Marine Weather and Tide Forecast for Port Huron, MI

DISCUSSION

Elevated showers now pushing into wrn Lower Mi are occurring along the lead edge of a mid level moisture plume and deep elevated mixed layer. This enhanced mid level moist axis will slowly track across Se Mi during the night. Afternoon sfc dewpoints across srn Lower MI are only in the 30s. Ample sub 850mb dry air will remain in place through most of the night. While this will certainly limit shower coverage, weak elevated instability courtesy of 700-500mb lapse rates of 7-8C will still warrant the mention of scattered showers and isolated thunderstorms. The increase in mid/high clouds tonight will limit nocturnal cooling, holding min temps in the 40s.

An influx of low level moisture will occur Wednesday along and south of developing warm frontal feature forecast to become established across the Saginaw Valley and thumb region. Sfc dewpoints forecast to rise into the 50s south of the front will result in weak to possibly moderate instability Wednesday afternoon, aided by continued steep lapse rates in the mid levels. The potential for a few weak short waves rippling across Lower Mi within the mid level westerly flow will support a chance of convection. Some mid level capping resulting from subtle mid level height rises will be a limiting factor for higher pops on Wednesday. South flow and decent mixing depth in the warm sector will boost highs into the 70s across most of the area Wednesday. The Lake Huron marine layer will suppress daytime highs a few degrees across portions of the thumb and Saginaw Valley.

Subtle mid level height rises across Se Mi are forecast to continue into Thursday, while the weak sfc gradient is expected to hold the sfc front across the northern thumb and Saginaw Bay region given the density of the marine layer. A little broader mid level subsidence will support a dry forecast Thursday. Weak warm air advection into the warm sector with decent daytime mixing depths will push highs to near 80/lower 80s Thursday, with much cooler readings near Lake Huron. Variations in timing and amplitude of progressive short wave features across the Ohio Valley and Great Lakes region Friday leads to relatively low confidence on convective timing and chances. There is still plenty of room for additional adjustments within the model solution space over the next few cycles. Ensemble guidance continues to support mild conditions with a high chance of convection. There is strong model agreement in mid level ridging and Canadian high pressure expanding across the region over the weekend, bringing dry and cooler conditions.

MARINE

A weak area of high pressure over the Great Lakes has and will continue to reduce wind speeds over the open waters. Dry weather will persist through the evening, with only a low chance the showers and thunderstorms over Lake Michigan to make it into Lake Huron late tonight into the early morning hours. Expectation are for this activity to decay through the day. Lighter winds continue through the midweek period under the guise of higher pressure and a weaker pressure gradient. Any localized higher wind speeds will be found across northern Lake Huron with the southeast flow, where gusts around 20 knots will be possible by tomorrow afternoon and evening.
The best chances for active weather and elevated winds will come on Friday as the next low pressure system arrives over the state.

PREV DISCUSSION
Issued at 129 PM EDT Tue Apr 22 2025

AVIATION...

High pressure over the Ohio Valley maintains VFR conditions with light westerly surface wind backing and weakening tonight. A series of weak disturbances will bring in mid-level moisture this afternoon through tonight with ceilings likely to stay above 5000 kft. There will be a slight chance for showers across the entire area with low confidence on timing and impact to flight category. The highest probability exists at mbS where the PROB30 group was maintained late this evening. Non-zero chance exists for thunder but too unlikely to include in the TAF. A warm front will migrate over the area on Wednesday, maintaining the mid-level clouds and low-end chances for showers and thunderstorms - mainly during the afternoon.

DTW THRESHOLD PROBABILITIES...

* Low for ceiling at or below 5000 feet tonight and Wednesday.

* Low for thunderstorms Wednesday afternoon.



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