textproduct: Grand Rapids

KEY MESSAGES

- Clipper Brings Snow/Mix Tonight and Wednesday

- Snow Chances Late Week

- Weekend Arctic Blast

DISCUSSION

Issued at 258 PM EST Tue Dec 9 2025

- Clipper Brings Snow/Mix Tonight and Wednesday

The Winter Weather Advisory for tonight and Wednesday was expanded south to the I-96 corridor to account for a slight southward shift of the track of the surface low and its resulting increase in snow totals and potential for icing of surfaces for several hours in this area.

Current radar and obs upstream show an area of light to moderate snow across Minnesota and Wisconsin along an axis of mid-level frontogenetical forcing. This area is forecast to move into Lower Michigan and intensify this evening, aided by the left exit region of a jet core as a shortwave trough consolidates with a pair of upper lows across SE Canada.

The hi-res models show mesoscale banded precip with the potential for snowfall rates of inch an hour between 10 PM and 3 AM. This should result in 3 to 5 inches of snow across the northern zones by Wednesday afternoon. Snow will mix with rain around 3 AM along I-96 and south, with 2 to 4 inches total across I-96 and lesser amounts south, possibly an inch or two along I-94.

Icing of untreated roads, especially dirt roads, could be a problem tonight into Wednesday morning along the I-96 corridor as air temperatures just above freezing may not be warm enough to overcome the residual cold of pavement and soil after several days of arctic air.

The surface low moves east in the afternoon with a trailing area of mid-lvel f-gen and a weak trowal feature providing enough lift to add another inch of snow before ending. Cyclonic flow and cold advection strengthens in the afternoon with temperatures falling below freezing again. Light lake effect snow showers possible, but limited by inversion heights around 5 kft.

- Snow Chances Late Week

Longwave pattern continues to feature the arctic drape across the northern Rockies to the NE CONUS, with fast moving shortwave troughs minoring out as they zip east-southeast. We will have the chance for light snow on Friday and Saturday as an arctic front and polar jet axis influence weather across the Great Lakes. Wind chill temperatures could approach 10 below zero over the weekend.

- Weekend Arctic Blast

A vast area of arctic air pooling across northwest Canada surges southeast by the weekend, with a lobe of the polar vortex reaching northern Lower Michigan by Sunday. 850 MB temperatures plunge below -20C and should result in high temperatures being confined to the teens on both Saturday and Sunday, with lake effect "diamond dust" as the DGZ is near the surface.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 629 PM EST Tue Dec 9 2025

Light snow is crossing Lake MI early this evening, but the heavier precipitation is still back over Wisconsin. This heavier snow mixed with rain will arrive shortly before midnight and continue through the morning. Expect IFR conditions to develop prior to midnight and continue through noon or so before lifting to MVFR. Additionally strong winds aloft will create LLWS for several hours tonight.

Although not included in the TAFs, it's possible brief periods of freezing rain could occur overnight; confidence wasn't high enough to include in the TAFs.

MARINE

Issued at 258 PM EST Tue Dec 9 2025

No changes to the SCA or Gale Warning. Southwest gales expected tonight into Wednesday. Winds will shift to the northwest Wednesday afternoon with wave heights 7 to 12 feet. Gales subside Wednesday evening with Small Craft Advisory conditions likely through at least Thursday.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Winter Weather Advisory from 10 PM this evening to 4 PM EST Wednesday for MIZ037>040-043>046-050>052-056>059. MARINE...Small Craft Advisory until midnight EST tonight for LMZ844>847. Gale Warning from midnight tonight to 7 PM EST Wednesday for LMZ844>847. Small Craft Advisory until 7 AM EST Wednesday for LMZ848-849. Gale Warning from 7 AM to 7 PM EST Wednesday for LMZ848-849.