Marine Weather and Tide Forecast for Port Sanilac, MI

DISCUSSION

Upper level ridge centered (aoa 593 DAM at 500 mb) over southern New Mexico extending north-northeast into the northern Plains. Over lower Michigan, upper level northwest confluent flow with stable low level airmass will lead to the rest of the weekend being dry. Max temps right around 80 degrees tomorrow for most areas, except cooler by Lake Huron/Saginaw Bay/Lake Erie with the easterly flow.

The top of the ridge axis looks to be flattening as some Pacific upper level energy tracks through the Pacific Northwest/northern Rockies. Active warm front over Western Great Lakes Sunday night into Monday, and its possible some elevated showers survive the trip on Monday, but mainly just slight chance pop worthy around around Saginaw Bay. The main 500 mb height fall center looks to be tracking along or just north of western Lake Superior.

A bigger impact to our weather looks to be with the shortwave/height fall center coming out of the Central Plains for the mid week period. There looks to be interaction and eventual phasing with northern Stream energy, as the ECMWF AIFS indicates a seasonably strong surface low tracking through southern Lower Michigan Wednesday night. This would draw concern for severe weather with influx of moisture/instability (MLcapes aoa 1000 J/kg) and noted 45+ knots of 0-6 KM bulk shear. High degree of timing/location and magnitude differences amongst the Euro ensemble members, but majority of the solutions track the low through center or northern Lower Michigan, which would argue for a strong to severe threat Wednesday evening with the deepening low pressure system/strengthening low level jet. Progressive nature of the system should keep the rainfall amounts manageable, as 24 hr qpf props of greater than half an inch are 40-60 percent, with probabilities cut in half for greater than one inch, per euro ensembles.

MARINE

High pressure over Ontario and Quebec dominates the forecast with light northeast wind, generally 10 kt or less, across the central Great Lakes and dry conditions through the weekend. The northeast wind funnels up the axis of Saginaw Bay and locally increases to around 15 to 20 knots each afternoon. Light flow then gains a southerly component by Monday and Tuesday which allows a warmer and more unstable air mass to arrive. A warm front brings the next chance for showers and thunderstorms on Tuesday, and unsettled conditions are likely to continue through the mid-week as several disturbances move through.

PREV DISCUSSION
Issued at 159 PM EDT Sat Jun 14 2025

AVIATION...

Mainly VFR through the forecast as high pressure takes a stronger hold over the region with the low pressure system over Ohio pulling off to the east. A SCT/BKN lower VFR cumulus field will carry through a few more hours over the three Detroit area sites before skies clear out for the rest of the period. Winds will hold out of the east to northeast to around 10 knots or less through this evening before dropping off after sunset.

For DTW/D21 Convection... No thunderstorms expected through this TAF period.

THRESHOLD PROBABILITIES...

* Medium for ceilings at or below 5,000 feet into the afternoon.
Low this evening and tonight.



DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.