Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
254 PM EST Thu Feb 16 2023

Valid 00Z Fri Feb 17 2023 - 00Z Mon Feb 20 2023

...Upper Midwest, Great Lakes, Northeast...
Days 1-2...

A positively-tilted trough extending from Iowa to the southern
High Plains with the developing surface low over the Midwest
tracking over southern New England out into the Gulf of Maine
Friday afternoon. Heavy snow shifts off the L.P. this evening and
then across northern Maine late tonight through Friday. Day 1 snow
probabilities for 8 or more inches are low near the Thumb of the
L.P. and moderately high across far northern Maine. Along/just
north of the low track is a stripe of mixed precip with decent
width swaths of sleet and freezing rain. A stripe of 1" sleet is
likely along with low Day 1 probabilities for a tenth inch of ice
over western NY, far northern NY and east across VT/NH and
south-central and eastern Maine.

With the strong N/NW flow behind the departing system, the setup
is favorable for at least modest LES south of Lakes Michigan and
Erie, with some upslope snow accumulation possible across the
Appalachians of WV. Day 1 WPC probabilities for more than 4 inches
of snowfall are as high as 40% for the nearshore part of Chicago
and far northwest IN.


...Northern Cascades and Down The Rockies...
Days 1-3...

Low pressure continues to spin off a trough off the West Coast and
will shift south through Sunday. The parent trough currently over
BC shifts over WA into MT tonight with a reinforcing trough
shifting south over BC Saturday, crossing over WY Sunday. Day 1
snow probs for 6 or more inches are moderate for the northern WA
Cascades with snow levels around 2000ft, bringing some impacts to
pass level. Then Days 2.5 snow probs for 6 or more inches are
moderate for the higher ID/MT and western WY ranges, adding in the
Medicine Bow/Park Range along the WY/CO for Day 3.


Jackson


...Key Messages for Feb 14-17 Winter Storm...

--A corridor of mixed precipitation, including sleet and freezing
rain, is expected to produce moderate ice accumulations across
portions of northern New York and New England.  Dangerous travel
conditions, power outages, and tree damage are likely.

--Heavy snow across northern Maine will feature snowfall rates of
1+"/hr at times, along with wind gusts up to 40 mph, will limit
visibilities and create dangerous travel conditions. Tree damage
and isolated power outages are possible. 

--A brief period of very cold air will follow this system.
Sub-zero wind chills are forecast for snow-covered portions of the
Upper Midwest and northern Great Lakes tonight and northern New
York and New England Friday night.