885 FXUS63 KGRR 092026 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 326 PM EST Tue Dec 9 2025 .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 /18Z TAFS THROUGH 18Z WEDNESDAY/... Issued at 1259 AM EST Tue Dec 9 2025 MVFR dominates the pattern this afternoon with gust southeasterly winds. Winds have gusted upwards of 33kts. Expect this gusty winds to continue with a lull in the winds between 22Z to 03Z. Snow is still expected to move in from the southwest between 00Z to 03Z tonight with a transition to a rain/snow mix to rain along and south of the I-96 corridor into Wednesday morning. Freezing rain remains possible during the transitions. Snow is expected again early Wednesday morning with a transition from rain to snow. IFR cigs are expected after 00Z with ceilings improving slowly tomorrow. Ceilings will improves from the Northwest to southeast behind the front late tomorrow morning, early afternoon. Vsbys will remain MVFR and lower with periods of IFR vsbys possible with Fog/mist due to the rain/snow transition around 14Z Wednesday. LLWS is expected after 07Z until around 12Z due to the approaching front at GRR, AZO, BTL, LAN and JXN. && .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. && $$ DISCUSSION...Ostuno AVIATION...Ceru MARINE...Ostuno

NWS GRR Office Area Forecast Discussion