Marine Weather and Tide Forecast for Grosse Pointe, MI

AVIATION

West to northwest wind continues across the Great Lakes as the center of surface high pressure builds into the northern Plains tonight. The continued supply of polar air keeps lake clouds activated, however there is also a dry air component that works with NW cloud layer wind to shrink stratocu closer to the shorelines.
This limits lower end VFR to a few streamers or patches of stratocu that are able to make it into SE Mi after broken coverage this evening. High clouds also thicken over the region during the night as the next upper level system settles down into the upper Midwest, ahead of the Plains high pressure. VFR becomes broken below 5000 ft Wednesday afternoon in a combination of stratocu and mid to high level clouds while the next round of light snow holds off until later Wednesday evening.

DTW THRESHOLD PROBABILITIES

* Low for ceiling aob 5000 feet tonight, moderate Wednesday.

PREV DISCUSSION
Issued at 340 PM EST Tue Feb 18 2025

DISCUSSION...

Upper level confluence in left entrance quadrant of upper level jet will provide background support for surface ridging and a relaxed gradient tonight. Warm air aloft will maintain high static stability which should limit much in the way of opaque upper cloud. Eased minimum temperatures downward a touch based on the latest NBM guidance to the lower single digits above zero. With more decoupling of the wind tonight, expecting apparent temperatures to range in the 10 to 15 degree below zero range north of M 59 to the single digits below zero south of M 59. Will not issue a Cold Weather Advisory for tonight.

There is a complexity to the setup for the main vorticity features responsible for the Wednesday night precipitation potential. A deep planetary vorticity lobe of the northern Canada upper level low is forecasted to pivot into the Midwest with subsequent shortwave amplification. Lower confidence exists as the operational ECMWF suggests that a portion of the shortwave energy responsible for the precipitation chances will have had some origin out the Northeast United States storm from this past weekend with the GFS also suggesting some energy originating near Greenland. Quite the tenuous east to west trajectory. Regardless, there has been a consensus that older Atlantic moisture to the north and east of the state will eventually be drawn southward by the aforementioned shortwave and help with fully saturating the column here over Southeast Michigan.
The NAM has been the most aggressive with shortwave amplification and suggests a very well organized corridor of 700-500mb moist isentropic ascent. NBM data suggests plenty of uncertainty with expected QPF of a couple of hundredths, with 50th percentile of snow at no accumulation. For this product issuance will increase PoPs into the likely range with just a few tenths of snow accumulation.

Geopotential heights will rise allowing surface high pressure to build across the Great Lakes for the end of the week and beginning of the weekend. Daytime temperatures will moderate a good amount with readings in the upper 20s Fri/Sat and middle 30s. Low predictability by the end of the weekend as the upper level flow will weaken substantially and turn to the northwest. Latest indications are for multiple shortwaves to pass through that will be very difficult to time.

MARINE...

Frigid airmass in place over the Great Lakes region this afternoon, and winds still gusting around 30 knots over northern Lake Huron, supporting heavy freezing spray with continued localized snow showers. Have extended the heavy freeze warning into the evening.
Winds finally look to decrease significantly tonight as a ridge of high pressure builds in.

Weak/ill-defined pressure pattern for Wednesday will result in predominately light winds, at or below 15 knots.

High pressure tracking south through the Plains Wednesday night and Thursday, coupled with deepening low pressure off the East Coast will result in increasing northerly winds over the Central Great Lakes region for the Thursday-Thursday night, but likely only topping out in the 20-25 knot range per local probabilistic guidance.

Ridge of high pressure slides through on Friday, allowing for at least moderate return southwest flow to develop Friday evening- Saturday. Airmass still looks to be cold enough to support near lake surface unstable profiles, and gusts of 25 to 30 knots seem doable, particularly for Central sections of Lake Huron.

Low pressure looks to be tracking through the Great Lakes region Sunday-Monday, but big differences amongst the models with respect to strength and location. A quick look at the 12z euro ensembles members suggest about a 25 percent chance of gusts to gales over northern Lake Huron. Outgoing forecast/NBM wind grids are much lower for this time period.

DTX WATCHES/WARNINGS/ADVISORIES

MI...None.

Lake Huron...Heavy Freezing Spray Warning until midnight EST tonight for LHZ361>363-462-463.

Lake St Clair...None.

Michigan waters of Lake Erie...None.