textproduct: Grand Rapids

KEY MESSAGES

- Scattered Showers and Storms This Evening Through Thursday

- Mostly Dry Weekend Favored and Heating Back Up

DISCUSSION

Issued at 327 AM EDT Wed Jul 8 2026

- Scattered Showers and Storms This Evening Through Thursday

Overall a decent signal for a few rounds of scattered thunderstorms between late this evening and late Thursday, but fairly unimpressive environment and dynamics that will keep details of predictability low (when and where exactly it will storm) low and also cap potential at just a marginal threat of wind/hail. But the confidence is fair via the HREF for three main windows for storms: late evening weakening storms crossing the lake toward areas north and west of Grand Rapids, then some elevated Thu morning thunderstorms in west-central and central Michigan, then more surface-based storms Thu afternoon east of US-131. Also early this afternoon, can't rule out a weakening thunderstorm surviving into Ludington.

Much about this setup is on the positive but weak side for supporting storms: the sagging cold front, the upper-level jet dynamics, the moistening low-levels and 850 mb moisture transport, the cooling mid-upper levels that will yield about 500-1000 J/kg of CAPE (perhaps more Thu afternoon), and about 20 knots of deep- layer shear. Despite the midlevelds also expected to be rather moist, the well mixed lower atmosphere both this evening and Thu afternoon should support about 500 J/kg of DCAPE per the HRRR, allowing for a chance for a coalesced cold pool to sweep into West Michigan this evening with 30-40 mph gusts, then isolated near- severe wind gusts in mid/southern Michigan Thu afternoon.

- Mostly Dry Weekend Favored and Heating Back Up

PoPs are about 10 percent through the weekend as upper level ridging and surface high pressure is most favored over Lower Michigan. A heat wave is expected to develop this weekend to early next week from the Intermountain West into the Northern Plains, with 500 mb heights potentially reaching 600 dekameters over the Dakotas on Monday per the ECE. This plume of 21-24 C air at 850 mb may advect into Michigan from the west-northwest, making highs in the 90s possible Mon to Tue/Wed. The ECE and CMC are the most aggressive with the heat, and GEFS a little less but still quite warm. Dew points may be in the mid 60s this time, less humid than last week's heat wave.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 655 AM EDT Wed Jul 8 2026

Fog has developed at Holland (BIV), and vicinity Muskegon (MKG) and Fremont (FFX) as seen on webcams and nighttime microphysics satellite images. Patchy shallow fog may also be present in a number of other locations. This fog will mix away quickly with daytime heating underway. Expecting few to scattered clouds at or above 5,000 feet today.

Thunderstorm development in Wisconsin today will eventually move toward MKG and GRR (and north) after 00 Z. Confidence in the storms reaching MKG and GRR is fairly low but worth a prob30. Those storms may bring a northwest wind shift and briefly gustier winds. Scattered thunderstorms may continue to develop into Thursday morning mainly north of MKG, GRR, and LAN.

MARINE

Issued at 327 AM EDT Wed Jul 8 2026

Winds over the water will mostly be from the south-southwest 5 to 15 knots today, though weakening showers or thunderstorms crossing the lake this afternoon and/or evening may cause shifting winds to west/northwest and gusts 20-30 knots or perhaps stronger.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Air Quality Alert until midnight EDT tonight for MIZ050-056-057- 064-065-071. MARINE...None.