Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
350 AM EST Thu Feb 03 2022

Valid 12Z Thu Feb 03 2022 - 12Z Sun Feb 06 2022

...Pacific Northwest and Northern Rockies...
Days 1/2...

Continued onshore flow ahead of a shortwave trough passage over
the WA coast late Friday will allow light to moderate snow that
intensifies with the trough Friday into Friday night mainly over
the WA Cascades, Bitterroots, and around Glacier NP with snow
levels around 3000ft. Day 2 snow probabilities are moderately high
for over 6 inches on the aforementioned ranges and the Cascade
passes.


...Mid-South through the Northeast...
Days 1/2...

An upper trough over the southern Rockies amplifies in place today
as it's reinforced by an impulse currently diving SSE from the Pac
NW which allows maintenance/continued slow southward progression
of a long baroclinic zone extending from TX to Maine and Atlantic
Canada. Leading energy from this trough will allow a surface
reflection to develop as it spreads northeast on the immediate
east side of the Appalachians through Friday. Cold air ducting
under the warmer gulf-moistened air that is lifted north ahead of
the trough axis. This allows a rather broad swath of heavy sleet
and freezing rain to develop from central TX and in particular
over the Mid-South and up the OH River, across PA to southern New
England. Day 1 ice probabilities are moderately high for a quarter
inch over eastern AR/western TN across KY and up the OH River to
Pittsburgh with moderate probabilities then over the rest of
central/northeast PA, southern Interior NY into western MA/CT.

Heavy snow north of this mix line, in the deep cold air, is likely
to have rates below 1" per hour today (per the 00Z HREF mean
snowfall rates) from northeastern OK across south-central MO
(including StL), southern IL, south-central IN, and central OH/far
NW PA. Rates increase over NY tonight as the surface low further
develops and upper dynamics increase. Snowfall rates over 1"/hr
become the norm over the Adirondacks, north-central VT/NH, and
Maine late tonight continuing into far eastern Maine early Friday
where day 1/1.5 snow probabilities for a foot or more are
moderate. A continuous stripe over 6" is likely from southeast MO
through Maine.


...Far northern Minnesota...
Day 3...

Low pressure shifts ESE from the Canadian Prairies Saturday with
banded snow shifting ahead of the low center over far northern MN
through the day. There is potential for heavy snow given the
orientation of the bands in the direction of the system motion. As
of now Day 3 snow potential for areas such as the Boundary Waters
are low for over 6 inches.

Jackson  


~~~ Key Messages for Feb 1-4 Winter Storm ~~

-- An expansive winter storm will shift northeast from Texas to
New England today through Friday, bringing the full variety of
winter weather hazards including heavy snow, sleet, and freezing
rain.

-- Locally heavy snow is expected today over the Mid-Mississippi
Valley and Midwest with increasingly heavy and widespread snow
from Ohio northeast through northern New England tonight into
Friday. Snowfall over a foot is likely from the Adirondacks
through a stripe of northern New England.

-- A corridor of heavy ice accumulation is expected from
south-central Texas, the Mid-South through the Ohio River Valley,
and the interior Northeast. This will result in power outages,
tree damage, and dangerous travel conditions.

-- Locations impacted by snow and/or ice from this storm will
experience prolonged below freezing temperatures into the weekend.