Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
327 PM EST Wed Nov 06 2019

Valid 00Z Thu Nov 07 2019 - 00Z Sun Nov 10 2019


Days 1-2...

...Northeast...
A shortwave trough centered over Ontario on Wednesday will
continue to move east, producing light snow across portions of
Upstate New York and northern New England Wednesday night into
Thursday.  Meanwhile, upstream energy diving into the base of the
longwave trough is expected to re-amplify the flow over the Great
Lakes on Thursday - supporting additional snows from the Ohio
valley into the Northeast.  Models show the trough continuing to
amplify and assume a negative tilt as it moves across the
Northeast on Friday.  Surface low pressure developing along the
Northeast coast Friday morning is forecast to move quickly to the
northeast and strengthen over Atlantic Canada.  Models continue to
converge on a faster and less amplified system, with lighter
accumulations than those shown by yesterday's runs.  However,
there remains some threat for locally heavier amounts - especially
across the Adirondacks and mountains of northern New England. 
Across the Adirondacks, northern Greens and Whites, probabilities
remain high for two-day totals exceeding 6-inches.

...Great Lakes...
Strong cold-air advection and veering winds behind the system
moving into the Northeast will support re-developing snow showers
Wednesday night into Thursday, with locally heavy accumulations
possible along the northwest snow belts of the U.P. and northern
Lower Michigan.  By late Thursday, models show an increasing
signal for single-band heavy snows extending from Lake Huron
across Lake Erie into western Pennsylvania.   

The probability of significant icing (0.25 inch) is less than 10
percent.

Day 3...

The probability of significant icing (0.25 inch) and/or snow is
less than 10 percent.

Pereira