Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
258 PM EDT Sat Oct 15 2022

Valid 00Z Sun Oct 16 2022 - 00Z Wed Oct 19 2022

Day 1...

The probability of at least 4 inches of snow is less than 10
percent.

The probability of significant icing is less than 10 percent.

Days 2-3...
...Upper Great Lakes...
The first impactful lake effect snow event of the season appears
likely, with several inches of 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 tomorrow, with a new upper
center moving into the Upper Great Lakes tomorrow night 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 Sunday night
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 8-12 inches or more, especially for areas just east of
Keweenaw Bay. 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 snow to the southeast of Traverse City.


The probability of significant icing is less than 10 percent.


Fracasso/Pereira