textproduct: Grand Rapids

KEY MESSAGES

- Showers/storms Wednesday, then clearing Thursday

- 70s through Friday, then heat

DISCUSSION

Issued at 200 PM EDT Tue Jun 23 2026

- Showers/storms Wednesday, then clearing Thursday

HIgh pressure and sunny skies this afternoon will soon be replaced by an Alberta Clipper Wednesday; This type of system is usually more indicative of winter through mid spring, but this has been a relatively cool stretch of weather and we've have one more clipper to go before the heat develops.

The clipper is currently nearing the Canada/Montana border and will move across the northern Great Lakes tonight and Lower MI Wednesday. Clouds will advect over the region late tonight and showers and storms will move in either late tonight or early Wednesday. The northwest cwa should see precipitation first. Despite meager mid level lapse rates...5-5.5C/Km...this system will also arrive with a push of moisture. A 35kt llj will move over the cwa Wednesday coincident with a plume of 1.5 inch precipitable water. More importantly, models show 40-45kts of bulk shear Wednesday afternoon. These dynamics should be enough to generate storms and a few could be strong to perhaps severe.

High pressure will build in from the north Thursday and last through much of the weekend before we under a pattern change.

- 70s through Friday, then heat

A deepening upper trough over the northern Rockies will result in a building upper ridge over the Great Lakes late in the weekend and early next week. The increasing heights will result in highs moving through the 80s to perhaps 90; it'll feel more like summer. Dewpoints will also climb into the mid to upper 60s to make it very humid. Apparent temperatures by Monday and Tuesday are likely to be in the upper 90s to lower 100s.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 654 PM EDT Tue Jun 23 2026

Scattered diurnal Cu will diminish over the next several hours with mainly mid and high clouds expected overnight. Expect winds to be light and variable overnight.

Aviation conditions deteriorate late morning into early afternoon Wednesday as showers increase thanks to a nearby warm front. The worst conditions will be where the heaviest shower concentration is, currently favored for MKG/GRR/LAN with lower confidence in restrictions for AZO/JXN/BTL. MVFR conditions are favored in restrictions with a low chance of IFR in heavier showers (10-20%). Thunder probabilities are also low (10-20%) based on NBM/HREF/REFS guidance and marginal forecast instability so will leave thunder out of the forecast. Showers continue and thunder chances increase after 00z Thursday. Winds will increase from the south to around 10 knots as the warm front passes by Wednesday afternoon.

MARINE

Issued at 200 PM EDT Tue Jun 23 2026

Wind will become southerly late tonight and Wednesday and this will result in higher waves over the northern nearshore zones. It's possible we may need a small craft advisory Wednesday afternoon for the northern 2-3 zones. Additionally, thunderstorms will likely develop Wednesday which will pose a threat to boaters and beach goers.

GRR WATCHES/WARNINGS/ADVISORIES

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