500mb low and
falling heights will tap into some Great Lakes moisture to trigger
rounds of snow squalls. Despite the minor amounts, rapid
accumulations on all surfaces can occur as temperatures in wake of
the cold frontal passage rapidly fall. Plus, bursts of snow and
gusty winds would lead to dramatic changes from clear visibility to
near whiteout conditions. Residents in these areas should be sure
to monitor any squalls and be on the lookout for any snow squall
warnings as they traverse these regions today. Snow squalls should
taper off by Sunday evening northeast PA and the Lower Hudson Valley.

The heaviest snowfall will occur in the central Appalachians where
NWrly upslope flow generates enhanced snowfall rates in the Laurel
and Potomac Highlands. High pressure over the MS Valley will
quickly build in Sunday evening and snow should taper off by early
Monday morning. WPC probabilities show moderate-to-high chances
(50-80%) for snowfall totals >4" in the >2,000ft peaks of eastern
WV, while western MD and the Laurel Highlands are most likely to
receive anywhere from 1-4" of snowfall. The WSSI shows Minor Impact
potential, suggesting hazardous travel conditions are likely in
affected areas.

...Great Lakes... Days 1 & 3...

Cyclonic flow on the western flank of the departing storm system
over southeast Canada will keep some residual lake-enhanced snow
showers over the Michigan U.P. and Michigan's L.P.. As snow tapers
off over Michigan Sunday afternoon, the heaviest snow will unfold
along the Chautauqua Ridge of PA/NY and down wind of Lake Ontario.
Lake effect snow bands will weaken as the pressure gradient. WPC
probabilities show moderate chances (40-60%) for snowfall totals

4" along the Chautauqua Ridge, while snowfall lingers longest over

the Tug Hill thanks their more favorable position east of a fast
moving 500mb vorticity maximum. WPC 48-hour probabilities (through
Monday night) depict the Tug Hill Plateau with high chances (>70%)
for snowfall totals >8" with some locations likely receiving over a
foot of snow.

Following a brief lull in snow on Monday, focus turns to Tuesday as
an amplifying shortwave trough in south-central Canada dives south
towards the Upper Midwest late Tuesday and into Wednesday. A
deepening clipper over Lake Superior will accompany an Arctic front
that races south over the Michigan U.P. Tuesday night. Strong low-
level CAA looks to reinvigorate the lake effect snow machine over
northern WI, the Michigan U.P., and the tip of Michigan's Mitt.
Latest WPC probabilities show low-to-moderate chances (30-50%) for
snowfall totals over 4" in the Porcupine and Huron Mountains of the
Michigan U.P., with a broader footprint of moderate chance
probabilities (40-70%) for snowfall >2" from northern WI on east
to the the eastern Michigan U.P.. The western Michigan U.P. does
feature the best chances for locally heavier totals, depicted by
low-chance probabilities (10-30%) in the Porcupine and Huron
mountains, as well as the Keweenaw Peninsula. The WSSI-P does show low-to-moderate chances (20-50%) for Minor Impacts over these
aforementioned areas Tuesday night and into Wednesday morning.

...Northern New England... Day 1...

As the primary storm system over southeast Canada weakens and the
coastal low forms over the Gulf of Maine, periods of snow will
continue over northern Maine and the Whites through Sunday. Rates
will lessen this afternoon and evening, but lingering cyclonic flow
on the backside of the coastal storm (located north of Nova Scotia
by Sunday night) will keep snow in the forecast Sunday night. Snow
tapers off by Monday morning, leaving a swath of 6-12" of snowfall
over northern Maine. Farther south, additional ice accumulations
under a tenth of an inch are anticipated over Downeast Maine and
just north of the Maine coast. The WSSI depicts Minor Impacts over
northern Maine, highlighting the likelihood of hazardous travel
conditions. A pair of progressive shortwave troughs will bring some
additional light snow over the Adirondacks, Greens, Whites, and
northern Maine Monday and Tuesday but latest guidance shows
generally a coating-2" for these mountain ranges and northern Maine
through Tuesday night with some localized amounts approaching 4"
possible in the peaks of the Adirondacks.

Mullinax
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 120808
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
308 AM EST Mon Jan 12 2026

Valid 12Z Mon Jan 12 2026 - 12Z Thu Jan 15 2026

...Great Lakes... Days 1-3...

Ongoing westerly flow over Lake Ontario will keep additional heavy
snowfall of 6-12" in the forecast today over the Tug Hill Plateau,
while minor amounts generally between 1-4" occurs around the
Buffalo area and the Adirondacks. By tonight, a Canadian clipper
system will race east over southern Ontario with just enough low-
level WAA and a plume of 700-300mb moisture aloft to support a
brief overrunning setup over the MN Arrowhead, northern WI, and the
western MI U.P.. Ice accumulations are likely to be less than a
tenth of an inch, but WPC probabilities show moderate chances

50%) for ice accumulations over on-ehundreth of an inch. Slick

spots on untreated surfaces are possible Monday night and into
Tuesday morning in affected areas.

As the clipper continues to advance east into southeast Canada, a
robust 500mb vorticity max diving south will accompany a strong
cold front that induces strong CAA over Lake Superior Tuesday
night. Snow will increase in intensity over the Michigan U.P. as
surface-850mb delta Ts dramatically increase and low-level lapse
rates sharpen. The upper-level trough continues to dive south
through the Great Lakes on Wednesday and the same CAA regime will
race south over Lake Michigan. Guidance is coming into better
agreement on the formation of a potent single-band LES setup
producing a swath of heavy snow over northwest IN that could
oscillate at times to as far west as the WI/IL lake shores and as
far east as southwest MI. Meanwhile, much of Michigan's Mitten will
contend with multi-band lake effect streamers as a surface trough
pivots over the Great Lakes Wednesday and into Wednesday night.
This same trough axis, along with the CAA over the Great Lakes,
will trigger lake-enhanced snowfall over northern OH, northwest PA,
and western NY by early Thursday morning. Snowfall will become
more synoptically-enhanced by early Thursday morning as a 700mb low
tracks over Lake Erie and would support heavy snowfall into the
day on Thursday as well.

24-hour WPC probabilities through 12Z Wednesday show
moderate chances (40-60%) for snowfall totals >6" along the
Keweenaw Peninsula and both the Huron and Porcupine Mountains of
the MI U.P.. 24-hour probabilities through 12Z Thursday depict
northwest IN as having moderate chances (40-60%) for snowfall
totals >6". Note that should 1-2"/hr rates materialize, localized
amounts approaching a foot of snow are possible. Lastly, through
12z Thursday, the first 6-12 hours of the impending winter storm
show low chances (10-30%) for snowfall totals >4", but with the
storm likely to produce additional heavy snow along the Chautauqua
Ridge and into western NY, expect heavier snowfall totals to
envelop these areas through Thursday. The WSSI-P currently shows moderate-to-high chances (50-70%) for at least Minor Impacts over
northwest IN, northeast OH, and western NY through Thursday morning.

...Upper Ohio Valley, Central Appalachians, & Northeast... Days 3-3.5...

A robust 500mb shortwave trough over the Upper Midwest will race
southeast toward the Ohio Valley Wednesday night. There remains a
fair amount of uncertainty and model spread that is making this
forecast tough in the Ohio Valley and as far east as the I-95
corridor, but the higher confidence areas are the spine of the
Appalachians. As the 500mb shortwave deepens into a closed upper
low Wednesday night, an accompanying strong cold front will
collide with the central Appalachians with strong 925-700mb layer
CAA. The combination of brisk NWrly flow and excellent PVA aloft
ahead of the upper low will produce heavy snowfall rates from the
Laurel Highlands of southern PA on south to the Blue Ridge and
Smokey Mountains. Snow is likely to continue beyond the scope of
this short-term discussion as cyclonic flow around the western
flank of the storm system sustains favorable upslope flow into the
central Appalachians. The WSSI-P is showing >50% chances for a
at least Minor Impacts over the Smokeys of TN/NC, and both the
windward slopes and peaks of the central Appalachians. Residents
and travelers should plan for a disruptive snow event in central
Appalachians Wednesday evening and into Thursday.

From the Ohio Valley on north through western PA and into the
Northeast the forecast is more murky. Guidance across the board
shows different evolutions and tracks of the aforementioned 500mb
low. The CMC shows a lack of deepening/phasing of 500mb vort
maxima that keeps the synoptic-scale forcing limited. The ECMWF/EC-
AIFS/UKMET camps show a closed low by tracking across the lower
Great Lakes and into the Northeast. To illustrate the ongoing
changes, the 00Z ECMWF from 24 hours ago had a closed low south of
Louisville, KY by 12Z Thursday, while the latest 00Z ECMWF has the
closed low near Cleveland, OH at the same time Thursday. Lastly,
the GFS/GEFS is farther south over the OH Valley that then heads
for the Mid-Atlantic coast as a weakening closed low. All these
evolutions lead to different snowfall footprints, particularly
along the I-95 corridor and northern Mid-Atlantic. No matter the
track of the upper-low, the meteorology involved supports periods
of snow north of the emerging 700mb low. The EPS/GEFS both show the
left-exit region of a strengthening jet streak off the southeast
coast being placed over the Northeast, which also pairs favorably
with 700mb Q-vector convergence on both GFS and ECMWF solutions
over the eastern Great Lakes and interior Northeast. Through 12Z
Thursday, WPC probabilities show northern OH (including the
Cleveland metro) on north and east along the Chautauqua Ridge and
the Adirondacks showing low-to-moderate chances (30-50%) for >4" of snowfall.

Residents and travelers across the Northeast will want to monitor
the forecast closely in the coming days as this complex forecast is
likely to change in the coming days. The lowest confidence in terms
of snowfall amounts and impacts are along the I-95 corridor as
potential scenarios range from a significant winter storm for areas
along I-95 in southern New England to minor snow accumulations at
most depending upon the strength and track of the approaching
upper-low. Not only are amounts unclear, but boundary layer
temperatures at the onset Wednesday night and early Thursday
morning would support rain as the initial precipitation type before
changing over to snow. For now, the spine of the Appalachians are
favored to see accumulating snowfall late Wednesday into Thursday.

Mullinax
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 130808
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
308 AM EST Tue Jan 13 2026

Valid 12Z Tue Jan 13 2026 - 12Z Fri Jan 16 2026

...Great Lakes... Days 1-3...

After a day of light snow across the Upper Great Lakes today thanks
to a Canadian clipper racing east across southern Ontario, a more
potent 500mb shortwave trough with an accompanying arctic cold
front will reinvigorate the lake-effect snow machine starting
tonight. Robust CAA in wake of the arctic front will result
numerous multi-banded streamers, especially over the northern half
of the U.P., northern and western L.P., and south of Lake
Michigan. Additional LES bands are likely over northeast Ohio, the
Chautauqua Ridge, and as far north as the Tug Hill late Wednesday
and through Thursday. The heaviest totals will be found over
northwest IN and far southwest MI where there is high confidence in
a potent single-band of LES that is likely to generate 1-2"/hr
snowfall rates. WPC probabilities show moderate-to-high chances
(50-70%) for snowfall totals >6" in northwest IN with lower chances
(10-30%) for amounts exceeding 8". Given the intense mesoscale
forcing at play, seeing some localized amounts approaching 12"
cannot be ruled out. WPC's WSSI does depict Moderate Impact
potential in the hardest hit areas of northwest IN which could
result in delays and/or closures along I-94 and I-80.

Elsewhere, WPC probabilities show high chances (>70%) for over 4"
of snow across much of the U.P., while western MI (including
Traverse City) show moderate chances (>50%) for over 4 of snowfall.
For Wednesday and through Thursday, moderate-to-high chances
(50-70%) for snowfall >4" are depicted over northeast OH, the
Chautauqua Ridge, and the Tug Hull Plateau. Some areas along the
Chautauqua Ridge and Tug Hill could top 8" and localized amounts
approaching 12" are possible.

...Central Appalachians through the Northeast... Days 2-3...

Over the past 12-24 hours, guidance has continued to trend farther
north with the track of the 500mb low traversing southern Ontario
Thursday AM that then heads into Upstate NY Thursday evening. The
mean 250-500mb mean trough axis is also becoming increasingly more
positive, which is resulting in less deepening of the developing
over Upstate NY by Thursday morning. With these trends, the best
divergence and moisture aloft will reside to the north of the 500mb
low over western and far northern NY. Guidance still disagrees as
to the duration and intensity of the snowfall, but the setup still
favors the development of a TROWAL over the region. Snow will
envelop the Adirondacks and North Country that could reach as far
south as the Finger Lakes. Snow is expected across much of northern
New England Thursday morning, but it is worth noting there is
evidence of a 700-300mb dry slot quickly advancing in from the
southwest that could try to end snowfall sooner over the
Adirondacks, Hudson and Champlain Valleys, and into the Green and
White Mountains. The one area that could still see wrap around
snow is western NY and the Chautauqua Ridge where the pivoting
TROWAL and lake enhanced snow bands are likely to linger through
the remainder of Thursday. Snow is also expected to the north of
the 500mb vort max over northern Maine before tapering off Friday morning.

WPC 24-hour probabilities show the NY's shores along Lake Ontario
and NY's North Country as having moderate chances (40-60%) for
snowfall totals >6" through Thursday night with the Tug Hill
Plateau sporting low chances (10-30%) for localized snowfall totals
approaching a foot. The peaks of the Green and White Mountains are
also likely to see over 6" of snow while northern Maine shows low-
to-moderate chances (30-50%) for snowfall totals >4".

Farther south, guidance has also gradually trended less snowy in
the central and southern Appalachians. Persistent upslope low
amidst cyclonic flow that taps into Great Lakes moisture is likely
to produce anywhere from 1-4" of snow from the Laurel Highlands on
south through the Potomac Highlands and into the Blue Ridge and
Smokey Mountains of TN/NC. The >3,000ft mountain ranges in eastern
WV and the peaks of the Smokeys shows moderate chances (40-60%) for
localized snowfall totals >4" through Thursday afternoon. Snowfall
will taper off by Thursday evening as high pressure over the South
builds in over the region Thursday night.

...Upper Midwest & Northern Plains... Day 3...

On Thursday, another Canadian clipper system ushers in another
round of snow over northern MN, northern WI, and the western U.P..
A plume of moisture associated with a ribbon of 850-700mb FGEN will
produce some minor snowfall accumulations Thursday afternoon. As
the snow via WAA moves into the U.P. Thursday night, another arctic
front will race south through the Northern Plains. The strong CAA
and steepening lapse rates may trigger snow squalls over the
Dakotas and as far west as eastern MT. WPC probabilities
favor northern MN and northwest WI for low-to-moderate chances
(30-50%) for snowfall totals >4", although a coating to 1" due to
passing snow squalls in the Northern Plains are also possible,
along with strong wind gusts that could result in whiteout
conditions locally Thursday night and early Friday morning.

Mullinax
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 140751
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
251 AM EST Wed Jan 14 2026

Valid 12Z Wed Jan 14 2026 - 12Z Sat Jan 17 2026

...Northern Plains through the Northeast, and the Appalachians... Days 1-3...

A longwave trough across the eastern CONUS will amplify and
periodically re-load through the upcoming weekend as repeated
shortwaves intensify and drop southeast from Canada. The core of
this trough will deepen most impressively over the Gulf Coast
Thursday aftn (ECMWF 500mb heights as low as the 0.5 climatological percentile). Within this progressive flow, even as these lead
impulses rotate away on Friday, the next shortwave trough will
follow immediately in its wake, moving from the Northern Plains to
the Mid-Mississippi Valley Friday night. Similar to the Southeast
on Thursday afternoon, 500mb heights over the Missouri River Valley
are likely to be as low as the 0.5 climatological percentile.

The headlining weather hazard, aside from some of the coldest
temperatures and wind chills of the season-to-date, will be the
multiple days of lake effect snow (LES) downwind of the Great
Lakes, especially in the more northerly belts as winds become NNW
beneath strong CAA. WPC probabilities for LES are high (>70%) for
more than 8 inches in the higher elevations of the U.P. including
the Huron and Porcupine Mountains, as well as along the E/SE shore
of Lake Michigan into northern Indiana. Lake-enhanced snowfall
will also unfold along the Chautauqua Ridge and Tug Hill through
Thursday. There are likely to be some localized totals over 12
inches along the Chautauqua Ridge, along the shores of Lake
Ontario, and on the Tug Hill. The heaviest LES is likely in a
single band off Lake Michigan into SW MI/NW IN late Wednesday
through late Thursday. CAMs guidance is showing steep lapse rates
and exceptional vertical velocities that coincide within a fully
saturated DGZ-- a clear sign of a robust LES band. WPC
probabilities show moderate chances (40-60%) for snowfall totals

12 inches where localized amounts approaching 20" cannot be ruled

out given the potential for prolific >2"/hr snowfall rates beneath
a band that will oscillate between southwest MI and northwest IN
for a 12-24 hour stretch.

Across the Central Appalachians and Northeast, the lead shortwave
will not only work together with an Atlantic-offshore jet streak to
create low pressure development across the Northeast, but also drag
an arctic front from the Ohio Valley through the Mid-Atlantic on
Thursday. This will create a short period of heavy upslope snow
from the higher elevations of NC through the Laurel Highlands of PA
where WPC probabilities are moderate (50-70%) for at least 4
inches, generally above 3000 ft, with locally 6-8 inches possible.
The tallest peaks of the Smokey Mountains could see localized
totals approach 12 inches. Farther north into Upstate NY and
northern New England, model guidance has trended snowier over the
past 12-24 hours of model cycles as the slightly longer duration
of moderate-to-heavy snowfall just north and west of the 850mb low
appears to be coming to fruition. The deformation zone will
maintain a saturated profile long enough, within an atmosphere that
supports rising SLRs, to produce heavy snowfall beginning as early
as Wednesday afternoon and continuing into Thursday. WPC
probabilities show moderate-to-high chances (50-70%) for snowfall
totals >8 inches from northwest PA through much of western NY and
into NY's North Country and St. Lawrence Valley.

Finally, on D3 with the next shortwave digging out of Saskatchewan
into the Upper Midwest, height falls and modest warm/moist
advection will create a swath of generally light snow, followed by
strong winds behind yet another arctic front. WPC probabilities
indicate only a 10-30% chance for at least 4 inches of snow for
parts of SD/MN/WI, but WSSI-P suggests an increasing threat for
blowing snow impacts just behind this wave, so travelers should be
prepared for hazardous driving Friday despite the modest snowfall
amounts forecast. Farther east, the shortwave trough will once
again kick-up LES bands across the U.P. and western shores of
Michigan. WPC probabilities show high chances (>70%) for snowfall
totals >4 inches in the U.P.'s Porcupine Mountains and moderate
chances (40-60%) for >4 inches of snow over the western MI shore.
The Porcupines have the best odds at locally heavy totals with
low-to-moderate chances of totals >8 inches.

The probability for significant ice across the CONUS is less than
10%.

Mullinax/Weiss
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 150823
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
323 AM EST Thu Jan 15 2026

Valid 12Z Thu Jan 15 2026 - 12Z Sun Jan 18 2026

...Northeast... Day 1...

Accumulating snowfall will be ongoing this morning across western
and northern NY into northern New England. Additional accumulations
after 12z will be highest across western NY (where some lake
enhancement will occur) and over northern ME...with the probability
of 4"+ of additional snow over 70%. This area of snow will wind
down tonight, although some lingering lake effect snow will
continue along with some wrap around snow into northern ME.

...Central and Northern Plains into the Great Lakes... Days 1-3...

A mid level trough with multiple lobes of embedded vorticity will
drop into the Northern Plains and Great lakes today into Friday
bringing periods of snow. One area of snow will move into MN, WI
and the Great Lakes ahead of and associated with a low moving out
of Canada today into Saturday. Mainly looking at light snowfall
accumulations with this low, although some heavier totals can be
expected off of Lake Superior and Lake Michigan. Overall this is
setting up to be a long duration of light to moderate snowfall
across these lake effect areas, with 72hr probabilities of
exceeding 8" of snow in the 70-90% range across portions of the
western U.P of MI into northeast WI...and 50-70% over western MI.
Lighter amounts, generally in the 1-4" range, can be expected over
MN into WI.

Snow showers will also accompany this system farther west across
the Dakotas into NE, both along the southward dropping cold front
and in its wake. Snowfall amounts are not expected to be
significant, generally on the order of 1-2" or less...however this
snow will be accompanied by significant wind gusts, likely
resulting in reduced visibility and hazardous travel. These snow
showers should start in ND by Thursday evening, spreading south
into SD Thursday night, and then continuing over much of the
Northern Plains through the day Friday. HREF EAS probabilities of
.01" can be a decent proxy for snow shower coverage...and these
values increase into the 70-100% range Thursday night over much of
ND into eastern SD, dropping closer to 40-60% during the day
Friday. Thus anticipating numerous to widespread coverage of snow
showers as the cold front pushes across Thursday night, decreasing
to scattered coverage during the day Friday. Heavier snow shower
coverage may be more isolated to scattered in nature...but where
these brief heavier rates occur a sharp reduction in visibility can
be expected with wind gusts as high as 40-60 MPH. This setup would
seemingly support at least some snow squall potential near and
just behind the cold front as it drops south Thursday night. Snow
shower coverage and intensity should generally be on a downward
trend Friday, however wind gusts will remain high. One limiting
factor for blowing snow impacts from this system is the lack of
antecedent snow cover...however if we are able to get snowfall
accumulations ~2" Thursday night into early Friday then blowing
snow concerns could increase during the day Friday, especially
within snow showers.

...Ohio Valley, Southeast, Mid-Atlantic and Northeast... Days 2-3

A decent amount of uncertainty exists Friday night into Sunday from
the OH Valley into the East Coast...all related to how the multiple
vort maxes interact within the large scale trough moving towards
the East Coast. Model guidance is trending a bit stronger with one
lobe of vorticity Friday night into Saturday moving from the OH
valley into the Mid-Atlantic. This should support an expanding area
of light to moderate precipitation across TN/KY Friday night,
spreading into the Mid-Atlantic and Northeast on Saturday. Not
anticipating any significant snowfall from this feature, but some
light snow accumulations are possible over portions of northeast TN
into KY Friday night. Temperatures are marginal, but enough of the
guidance is just cold enough to support the potential for 1-2" of snowfall...and the latest WPC probabilities of 1"+ are in the
30-60% range, which seem reasonable. Some light snow (generally
under 1") could then spread into portions of the northern Mid-
Atlantic saturday morning, with totals upwards of 1-3" possible
across the interior Northeast.

Attention will then turn to energy diving into the base of the
large scale trough and how this evolves from the Gulf Coast to the
East Coast. Seemingly have 3 deterministic model camps with this
system. The 00z GFS is the slowest and most aggressive with this
feature, taking it neutral to negatively tilted by 12z Sunday
resulting in a more expansive swath of precipitation over the
Southeast Saturday night into Sunday morning. While boundary layer
temperatures are marginal, some accumulating snowfall would be
possible over the Southeast states in this scenario. On the other
hand the ECMWF, while slower like the GFS, is more positively
tilted, keeping the system more suppressed, and thus little to no
winter precip through 12z Sunday. The 00z AIGFS/AIFS/GEM all depict
a quicker shortwave trough that results in a precipitation axis
farther east than the GFS, but moving quicker up the East Coast as
well. This scenario is a warmer one however, with the bulk of the
precipitation staying ahead of the colder airmass. Thus most of the
precip over the Southeast in this scenario is rain through 12z
Sunday. Not really seeing any clear trend to support hedging one
way or another with the forecast at this point, so will just need
to continue to monitor and hope for a more consistent trend today.
Current probabilities of 1"+ of snow through 12z Sunday are low,
only peaking around 5-10% over portions of AL and GA. Probabilities
do increase into the 20-30% range from NC into New England later
Sunday, but the aforementioned model spread will play a significant
role in how that forecast plays out.

Chenard
$$
--- SBBSecho 3.28-Linux
* Origin: Capitol City Online (618:250/1)

FOUS11 KWBC 190842
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
342 AM EST Mon Jan 19 2026

Valid 12Z Mon Jan 19 2026 - 12Z Thu Jan 22 2026

...Great Lakes/Upper Midwest... Days 1-3...

Shortwave trough passages around a deep low over anchored over
Hudson Bay maintain cyclonic flow and Lake Effect Snow across the
Great Lakes snow belts at least into this weekend. The Great Lakes
are ice free away from the narrower bays. 850mb temperatures of
-20C to -25C over surface water temperatures between +2 to 6C will
continue to make for a high delta T and convective development.

A reinforcing trough currently over the U.P. swings east across
the rest of the Lakes today with a leading arctic cold front.
Post- FROPA NW flow through early Tuesday will promote multi-
banded snow into the U.P. and northern Lower Michigan where Day 1
WPC probabilities for >6" are 40-70%.

For Lakes Erie/Ontario, SWly flow veers Wly today with ongoing
single-band LES shifting south of Buffalo and onto the Tug Hill
Plateau. Day 1 PWPF for >6" are 60-80% in these zones. LES
continues through Tuesday night, so Day 2 PWPF for >6" are
especially highlighted over the Tug Hill with values over 80%.

A brief lull occurs Tuesday evening in the western Lakes under
brief ridging until the next shortwave/a clipper system shifts east
through the region Tuesday night through Wednesday. A surface low
lifts from Iowa across the L.P. through that time with synoptic
snow bands across northern Iowa and southern Wisconsin where Day
2.5 snow probs for >4" have risen to 20%. Brief LES can be expected
Wednesday into Wednesday night where Day 3 PWPF for >4" are 40-70%
in the western U.P., the length of the western L.P. shore, and east
of Lakes Erie and Ontario.

Yet another clipper is quick on the heels on a similar path to the
previous with snow bands likely over northern Iowa, southern
Wisconsin and souther Michigan again Wednesday night.

...Central High Plains... Day 1...

Right entrance jet dynamics continue to provide lift over a
baroclinic zone on the central High Plains as high pressure builds
south over the Northern Plains. A decent swath of snow with narrow
embedded bands of moderate to locally heavy snow have developed
from northern CO Front Range to western KS. These will persist into
or through the morning as should slowly sag south to southwestern
KS as the jet also shifts south with the shortwave trough pushing
down the Rockies. An additional few inches can be expected in the
better bands.

The probability of significant icing is less than 10 percent.

Jackson

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FOUS11 KWBC 270733
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
233 AM EST Tue Jan 27 2026

Valid 12Z Tue Jan 27 2026 - 12Z Fri Jan 30 2026

...Great Lakes... Days 1-3...

Broad cyclonic flow and trough passages persist across the Great
Lakes as low pressure over Hudson Bay shifts south over Ontario
through Thursday. These will produce rounds of lake effect snow
(LES) beginning today behind a notable upper trough passage. 850mb
temperatures will remain quite cold during this period, with
temperatures around -18 to -24C, and below the 10th climatological
percentile. According to GLERL, Lake Erie is essentially ice
covered, so available moisture will be limited there while Lakes
Superior and Ontario remain largely open. Westerly flow will
continue across the Lower Great Lakes through Thursday night, with
northerly flow more likely on Day 3 across the Upper Great Lakes,
This allows Days 1-3 PWPF for >8" over 50% in the Tug Hill and for
the eastern U.P. of Michigan. The heaviest snowfall is no doubt
most likely downwind of Lake Ontario and the Tug Hill, where 50-60% probabilities for >18" reach the shoreline of Oswego county.

...Cascades... Days 2/3...

The next trough axis to near the Pacific Northwest shunts the
powerful western ridge eastward Tuesday night, with precip over
the WA Cascades then through Thursday. Snow levels rise from 4000
to 5000ft over the WA Cascades Wednesday through Thursday. PWPF for

6" is 40-70% above the snow level (above pass level) by Thursday.

The probability for significant icing is less than 10 percent.

Snell

...Extreme Cold Key Messages are in effect. Please see current Key
Messages below...

https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_1.png

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