Marine Weather and Tide Forecast for Grosse Pointe Park, MI

AVIATION

Widespread MVFR ceilings with pockets of IFR exist ahead of a winter system arriving later this evening. Snow is expected to pick up around 03Z or shortly after with a potential for heavy snow in the 05Z to 09Z resulting in widespread IFR to LIFR conditions. P-type starts as snow for all terminals with an expectation across PTK and the southern Detroit terminals for a transition to wet snow/rain mix around 09Z. IFR to LIFR conditions hold through tomorrow morning and possibly into early afternoon. A cold front will pass through tomorrow bringing increasing southwest wind late tonight and then a post frontal gusty northwest wind by early afternoon. Northwest gusts may reach 30 knots at times. The front will also bring a changeover back to snow showers by around 13Z with any light snow showers or flurries tapering off through tomorrow afternoon.

For DTW...Higher snowfall rates with LIFR conditions remain favored between 04Z and 09z tonight before transition to wet snow/rain mix by around 09Z. Transition still carries some uncertainty if colder temperatures prevail. Snow showers then become favored after 13z with decreasing precipitation trend through the late morning and afternoon. A wind shift to NW is currently expected between 17 and 19Z Wednesday with gusts up to 30 knots at times.

DTW THRESHOLD PROBABILITIES...

* High for ceiling at or below 5000 ft through the forecast period.

* High for precipitation type as snow this evening and overnight.
Medium for a transition to rain or rain/snow early tomorrow morning, then high for a transition back to snow after 12Z tomorrow morning.

* Low for ceiling/visibility at or below 200 ft / 1/2 mile overnight.

PREV DISCUSSION
Issued at 411 PM EST Tue Dec 9 2025

DISCUSSION...

Aside from some lingering snow showers/freezing drizzle across the north, main forecast update this afternoon was the southward expansion of the Winter Weather Advisory down to the I-69 corridor.
The 12z model suite showed a notable southward shift in the surface low track, especially in the hi-res data, with the low pressure center shifting as far as 200 miles south compared to previous cycles. This draws the freezing line down toward the I-69/M-59 corridors, allowing a longer duration of snow with lower chances of rain mixing in across the Saginaw Valley/Thumb region. Details discussed below:

1. Areas along/north of the M-46 corridor: A Winter Weather Advisory remains in effect, with snowfall forecasts trending up. With the track of the surface low now projected to be along/just south of this corridor, it is positioned favorably in the northern quadrants of the low to see all snow for a longer duration. Further, there is banding potential given the strong convergence signature along the warm front and steep mid-level lapse rates (3-6km AGL lapse rates over 7 C/km) that would act to constrict and strengthen the frontal circulation. Peak snowfall rates of an inch per hour are possible, primarily between midnight to 6am, with snowfall totals of 3 to 6 inches likely. If banding does develop, we will come close to the 6"/9 hr Warning threshold (e.g. 12z.HRRR solution). A short-fused upgrade to a warning may be needed as observations warrant, especially given that these areas have fallen short of forecast highs this afternoon (still in the upper 20s vs low 30s forecast).

2. I-69/M-59 corridor: The Winter Weather Advisory has been expanded to include counties along the I-69 corridor (including cities of Owosso, Flint, Lapeer, Port Huron). Southern shift of the freezing line supports a longer duration snow with wet bulb zero heights holding aob 2 kft for the majority of the precipitation event. A brief transition to rain is possible, timed around the morning commute, before changing back to snow mid-day as the system moves into Ontario and its cold front settles through the cwa. Rates in excess of a half inch per hour will be plausible, with a high liquid content to the snow (wet snow) as temperatures are near the freezing mark (31- 33 degrees likely). The slight elevation difference of the Irish Hills may warrant additional southward expansion to the advisory into Oakland County, where projected snowfall totals are in the 2-4 inch range.

3. South of M-59 to the Ohio border: no headlines are in effect as there is still confidence in a transition from snow to rain early Wednesday morning. This cuts down on snowfall totals toward 1-2", and will help limit impacts as the changeover is anticipated prior to the morning commute. The period of snow p-type still could see rates of a half inch per hour to result in quick accumulations, although with a melting/compaction component given the warm temps. A lull in precip is expected in the warm sector Wednesday morning as temperatures climb into the mid-30s before falling in the afternoon as the low drags its cold front through Lower Michigan. This will support a changeover back to snow as the system's cold front settles through Lower Michigan, with an additional dusting of snow possible Wed afternoon.

Synoptic precipitation tapers off Wednesday afternoon as the low pushes further into Ontario, leaving northwest flow in its wake that becomes breezy (30-35 mph gusts). Robust mid-level dry slot strips most of the moisture from the DGZ to prevent lake effect activity from surviving this far away from the lakes Wed evening. The one exception will be near the Lake Huron shoreline where lake effect snow showers may linger through the evening. Temperatures fall below freezing by early evening and continue to plummet into the teens by Thursday morning as the thermal trough clips across Ontario. Any residual water (storm total liquid of 0.4-0.6 for reference) will freeze given these temperatures. Wind chills in the single digits are expected Thursday morning.

Quieter conditions are in store Thursday as high pressure builds briefly into the Ohio Valley, but the broad longwave troughing pattern remains a favorable storm track for additional clipper systems and arctic air late week-this weekend. Additional snowfall accumulations and sub-zero wind chills are the main concern.

MARINE...

Strong southerly winds of 20 to 30 knots this afternoon over the Central Great Lakes. Isolated/stray gusts of 32-35 knots even reported by a couple ships over Lake Huron. A surface trough tracking through will allow for winds to diminish and veer to the southwest-west this evening, as milder air also streams in.

A larger and stronger low pressure system remains on track to move through Lower Michigan tonight into Wednesday, producing widespread snow and even rain over Lake St. Clair and Lake Erie. The southwest low level jet ahead of the low looks to be very strong (40+ at 925 mb/50+ knots at 850 mb) toward the southern Michigan border. Still a very difficult call on the near lake surface stability over over the nearshore waters of western Lake Erie, as peak south-southwest winds look to be around 12z Wednesday. With the water temp near freezing over the nearshore waters and surface dew pts rising into the low to mid 30s, anticipate just enough limited mixing to keep gusts to gales less than 3 hours, as winds also look to be more southwest/offshore. As usual with offshore flow nearing gales, there will be heighten concern for low water conditions across the western basin of Lake Erie.

Rush of cold air behind the passage of the low in the afternoon will then support strong northerly winds Wednesday afternoon and early Wednesday evening. There is now another model support to expected frequent gusts to marginal gales over most of southern Lake Huron, and will go ahead with a gale warning. 850 mb temps lowering to -16 C over northern Lake Huron will promote deep mixing and lake induced troughing, which should keep gusts to gales going over the open waters of Lake Huron, at least through midnight, before winds gradually diminish through the rest of the night into Thursday morning. However, a 500 mb low tracking south along the Ontario/Quebec border will re-enforce the cold air, and should maintain sufficient mixing/gradient over Lake Huron to support gusts in the 25 to 30 knot range out of the northwest during Thursday.
Surface ridge building in for Thursday evening/night will lead to much lighter winds, which should linger into Friday as a wave of low pressure track through the Ohio Valley. None-the-less, an Arctic front is on track to move through Friday night, with sporadic gusts to gales possible over Lake Huron during the weekend as 850 mb temps plummet to -20 C, supporting snow squalls and freezing spray as well.

DTX WATCHES/WARNINGS/ADVISORIES
MI...Winter Weather Advisory from 10 PM this evening to 4 PM EST Wednesday for MIZ047>049-053>055-060>063.

Lake Huron...Small Craft Advisory until 4 AM EST Thursday for LHZ422-443.

Gale Warning from 11 AM Wednesday to 3 AM EST Thursday for LHZ363- 462>464.

Gale Warning from 11 AM to 11 PM EST Wednesday for LHZ421-441-442.

Lake St Clair...Small Craft Advisory until 4 AM EST Thursday for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 4 AM EST Thursday for LEZ444.