Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
411 PM EST Sun Feb 07 2021

Valid 00Z Mon Feb 08 2021 - 00Z Thu Feb 11 2021


...Maine...
Day 1...
System currently impacting the Northeast will continue to move
progressively northeast - tracking east of Cape Cod this evening
and then east of Nova Scotia overnight.  Snow is expected spread
east into eastern Maine this evening, with heavy
accumulations(6-inches or more) likely across Downeast Maine.

...Northern Rockies...
Day 1...
A string of shortwaves embedded within fast, northwest flow, along
with an arctic boundary, will continue to support periods of
mountain snow across the Northwest into the northern Rockies. 
While widespread additional heavy accumulations are not expected,
some areas, especially those in and around the Bitterroot range
could see locally heavy accumulations (8-inches or more) through
the evening and overnight.

...Great Lakes and Ohio Valley to the Northeast...
Day 2...
A fast-moving shortwave is expected to support mainly light snow
accumulations as is moves across the region Monday night and
Tuesday.  While some orographically favored areas across Upstate
New York and western New England may see locally heavier totals,
widespread accumulations of 4-inches or more are not expected.

...Ozarks and Mid Mississippi Valley to the Ohio Valley and
Central Appalachians...
Day 3...
A subtle shortwave moving through the base of a broad upper trough
will support isentropic lift and the development of light
precipitation across the Ozarks and mid Mississippi valley by late
Tuesday.  Then by early Wednesday, right entrance upper jet
forcing along with a low-level boundary is expected to support the
development of better organized precipitation from the mid
Mississippi through the Ohio valleys.  Shallow arctic air in place
will likely support a wintry mix, with the 12Z models showing a
good signal for at least minor ice accumulations from southern
Missouri and northern Arkansas eastward along the main stem of the
Ohio River beginning late Tuesday and continuing into Wednesday. 
More snow than freezing rain is expected farther to the north,
with portions of central Illinois, Indiana, Ohio and central
Appalachians likely to see at least a few inches of snow Tuesday
night and Wednesday.

Pereira