textproduct: Grand Rapids

KEY MESSAGES

- Periods of Rain and Thunderstorms Tonight into Next Week

DISCUSSION

Issued at 205 AM EDT Tue Aug 4 2026

- Periods of Rain and Thunderstorms Tonight into Next Week

Dry conditions are expected today with areas to the southeast staying dry into Wednesday afternoon. Our next chance for rain moves in late tonight with a slow moving front. Instability will be limited with the front around 500 J/kg as seen in the HREF and other ensembles. Paired with shear around 20 to 30 knots, not expecting any severe weather into Wednesday. However with the slow moving boundary, synoptic support with the upper level jet divergence and positive vorticity advection, along with precipitable water values increasing to 1.5 to 2 inches there will be a potential for localized spots of 1-3 inches of rain. Areas that see showers and storms repeatedly train over have the best chance of seeing these higher end amounts. The front will slowly shift east of the area Thursday with dry conditions returning Thursday night.

Overall in the upper level flow we'll remain under a broad trough. Within this regime, multiple shortwaves are expected to track through the region bringing additional chances for showers and thunderstorms. Long range ensembles are in decent agreement with most if not all members showing rainfall accumulations over the weekend into next week. Most members highlight 24 hour amounts under an inch, there are a small number of members that show higher amounts up to 2 inches. Not any one day looks to be a complete washout with periods of dry time.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 145 PM EDT Tue Aug 4 2026

SCT to BKN 4-5kft CU field /VFR/ will continue through the afternoon away from Lake Michigan, thanks to diurnal heating and dew points in the low-mid 60s. CU will fade later this afternoon and this evening, as S-SW breezes around 10 kt today become light tonight.

Attention then turns to a weakening cold front currently over WI. This boundary will weaken further and essentially wash-out as it moves into Lower MI early Wednesday. Still, with some moisture pooling along boundary and weak convergence, a small risk for showers warranted at MKG /after 08Z/ and GRR /after 12Z/. These showers may briefly produced MVFR vsbys.

Elsewhere /AZO-BTL-LAN-JXN/ rain-free VFR conditions are expected through 18Z Wednesday with a light S-SW breeze.

MARINE

Issued at 205 AM EDT Tue Aug 4 2026

South to southwest winds with gusts to 25 knots are possible north of Whitehall. A Small Craft Advisory has been issued for late this morning into this evening. Waves will largely be 2 to 3 feet, but 4 foot waves will be possible around 5NM offshore. With these waves a Moderate Swim Risk is expected at beaches between Whitehall and Manistee. South side of piers and breakwalls with be the most susceptible to higher waves and currents.

Lighter winds move in for Wednesday into the weekend. Southwest winds pick up again Sunday and may result in Small Craft Advisory and High Swim Risk conditions.

Thunderstorms will be possible at times late tonight into Thursday and then this weekend into next week. Severe thunderstorms are not expected at this time.

GRR WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory until 10 PM EDT this evening for LMZ848-849.