Marine Weather and Tide Forecast for Grosse Pointe Farms, MI

DISCUSSION

Another warm day today with an expanded coverage of high temperatures reaching 80+ degrees (most locations along/south of I- 69). With weak flow in place and differential heating, marine influences will be a significant cooling influence, with lake breezes pushing farther inland through early evening.

Positive tilted progressive upper level trough approaching southern Manitoba border this afternoon, swinging through the Central Great Lakes on Saturday morning. Out ahead of this trough, some upper level energy/weak height falls ejects out of the Midwest on Friday, supporting cyclogensis over southeast Michigan tomorrow. Increasing large scale ascent and destabilization will support blossoming coverage of showers and thunderstorms in the afternoon. ML/1000-850 mb capes increasing aoa 1000 J/kg draws some concern for severe storms. There are some lower 60 dew pts noted over southern Indiana this afternoon which will make a run at or just north of the southern Michigan border tomorrow. However, the surface low pressure is broad and the low level winds are weak, coupled with modest mid level lapse rates (~6 C/KM from 700-500 mb). 0-6 KM bulk shear also borderline south of the surface low, running around 30 knots. On the flip side, the system is ramping up as it tracks through, with phasing occuring as the low pressure system tracks into the Eastern Great Lakes Friday night. With downdraft capes around 1000 J/kg Friday afternoon, a marginal/isolated severe threat seems valid with precip loaded downdraft. Marginal hail not out of the question as well if any cell rotates and sustains the updraft, as machine learning outlook indicating a 5% probability for both wind and hail.

Good shot of cold advection to follow for Friday night, as 850 mb temps progged to reach around zero Saturday morning. With rather tight pressure gradient, local probabilistic guidance suggests northwest winds gusting around 30 mph, supported by Euro ensembles.
Sprawling high pressure builds into the Central Great Lakes through Sunday and then slides east, with an active warm front developing over the Western Great Lakes to close out the weekend. All/bulk of elevated showers expected to stay west of the CWA through Sunday night, as the 700 mb jet core is back across Iowa, per 12z Euro.
Pronounced upper level ridge axis building over southeast on Monday with 850 mb temps reaching 13 C, supportive of highs well into the 70s to near 80 degrees once again with southwest flow ramping up, ahead of a cold front on track to move through on Tuesday. Strong wind fields with the amplified northern stream upper level trough could present a severe threat, but timing is uncertain. Morning timing would mitigate any severe threat.

MARINE

A weak cold front stalls over the region today into tonight with wind 15 kt or below for most of the area. The exception will be Saginaw Bay where northeast flow will quickly ramp up to 20 to 25 kt this afternoon and a Small Craft Advisory has been issued. Low pressure lifts into the region on Friday, bringing scattered to numerous showers and embedded thunderstorms across the central Great Lakes. Moderate easterly flow across northern Lake Huron backs to northerly and spreads southward across the lake as the low departs late Friday. N to NNE wind then peaks late Friday night into midday Saturday with gusts to around 30 knots over central Lake Huron.
Small Craft Advisories will likely be needed as waves build along the nearshore areas in the southern basin. North flow persists through Saturday but gradually weakens as strong high pressure builds in from the west. This high promotes lighter winds and waves through Sunday.

HYDROLOGY

Increasing daytime instability and surface low pressure arriving tomorrow will support showers and scattered thunderstorms developing during the afternoon, as PW values rise aoa 1.25 inches. Although basin average rainfall is generally expected to be a half an inch or less, any strong to marginally severe thunderstorms will produce localized rainfall of 1.0-1.25 inches in a short period which could cause minor urban and small stream flooding.

PREV DISCUSSION
Issued at 201 PM EDT Thu Apr 24 2025

AVIATION...

Favorable aviation conditions persist through the rest of the day with VFR conditions across all terminals. Some high cirrus patches continue to stream in aloft while weak surface winds eventually organize out of the ENE by late evening with the passing of an unremarkable cold front. Low-level winds trend southerly overnight which draws moisture into southern Lower Michigan, gradually saturating the column. A few showers will develop early Friday morning in isolated/scattered fashion as the front briefly stalls near the Michigan/Ohio border. Low confidence in any MVFR ceiling/visibility development with these early Friday morning showers. The front the retreats back toward the north Friday which results in a period of dry conditions midday with southerly winds.

For DTW...A few showers possible early Friday morning with a low chance at MVFR. Isolated/scattered thunderstorms are possible late in the 24-30 hr TAF period with low confidence on timing. Storms more likely to organize linearly toward 00Z Saturday with the passing of the next cold front.

DTW THRESHOLD PROBABILITIES...

* Medium for ceiling at or below 5000 ft Friday.

* Low for thunder late Friday afternoon/evening.



DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...Small Craft Advisory from 6 PM this evening to midnight EDT tonight for LHZ421-422.

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