Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
319 AM EDT Sun Oct 16 2022

Valid 12Z Sun Oct 16 2022 - 12Z Wed Oct 19 2022


Days 1-3...
...Upper Great Lakes...
The first impactful lake effect snow event of the season appears
likely, with several inches of heavy wet snow possible across
portions of the U.P. of Michigan. Strong upper ridging into the
Pacific Northwest will maintain a reloading trough into the Great
Lakes into early next week. Another shortwave is forecast to dive
quickly south across central Canada today, with a new upper center
moving into the Upper Great Lakes tonight into early Monday. The
GFS continues to show heights -2 to -3 sigma as a deep upper low
develops over Lake Superior and drifts slowly east across the
region on Monday and Tuesday. Deep northerly to northwesterly flow
west of the low will support 850 temps dropping to around -10C
across western Lake Superior beginning tonight and continuing into
Monday. Ample instability atop lake temperatures +8 to 10C along
with deepening moisture will help support the development of
locally heavy snows, especially along the higher terrain of the
western to central U.P. into far northern Wisconsin Sunday night
into Monday, with the threat for accumulating snow gradually
spreading farther east Monday into Tuesday.  For the two-day
period ending Tuesday, WPC PWPF indicates that accumulations of 4
inches or more are likely across the western to central U.P., with
a significant threat for localized amounts of 12 inches or more,
especially across the higher terrain of north-central Upper
Michigan. With colder air gradually working into Lower Michigan,
rain will mix with and change to snow over some interior and
elevated locations on Monday. There is a low chance (10-40%) of at
least 4 inches of across interior portions of northern Lower
Michigan from near Gaylord to south of Traverse City.

The probability of significant icing is less than 10 percent.

Pereira/Fracasso