textproduct: Grand Rapids

KEY MESSAGES

- Rain develops Thursday, warmer

- Light snow Thursday night/Friday

- Light snow north Saturday night

DISCUSSION

Issued at 306 PM EST Wed Dec 17 2025

- Rain develops Thursday, warmer

Warmer air will continue to advect northward into the cwa tonight and Thursday. The snowpack will continue melting; we've lost 2 inches since last night at the WFO. Rain will develop late tonight ahead of a strong cold front as strong isentropic lift quickly saturates the column. Models have been consistent for a few days in depicting around 0.4 inches of rainfall before the cold air quickly pours in late Thursday. We'll lose a decent amount of the snowpack, but probably not all of it. At this point we don't see many river issues with the rain. The largest impact may be ponding on roads near clogged storm drains. Highs Thursday will be in the mid 40s.

- Light snow Thursday night/Friday

H8 temperatures quickly fall from +6c to -14c Thursday night. There's roughly 15 hours from 03z-18z Friday where conditions will be favorable for lake effect snow; highest amounts will be west of US-131 and generally north of I-96. However, strong boundary layer winds will push some of the snow showers inland. Accumulations east of US-131 should be a half inch or less.

- Light snow north Saturday night

Lake effect snow showers will end by late afternoon/early evening Friday and high pressure will quickly build into the region. Another cold front will push across the cwa Saturday afternoon. Given the low north of Lake Superior, there won't be a lot of moisture to work with; a 30 percent chance of light snow with the front Saturday north of I-96.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 630 PM EST Wed Dec 17 2025

VFR conditions are ongoing at present, with no significant operational impacts until after 04z. Then, a strong low-level jet with winds in excess of 60 knots moves in around 2kft providing persistent LLWS for potentially much of the TAF period depending on how gusty winds get. Gusts to at least 30 knots are likely beginning late this evening at MKG and early Thursday at the inland terminals. After 09z, MVFR cigs develop as moist air spreads over our snowpack. Rain arrives after 12z bringing widespread IFR conditions, with the worst visbys focused on a 1 or 2 hour window for each site. Given the ample low-level moisture restrictions due to mist persist beyond the showers before the next round of rain arrives.

A cold frontal rain band then crosses the terminals after 17z bringing IFR and potentially conditions to the terminals. Winds may be briefly enhanced along the front as well. Guidance suggests that most improvement in conditions will be after the end of the TAF period behind the front.

MARINE

Issued at 306 PM EST Wed Dec 17 2025

The approach of a deep low pressure system tonight will cause southwest to increase to gales which will continue through Thursday. Thus, no change to the gale warning currently set to begin tonight. We'll likely need a small craft advisory Friday through Saturday once the gales subside but waves remain high.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Gale Warning from 1 AM Thursday to 7 AM EST Friday for LMZ844>849.