textproduct: Grand Rapids

KEY MESSAGES

- Slight Risk of Storms and Potential Flooding This Evening

- Cooler Than Normal Temperatures Ahead

- Showers and Storms Possible Sunday into Monday

DISCUSSION

Issued at 255 PM EDT Wed Jun 17 2026

- Slight Risk of Storms and Potential Flooding This Evening

There has been some minor changes to the threats this afternoon and evening. While light rain has begun across the region, the axis of heavy rain continues to shift due to the position and track of the low. Latest CAMS are reflective of this. Cooling behind showers that have recently moved through IL and IN and through far SW Michigan has caused a "wake" low and thus gusty winds over southern Lake Michigan. This can be see at the buoys with wind gusts upwards of 57 kts in IL and 42 kts off the coast of IN.

The precip shield and lingering showers have increased stability so will weaken the strength of the winds ability to mix to the surface and the amount they will be able to advect northward. In areas where reflectivities drop then the winds will be able to cycle to the surface and bring some increased wind velocities. Showers and storms will continue to be on the increase as the evening continues. There remains some question on track but latest CAMS brings a few waves of storms through the area due to the low passage this afternoon and evening. There remains some large shear values moving in from the southwest. However, the best shear doesn't seem to be in sync with the best instability. So while there is some weak rotation possible, the best tornado threat remains out of the area though given the shear and winds, a brief gustnado is possible. The main threat will be damaging winds as storms move through between 4 pm to 11 pm. The upper level wave will shift to the east and any lingering precip will fade after 06Z.

- Cooler Than Normal Temperatures Ahead

The large upper level low over Canada will keep cooler air advection into the area through the latter half of the week and keep temperatures lower through that timeframe. Expect highs to struggle to get out of the mid 70s which is 5 to 10 degrees cooler for this time of year.

- Showers and Storms Possible Sunday into Monday

The next shortwave trough ejecting from the western CONUS may develop another surface low over the Plains to Midwest late in the weekend. Depending on the track, another batch of heavy rain could move in later on Sunday. There is some question on the track and timing as is shown through the ensembles. There is the potential it tracks further south and misses MI completely.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 138 PM EDT Wed Jun 17 2026

Prior to the development of thunderstorms this afternoon, we're watching for the potential for wake low induced strong surface winds to potentially develop. Winds have gusted to 48kts at MDW and 55 kts over the lake. Not confident enough to put in the TAFs yet, but we're aware of what's occurring west of here.

A deep low pressure system moving into the region will help to generate strong to severe storms this afternoon. Strong winds are the main threat. Additionally, once the precipitation diminishes this evening, IFR cigs are expected to develop.

MARINE

Issued at 255 PM EDT Wed Jun 17 2026

Several Marine issues today. A wake low moving behind showers this afternoon could bring gale level winds. Several rounds of storms this evening are expected which could prompt special Marine warnings. Winds out of the southwest will shift due west this evening and then to the northwest overnight through the first half of tomorrow. Those winds and waves will allow for SCY conditions along with beach hazards through the first half of tomorrow before subsiding.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement from 2 AM EDT Thursday through Thursday afternoon for MIZ050-056-064-071. Flood Watch until 2 AM EDT Thursday for MIZ064>067-071>074. MARINE...Small Craft Advisory until 4 PM EDT Thursday for LMZ844>849.