textproduct: Grand Rapids

KEY MESSAGES

- Warm, Rainy and Windy Today

- Transition back to Snow and Cold Late Thursday, Early Friday

- Roller Coast temps with light snow this weekend

DISCUSSION

Issued at 334 AM EST Thu Dec 18 2025

- Warm, Rainy and Windy Today

Warm air advection continues with warm southerly flow overnight into Thursday. Sfc temps along the lakeshore and through the I 94 corridor remain above freezing with rain expected to overspread the region late morning and through the afternoon. QPF amounts remain around a quarter of an inch to A half an inch.

- Transition back to Snow and Cold Late Thursday, Early Friday

Bottom line upfront. Have issued a winter weather advisory for lake effect snow, flash freeze and gusty winds. Those conditions will cause hazardous driving conditions for Mason and Lake counties, though there is the potential for Oceana and Muskegon.

A strong upper level low will track through the region tonight into Friday morning. That strong upper level trough will coincide with a strong gradient through the mid levels. The biggest concern will be the rapid transition to cold temperatures. 850mb temps go from +5C early evening to -15C by midnight. Couple that with mid level moisture and strong flow across the lake and their is a recipe for decent lake effect snow. Heaviest snow will be through the NW, especially along US 10. The cold air continues to advect overnight into Friday morning with mid level temps dropping to near -20C. Between that arctic air mass moving over a +4C Lake and that if further evidence for lake effect snowfall.

Best snowfall rates should be north of Hart and just east of Ludington and will be in the overnight hours into early Friday morning. The strong LLJ could bring gusty winds as high as 35kts with the snow which could further reduce visibilities. Elsewhere, snow is expected, along with gusty winds, however they will be less in amount and weaker winds.

Snow should taper of mid to late Friday morning as flow weakens and a thermal ridge moves to the east.

- Roller Coast temps with light snow this weekend

That thermal ridge will bring warm air advection into Saturday. However, it will be weaker than today's so highs will rebound only into the mid to upper 30s. Another weak clipper will swing across northern lower MI Saturday into Sunday. Light snow will be possible along the US 10 corridor.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1158 PM EST Wed Dec 17 2025

VFR conditions will lower to MVFR overnight then decrease to IFR on Thursday morning as rain and low clouds move in. South winds will gust over 20 knots along with 50 knots of LLWS. There could be gusts over 40 knots in the afternoon as a narrow line of showers brings strong winds to the surface from AZO to LAN and JXN during the afternoon.

MARINE

Issued at 335 AM EST Thu Dec 18 2025

Winds continue to ramp up overnight and continue to expect an increase to gales Today into Friday. We'll likely need a small craft advisory Friday through Saturday once the gales subside but waves remain high.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Winter Weather Advisory from 10 PM this evening to 1 PM EST Friday for MIZ037-038. MARINE...Gale Warning until 7 AM EST Friday for LMZ844>849.