textproduct: Grand Rapids

KEY MESSAGES

- Heat Risk Gradually Diminishes

- Chances for Storms Continue Through the Holiday Weekend

DISCUSSION

Issued at 313 PM EDT Thu Jul 2 2026

- Heat Risk Gradually Diminishes

Subsidence and drying from this morning's dying convective system has left behind dew points in the mid 60s in central MI, while closer to I-94, dew points are still in the mid 70s with heat indexes around 100. With the exception of Ludington, it's still hot, but the somewhat drier air gives an opportunity to chisel away at the Extreme Heat Warning along and north of a Muskegon to Clare line. The remaining warning will turn over to a Heat Advisory this evening through Friday morning as moderate to high heat risk continues as the heat wave potentially stretches into a fifth day in southern portions of Michigan. While some noticeable humidity will remain, models are locked in on temperatures trending closer to normal by early next week, given the weakening of the SE US heat dome and a tendency for weak upper level troughing over the Great Lakes.

- Chances for Storms Continue Through the Holiday Weekend

Unsettled weather continues with fairly low confidence in the predictability of thunderstorms given weak forcing mainly driven by upstream convective complexes and their associated induced atmospheric waves. The drier air and strong cap present this evening will keep the chance of storms very low, though can't rule out a shower popping up near Battle Creek or Jackson. The storm complex in eastern Iowa will track toward west/southwest Michigan for late this evening/tonight, though its intensity when it arrives is very much in question. Any threat would primarily be wind, as there will be weak cloud-layer shear but substantial DCAPE.

The chances for additional storms remains for Friday afternoon/evening, particularly in southern Michigan, followed by scattered storms popping up through the remainder of the weekend as a larger-scale weak upper level trough deepens over the Great Lakes. A majority members of the ECE and GEFS are fairly bullish on the precip chances through at least Saturday night.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 216 AM EDT Fri Jul 3 2026

VFR weather is in place across most of the region at 06z. The exception is in some very localized thunderstorm activity across the Southern Great Lakes stretching from Northern Illinois into Southern Lower Michigan. Isolated to scattered thunderstorms are expected to continue across Southern Lower Michigan the rest of the night impacting the I-94 TAF sites. The I-96 TAF sites will likely remain north of the activity. A lull in the showers/storms will likely occur during the morning hours of Friday after sunrise. During the afternoon and evening we expect another round of showers and storms to mainly affect the I-94 TAF sites between roughly 20z and 03z. Winds will be southwest at 5-15 knots today with some gusts to around 20 knots in the afternoon.

MARINE

Issued at 313 PM EDT Thu Jul 2 2026

Mostly a lighter south/southwest flow over the lake has kept us out of beach hazards today. Smaller zones of 15 knot winds over the lake could build waves to 2 to 4 feet with a moderate swim risk this afternoon between Muskegon and Ludington. Otherwise, outside of any thunderstorms, a lighter wind regime through the holiday weekend will keep wave hazards low.

There is a chance of scattered thunderstorms crossing the late tonight and again later in the day Friday. Wind gusts and lightning will be the main threats.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Heat Advisory until 8 PM EDT this evening for MIZ046-051-052- 056>059-064>067-071>074. MARINE...None.