textproduct: Grand Rapids

KEY MESSAGES

- Showers and Storms End This Afternoon/Evening

- Low Chance Of Weekend Rain

- Additional showers and storms Monday/Tuesday

DISCUSSION

Issued at 230 PM EDT Wed Sep 9 2026

- Showers and Storms End This Afternoon/Evening

Radar shows ongoing showers shifting to the south/east ahead of a cold front expected to pass in the coming hours. The passage of this front will cause showers and storms to come to an end. HREF mean SBCAPE shows a few hundred joules through the afternoon which supports isolated thunderstorm potential until precipitation clears the area.

- Low Chance Of Weekend Rain

Our next chance of precipitation arrives over the weekend as a cold front and weak shortwave cross the area. Weak moisture return is expected to keep much of the weekend dry and PoPs low. For those that see precipitation, amounts should be less than 0.10".

- Additional showers and storms Monday/Tuesday

A stronger system takes aim at the region Monday as the upper-level jet moves south into the region. A deepening low associated with this will lead to potentially breezy conditions as well as the chance for showers and storms. NBM probabilities suggest a 30-40% chance of over 1" of rainfall, highest across the northwest CWA, so will need to monitor for potential heavy rainfall. Given a modeled ample LLJ in place, even with questions on available instability, we'll have to monitor potential for storm development.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 141 PM EDT Wed Sep 9 2026

Generally light rain this afternoon with ceilings dipping MVFR if they haven't already, perhaps temporary IFR. The potential for additional convection developing this afternoon along the back edge of the rain is low but still a possibility as models indicate lingering instability, though limited sunshine and daytime heating today is keeping the confidence for thunderstorms too low to include in the TAFs at this time. Medium confidence for patchy fog early Thursday morning especially in southern Michigan, given wet ground, light winds, and partially clear skies.

MARINE

Issued at 230 PM EDT Wed Sep 9 2026

Observations suggest the Small Craft Advisory/Beach Hazards Statement may be underperforming a bit bit given webcams do show some elevated waves will let the headlines ride until expiration this evening. Another Small Craft Advisory may ne needed Saturday associated with a cold frontal passage.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement until 8 PM EDT this evening for MIZ037- 043-050-056-064-071. MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ844>849.