textproduct: Grand Rapids

KEY MESSAGES

- Sunday Morning Fog

- Cooler Monday-Tuesday, Then Warming Again

- Chances for Showers Late Week

DISCUSSION

Issued at 338 AM EDT Sun Oct 25 2026

- Sunday Morning Fog

An overnight flow of near-surface moisture off Lake Erie is resulting in another morning of dense fog, this time mainly east of US-127, with patchy/shallow fog possible to the west. The REFS has been handing fog probabilities fairly well the past few nights. Fog potential Sunday night is lower given cloudier skies.

- Cooler Monday-Tuesday, Then Warming Again

A cold front sagging through on Monday will knock temperatures down to closer to normal for Monday and Tuesday. Roughly, highs are favored to be in the mid 50s in Central MI to mid 60s in Southern MI. This front is likely to be dry, although there could be light rain showers or sprinkles in Central MI Sunday night to Monday morning.

There is good agreement among the ensembles for temperatures to rebound Wednesday, back well into the 60s to around 70, as low- level southwesterly flow on the backside of an eastern CONUS high transports 10C 850 mb air overhead. There is the also good potential for this relative warmth to persist through the end of the week/month, though a minority of members (20 percent) cool off highs into the 50s on Friday/Saturday with a deeper eastern Canadian trough or weaker southeast CONUS ridge.

- Chances for Showers Late Week

About a 20-30 percent chance for rain showers amounting to less than a quarter inch returns between late Wednesday and late Thursday, with increasing midlevel moisture and a hint of instability ahead of a weakening cold front. Still too soon to say whether rain will affect Halloween or hold off until after, though PoPs are presently around 40 percent for Saturday evening. There is a fairly large constituency of ensemble member solutions that brings a soaking rainfall (around 0.5 to 2 inches) in early November, as the southern jet stream becomes more active across much of the CONUS.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 653 AM EDT Sun Oct 25 2026

Fog in south-central Michigan has been relatively patchy, with a mix of MVFR tempo LIFR visibility, generally east of a AZO-GRR- MOP line. After 13 or 14 Z, VFR is expected today with clouds above 12,000 feet and light southwest winds. Early Monday morning, MVFR to perhaps IFR ceilings may develop and move south from west-central Michigan in association with a cold front.

MARINE

Issued at 338 AM EDT Sun Oct 25 2026

South-southwest winds 10-20 knots over Lake Michigan this morning will bring 2-4 ft waves into the nearshore north of Grand Haven. Some models including the HRRR have a potential for 20-25 knot wind gusts from the north late tonight around Big and Little Sable Points associated with a cold front. Waves could become hazardous for small craft, around 3-5 feet, on Monday around Big and Little Sable Points, though the greater potential will be over the open waters as the wind direction will be north-northeast.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Dense Fog Advisory until 9 AM EDT this morning for MIZ067-074. MARINE...None.