textproduct: Grand Rapids

KEY MESSAGES

- Next Chance for Rain late Wednesday

DISCUSSION

Issued at 243 AM EDT Sun Aug 31 2025

- Next Chance for Rain late Wednesday

Overall pattern remains highly amplified and a bit blocky over the next week, more typical of autumn than late summer. We start off with a cool surface high moving east with moderating temperatures as upper ridging builds across the northern Great Lakes through the first half of the week. This is followed by an upper low diving southeast from Canada and carving out a longwave trough across the central and eastern CONUS by late in the week. Moisture streaming up from the south will converge with the trough axis and a surface low trailing a cold front by Wednesday night with showers and a few thunderstorms possible.

Diurnally driven showers with some lake enhancement are possible on Thursday through next weekend with shortwave troughs and vorticity maxima rotating around the upper low in broad cyclonic flow regime along with steep mid level lapse rates. Unusually cold airmass for early September builds in by the end of next week with temperatures again well below normal. Some scattered frost is possible again in the northern interior zones if skies clear and winds decouple from Thursday night into next weekend.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 728 AM EDT Sun Aug 31 2025

VFR conditions will continue through Sunday night. Winds will be light and variable.

MARINE

Issued at 118 AM EDT Sun Aug 31 2025

High pressure will bring light winds and waves a foot or less through mid-week. A Small Craft Advisory may be needed by Wednesday and Thursday as low pressure moves through.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...None.