textproduct: Grand Rapids

KEY MESSAGES

- Rain changing to snow showers tonight, windy

- Up/down temps through weekend, then warmer

DISCUSSION

Issued at 300 PM EST Thu Dec 18 2025

- Rain changing to snow showers tonight, windy

Based on updated snow accumulations and expected wind, we included all of the lake shore counties plus Kalamazoo county in the winter weather advisory.

Regional radar shows a band of rain including a narrow cold frontal rain band moving across eastern Wisconsin and Illinois. This rain will move over the cwa this evening just ahead of the cold front. H8 temps near +8c will quickly fall to -14c by 06z. We expect lake effect snow to develop around 03z and continue into Friday morning. As boundary layer winds transition from west to northwest, snow will impact all of the lake shore. Gusty winds will continue tonight info Friday morning as high pressure rushes in behind the front. 3hr MSL pressure changes increase from 2-3mb/3 hr to 5-6mb/3hr by 15z Friday. Strongest winds winds will be along the lake shore and gust to 40 mph. Travel impacts are expected as the snow and wind combine to produce blowing/drifting. Accums along the lake shore will range from 1-3 inches north of Muskegon to 2-4 south of there. Elsewhere, accumulations around a half inch are possible.

The core of the cold air moves out quickly after 18z Friday and the snow will end.

- Up/down temps through weekend, then warmer

Highs Friday will be in the mid 20s. By Saturday, southwest winds ahead of the next short wave will push temperatures into the mid 30s. Light snow is possible with the short wave north of I-96 but little in the way of accumulations are expected. Behind the short wave Sunday, temperatures will be in the lower 20s.

Sunday looks dry with high pressure in control. A building high over the central US will send heights and temperatures upward next week from the 30s Monday to the 40s Tuesday through Christmas.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1151 PM EST Thu Dec 18 2025

West winds will gust to 30 knots at times through Friday afternoon. Lake effect snow showers begin overnight with areas of IFR persisting into Friday afternoon before tapering off. MVFR conditions prevail through the evening.

MARINE

Issued at 300 PM EST Thu Dec 18 2025

A gale warning remains in effect until 7 am, at which time a small craft advisory will be needed. It's possible that the gale warning will be extended a few hours Friday morning. A tight pressure gradient is in place as deep low pressure moves through the Great Lakes which is producing the strong winds. Wind and waves will be hazardous to small craft through the weekend.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Winter Weather Advisory until 1 PM EST Friday for MIZ037-038-043- 050-056-064-071-072. MARINE...Gale Warning until 7 AM EST Friday for LMZ844>849.