Marine Weather and Tide Forecast for Marine City, MI

DISCUSSION

A mid-level wave now exiting Missouri will progress east into the southern Ohio Valley this morning which will enhance southerly flow north through the Michigan border, contesting with the broader anticylonic flow from the broad Canadian high pressure over Ontario and Quebec. This will enhance an area of low level convergence from 900mb to 750mb focused along and south of I-94 which will be the focal point for continued rain showers through the morning hours, further aided from weak to modest pva aloft. Shallow forcing within a stable environment will hamper any thunderstorm chances. All precipitation chances wane through the late morning hours as the wave continues to progress east which will quickly dissolve low level convergence while the Canadian high begins to subtly pivot south into the Great Lakes. This will support dry conditions with temperatures topping in the 70s. The slightly cooler temperatures (outside of the vicinity of the lakeshore) will likely be found closer to the MI/OH border given the later departure of cloud cover as deep column moisture needs to be advected and scoured out.

High pressure will provide a dry day tomorrow where despite limited thermal advection, temperatures peak into the upper 70s under modest air mass modification. High pressure will wash out across the continental northeast into the Atlantic on Monday which will allow for some weaker moisture advection to expand across the Great Lakes, but overall synoptic flow is too weak to allow for a meaningful expansion of moisture. A well capped environment with weak gradient flow will likely extend dry weather into Monday as temperatures trends continue to increase, highs peaking in the low to mid 80s.

More active conditions will then return Tuesday and through the midweek period, first as zonal flow ushers in a couple of shortwaves which will bring in some better moisture and will act as a mechanism for shower and storm potential. Otherwise, medium range models are starting to converge on a wave that arrives across around Baja California early next week which will induce lee cyclogensis over the Rockies, producing a low pressure system that has potential to impact the Great Lakes region through the middle of the week. This signal is observed in both the GEFS and EPS ensemble systems, but any specifics to low track/strength will be reserved for when the wave arrives onshore early next week.

MARINE

A frontal boundary remains stalled over the Ohio Valley while broad high pressure over northern Ontario gradually shifts into Quebec this weekend. This pattern sustains light northeast wind, generally 15 kt or less, across the central Great Lakes. Enhanced wind funneling down the axis of Saginaw Bay will reach near 20 knots this afternoon. Showers gradually depart the southern Great Lakes through the day as the high pressure spreads southward - this brings dry weather through Sunday. Generally weak flow persists into early next week with warmer and more unstable conditions arriving on south wind Monday and Tuesday.

PREV DISCUSSION
Issued at 1156 PM EDT Fri Jun 13 2025

AVIATION...

Plume of higher moisture will linger across mainly the Detroit airspace through tonight, north of a low pressure system tracking across the Ohio valley. Gradual decline in cloud base with time overnight will lead to a period of MVFR restrictions across this corridor lasting into Saturday morning. PTK to remain on the northern fringe of this moisture with limited potential to dip out of VFR. Higher based VFR will continue to mark conditions at FNT/MBS tonight, outside of an impacts from the governing low pressure.
Lingering MVFR stratus across the DTW/YIP corridor will lift with time Saturday, with a more expansive coverage of sct/bkn VFR diurnal cu likely throughout SE MI during the afternoon. Winds prevailing from the east-northeast through the period.

For DTW/D21 Convection... Showers will persist through tonight, but limited instability precludes any potential for thunderstorm development.

THRESHOLD PROBABILITIES...

* High for ceilings at or below 5,000 feet overnight through early Saturday. Low Saturday afternoon.



DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...Small Craft Advisory until 4 AM EDT early this morning for LHZ421- 422.

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