textproduct: Grand Rapids

KEY MESSAGES

- Chances for thunderstorms once again today

- Dry weather Monday Night through Wednesday

- Showers and storms possible Wednesday night and Thursday

DISCUSSION

Issued at 415 AM EDT Sun Jul 5 2026

- Chances for thunderstorms once again today

Multiple meso vorticity maxima have rotated eastward across Northern Indiana tonight. This has produced a zone of convergence over far Southern Lower Michigan, including the I-94 corridor. The FV3 seems to have the best handle on this and we expect to see an uptick in coverage and intensity over the next few hours or through 12z-13z. Deep layer shear is very weak and instability is not strong (500-1000 j/kg). So, while we expect a few storms early this morning we are not anticipating anything close to severe.

A surface low will be just south of the region today over IN/OH. There may be just enough lift and instability to see another small round of storms this afternoon and evening from Holland to St. Johns southward. The HREF shows this well. Cannot rule out some locally heavy rain today near I-94 with the HREF indicating some localized swaths of 2-4 inches possible. Most areas will not see this much, but with convergence and high PWATs these values are reasonable in an isolated max forecast.

Chances for showers will persist tonight and into Monday across the far southern CWA as the low to our south does not move much.

- Dry weather Monday Night through Wednesday

We look to be dry Monday night through Wednesday with high confidence in ridging persisting over the Great Lakes. BUFKIT overviews show very little moisture in the profile. Highs in the 80s and lows in the 60s will feel more comfortable, especially with lower dew point air settling in on northeast winds.

- Showers and storms possible Wednesday night and Thursday

Our next chance for rain will come Wednesday night and Thursday as a cold front presses in from the northwest. Surface dew points will rebound to 65F to 70F which will push MUCAPE values to in excess of 1000 j/kg. Thunderstorms will certainly be possible once again during this time frame.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 139 PM EDT Sun Jul 5 2026

Radar shows scattered light showers near the terminals and moving southwest. Forcing remains present over the region with a surface low moving across IN and an upper trough poised to move across the lake. Daytime instability could still generate a storm or two, but mainly over the southern TAF sites.

Given the recent rain along/south of I-96, some low ceilings and reduced visibilities in fog are possible overnight.

MARINE

Issued at 415 AM EDT Sun Jul 5 2026

Winds for the most part will be light over the next 4 days. There will be some stronger off shore winds tonight in the 10-20 knot range, but they will be northeast/off shore. Therefore, waves over the next 4 days in West Michigan will largely be 2 feet or less in the nearshore waters.

The one item to watch in the next few days is that Monday could feature our advancing high scenario where we see higher than forecast winds and waves. It would be centered on Monday afternoon and early evening.

GRR WATCHES/WARNINGS/ADVISORIES

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