Marine Weather and Tide Forecast for Village of Grosse Pointe Shores, MI

AVIATION

Surface based thunderstorms have about run the course leading up to midnight leaving a stray elevated shower/storm for the rest of tonight. Additional convective clusters farther upstream in WI are expected to also gradually fade while MCS development evolves in the northern Plains into the upper Midwest. The front stalled across central Lake Huron and Lower Mi feeds light west wind over the SE Mi terminal corridor accompanied by pockets of mid and high clouds.
This makes patchy fog possible for a few hours around sunrise leading into a VFR morning across the region. Some form of MCS persistence is expected far enough east for at least the decaying phase to reach SE Mi in the afternoon but is projected east of the area by Friday evening.

For DTW/D21 Convection... The best chance of thunderstorms occurs Friday afternoon as activity moves in from the upper Midwest. Trends will be monitored for strength and intensity forecast refinement in later updates.

THRESHOLD PROBABILITIES...

* Low for ceiling at or below 5000 ft late tonight and Friday.

* Low for thunderstorms Friday afternoon.

PREV DISCUSSION
Issued at 311 PM EDT Thu Jun 19 2025

DISCUSSION...

Clouds and showers this morning into the early afternoon from our departing low pressure system has limited temps and instability thus far. However, the long late June day and developing sunshine, coupled with 500 mb temps lowering to -15 C as another upper level disturbance arrives could prove to be sufficient to generate isolated thunderstorms early this evening with MLcapes 500-1000 J/kg per RAP (assuming temps reaching into lower 70s). 0-6 KM bulk shear under 25 knots will limit severe threat, but precip loaded downdraft strong wind gusts (~50 mph) and hail (<1") look to be in play as wet bulb zero heights reside just under 10 kft.

Big pattern shift this weekend into early next week, as a strong upper level ridge builds over the Central Appalachians, with Euro ensembles indicating 90+ percent probability of 500 mb height reaching aoa 597 DAM by Monday. Sunday and Monday look to be the hottest days over southeast Michigan. Otherwise, possible convection developing during the daytime hours will lead to a lower confidence forecast on the other days. Frontal boundary hangs around the Great Lakes region, and the strength to the cap looks to be weakening next week as the ridge center also looks to be drifting south.

Before we get to the heat wave, upper level trough along the Pacific Northwest/British Columbia coastline looks to direct a strong shortwave through Lake Superior Saturday morning. With the steep mid level lapse rates and southeast Corfidi vectors, there is some concern an organized MCS could make a run toward southeast Michigan on Saturday. At the very least, elevated thunderstorms are possible Saturday morning as ~50 knot jet in the 850-700 mb layer tracks into Central Great Lakes. MUcapes ramping up through the day, above 3000 J/kg, but dry and warming mid levels should attempt to cap activity for the afternoon hours. As such, with southwest flow in the low levels and 850 mb temps reaching aoa 21 C, we should be able to sneak in our first 90 degree day of the Summer.

Heat and humidity only builds further to close out the weekend, with temperatures looking to peak out in the mid to upper 90s based on 23+ C 850 mb temps on both Sunday and Monday. With surface dew pts expected to be in the lower 70s/around 70 degrees, heat indices will exceed 100 degrees, potentially approaching 105 degrees briefly in localized spots. Have included the record high temperatures in the climate section, with the high temperature at Detroit on Monday (June 23rd) appearing to be the lowest hanging fruit and likely to be broken. Heat Advisories at the very least will likely be issued as we get closer, but still potential for extreme heat watch/warning.

MARINE...

Low pressure is in the process of peeling away from the region this evening supporting steadily weakening W/NW winds. Lingering showers (and perhaps a thunderstorm) likewise taper off by late this evening. Friday through the beginning of next work week is characterized by a broad ridge of high pressure building across the central CONUS/Great Lakes. This ridge brings much above normal heat and humidity throughout that timeframe. There are chances for thunderstorm complexes to ride atop said ridge into the Great Lakes offering chances for the central Great Lakes to see continued active weather.

CLIMATE...

The record highs for Sunday, June 22nd.

Detroit: 98 Degrees (Set in 1988)
Flint: 96 Degrees (Set in 1923)
Saginaw: 94 Degrees (Set in 1966)

The record high minimums for June 22nd.
Detroit: 73 Degrees (Set in 1988)
Flint: 71 Degrees (Set in 1988)
Saginaw: 69 Degrees (Set in 2024)

The record highs for Monday, June 23rd.

Detroit: 95 Degrees (Set in 1923)
Flint: 98 Degrees (Set in 1923)
Saginaw: 96 Degrees (Set in 1923)

The record high minimums for June 23rd.
Detroit: 74 Degrees (Set in 1923)
Flint: 71 Degrees (Set in 2013)
Saginaw: 72 Degrees (Set in 1975)

The record highs for Tuesday, June 24th.

Detroit: 97 Degrees (Set in 1952)
Flint: 95 Degrees (Set in 1934)
Saginaw: 96 Degrees (Set in 1938)

The record high minimums for June 24th.
Detroit: 74 Degrees (Set in 1923)
Flint: 73 Degrees (Set in 1997)
Saginaw: 73 Degrees (Set in 1997)

DTX WATCHES/WARNINGS/ADVISORIES

MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.