Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
339 AM EST Fri Nov 16 2018

Valid 12Z Fri Nov 16 2018 - 12Z Mon Nov 19 2018


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

A Nor'Easter will continue to move along the northeast CONUS coast
today. The TROWAL across the north and west sides will continue to
produce heavy snow until it pushes east of ME before 00Z. A
comparatively thin stripe of wintry mix is expected across
southern New England up along the ME coast where overrunning  is
expected in the warm sector ahead of the low. Freezing rain totals
are forecast to be less than 0.1" though pockets of greater
amounts are possible with plenty of dry/cold air available from
the Canadian Maritimes. Moderate WPC probabilities for 8" are
across northeastern ME.

A secondary upper trough crosses the northeast this afternoon
through this evening resulting in a prolonged snow for the upper
northeast, particularly in the lake effect snow belts.

...North and Central Rockies and Northern Great Plains...
Days 1-2...

A shortwave trough digs the mean western trough across the
Northern Rockies through Saturday, with a powerful 1042mb surface
high building in from the Canadian Prairies. supported by modest
Pacific jet energy, will spread moisture out over the the
north-central CONUS. At the surface a cold front will dive
southward across the Northern Plains and bank against the
mountains producing a sharpening baroclinic gradient and upslope
low-level flow today. Meanwhile, the eastern side of the front
will become parallel to the jet in a swath across ND. These
dynamics and Pacific moisture should lead to a narrow band of
heavy snow, particularly over ND. Moderate WPC probabilities for
8" on Day 1 are across the northern Rockies and ND.

Jackson