textproduct: Grand Rapids

KEY MESSAGES

- Scattered afternoon/evening storms north

- Building heat

DISCUSSION

Issued at 136 PM EDT Thu Jun 25 2026

- Scattered afternoon/evening storms north

Radar shows scattered convection as developed over the northern cwa near US-10. We'll continue to monitor for the potential for isolated severe storms as there is sufficient instability, moisture, but marginal shear values. These showers/storms will dissipate after sunset.

- Building heat

The developing story across the Great Lakes will be the building heat that will likely result in heat headlines next week.

A deepening upper trough over the northern Rockies will result in a building ridge over the central US including the Great Lakes. H8 temperatures are expected to increase from 18C Monday to 24C late Tuesday. That type of heat will send surface temperatures into the lower to mid 90s for much of next week. Most models increase dewpoints into the lower to mid 70s during the heat wave which will make the air feel incredibly humid. The high heat and humidity may result in scattered convection if the cap doesn't become too strong. Overall, though, we don't anticipate much precipitation next week due to short waves riding over the top of the ridge well north of the cwa.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 103 PM EDT Thu Jun 25 2026

Any lingering MVFR cigs will scatter out over the next hour or two with VFR conditions then expected through the evening. Any showers and storms this afternoon are forecast to stay north of the terminals. Gusts to 20 knots will continue until near sunset. Tonight, light north- northeasterly flow off of Lake Huron will support low clouds and patchy fog afer 08z with a mix of MVFR to IFR expected. Some guidance is a bit more aggressive on reductions overnight so moisture trends will need to be monitored. Any fog/low clouds will mix out Friday morning.

MARINE

Issued at 136 PM EDT Thu Jun 25 2026

A weak pressure gradient will limit marine issues as we move toward the weekend. However, dewpoints in the 70s over cold water may result in dense fog by the end of the weekend through much of next week.

GRR WATCHES/WARNINGS/ADVISORIES

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