FOUS11 KWBC 010656
QPFHSD

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
156 AM EST Sun Mar 1 2026

Valid 12Z Sun Mar 01 2026 - 12Z Wed Mar 04 2026

...Central Plains to the Tennessee Valley...
Days 1-2...

Migrating shortwave ejecting out of the Rockies through the Central
Plains to Ohio Valley will lead to a period of mixed precipitation
from KS/NE, east into the Ohio Valley. Initial wave of precip will
form across the Central Plains with a degradation of the lower
boundary layer over time as a marginal warm-nose protrudes the
layer between 925-700mb leading to a band of snow on the northern
periphery of the SLP center with more of a light sleet/freezing
rain signature along and north of I-70 from Northeast KS through
MO. Freezing rain accretion of 0.01-0.05" will be most common
across this area with WPC probs of >0.01" running between 30-60%
over the aforementioned corridor, but well below 10% for >0.1"
meaning limited chances for more considerable impacts.

Further east into the Ohio Valley, western edge of the strong
surface ridge pressing Arctic air into the region will lead to a
touch better isentropic ascent pattern as the slowly maturing SLP
migrating east will allow for a better 850mb jet nosing up into
the very cold boundary layer present across the OHV with the
southern fringes of freezing to sub-freezing air located along the
KY/TN border. Fairly high probs (40-70%) for at least 0.01" are
located across the northern half of KY with the best chance for
~0.05-0.1" located north of I-64. Snowfall of 1-2" are relatively
low across portions of OH/IN with probs for >1" only between 10-30%
over the central and southern portions of each state.

...Mid-Atlantic to Northeast...
Day 2-3...

There has been very little deviation in the forecasted pattern
expected with the next disturbance to impact the Mid-Atlantic and
Northeastern CONUS. An amplifying mid- level trough ejecting out
of the Great Basin will track steadily eastward Monday night
through Tuesday, leading to a surface low formation that will
track along a wavering warm front/stationary front draped eastward
through the Mid-Atlantic. As this low moves east in conjunction
with its parent trough, downstream height rises will occur through
intensifying WAA, with the resulting overrunning/upglide leading to
an expansion of precipitation from the Mid-Atlantic/Central
Appalachians into the Northeast/New England, especially as PWs
surge to above the 90th climatological percentile according to
NAEFS. With Canadian high pressure quickly retreating to the E/NE
ahead of this system, the warm nose accompanying the WAA will be
unobstructed, and this will likely result in a rapid transition
from snow at precip onset, to a mix of sleet/freezing rain, and
eventually rain, even as far north as southern New England. Before
that transition, some impactful winter weather is likely through
briefly heavy snow (although accumulations should be modest) and
the icy sleet/freezing rain combination which will lead to some
satisfactory ice accumulations in the higher elevations of the
Central Appalachians and neighboring valleys where CAD signatures
remain prevalent through Tuesday morning. WPC probabilities for
snow indicate a low-end risk (20-50%) of at least 2 inches of snow
across the higher elevations of the Adirondak's, Green and White
Mountains of VT/NH. For ice, there is a moderate risk (40-80%
chance) of at least 0.1" from the Central Appalachians into the
Laurel Highlands of PA, with locally as much as 0.25" possible.

...Central Rockies to Pacific Northwest...
Days 2-3...

A potent shortwave ejecting out of the Pacific will translate
eastward into the Great Basin and then Four Corners states by
Tuesday morning. This shortwave trough is forecast to close off
across the Inter-Mountain west between UT/CO, helping to initiate
cyclogenesis in the lee of the Rockies as ascent becomes maximized
in the LFQ of a subtropical jet streak arcing towards the Central
Plains. As this low strengthens, increased moisture funneling
northward from the Gulf will track NW into CO/WY/UT as the
accompanying theta-e ridge rotates cyclonically around the low.
This will create significant snowfall accumulations, generally
above 7000 ft, across the Uintas, Tetons, Wind Rivers, and CO
Rockies, including the Park Range and northern Front Range. In
these areas, WPC probabilities of more than 4 inches of snow reach
50-80%, with locally up to 10 inches possible in isolated locations.

By D3, a second potent trough will enter the Pacific coast with
a solid mid-level moisture advection pattern into the Pacific
Northwest. This will allow for snowfall to occur across the
Northern Cascades with snow levels generally primed between
4000-4500ft AGL leading to mainly heavier snowfall totals above the
passes with the maxima focused >6500ft elevation. This will lead to
WPC probs of more than 60% for >4" focused within the higher
elevations of the Northern Cascades and Olympics.

Weiss/Kleebauer

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