Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
357 PM EDT Mon Oct 14 2019

Valid 00Z Tue Oct 15 2019 - 00Z Fri Oct 18 2019

...Northern Wisconsin and the UP...
Day 1 into 2...
A shortwave trough digs southeast into the Upper Midwest through
Tuesday with surface low development as it tracks from WI to lower
MI late Tuesday. A trowal across northern WI and the UP of MI
should be dynamic enough to bring a band of snow to the higher
elevations of this area as it passes late Tuesday. There are low
probabilities for this band to exceed an inch of snow.


...Pacific Northwest...
Days 2-3...
An anomalous plume of moisture is directed into the Pac NW late
Tuesday with an upper trough pushing inland Wednesday night (and
followed by at least two more troughs through the weekend). The
subtropically sourced moisture will have a high snow level, above
8000ft limiting heavy snow to the highest Cascade peaks into
Wednesday. Temperatures aloft fall with the approach of the upper
trough with snow elevations decreasing to around 5000ft under the
trough over WA and northern ID/MT Thursday. Nearly continuous
heavy snow is expected late Wednesday into the weekend for the
high Cascade peaks with the initial wave reaching the northern
Rockies of MT Thursday with higher elevation moderate snow.


...Northeast...
Day 3...
A powerful surface low is expected to develop along the
Mid-Atlantic coast Wednesday as shortwave energy rounds a low
shifting east from the Great Lakes. This pushes the associated
trough into a negative tilt with rapid cyclogenesis expected as it
moves north over coastal New England through Thursday. As it is
rather early in the season, cold air is delayed until Thursday
with sub-zero 850mb temps over interior New England and the
Adirondacks where the snow level reaches 4000ft by late Thursday
per the NBM. Will need to monitor this system for track and
intensity, though it currently looks to not produce much snow
outside of the highest New England and Adirondack peaks.



The probability of significant icing is less than 10 percent Days
1-3.
The probability of heavy snow is less than 10 percent Days 1-2.

Jackson