Marine Weather and Tide Forecast for Harbor Beach, MI

AVIATION

Low pressure is quickly departing over Lake Huron this morning with gusty westerly flow left in its wake through the rest of the day.
Gust magnitude will increase to the 25 to 30 kt range by late morning. Dry post-frontal air has brought the return of VFR conditions across parts of the area at press time, but this may be short-lived as additional moisture wraps around the low and potentially reintroduces MVFR over the next few hours. MVFR will be most persistent north of Metro Detroit. Daytime mixing lifts lingering ceilings back to VFR this afternoon. Isolated light showers will be possible through the day but low confidence on timing and brevity of any impact to flight category precludes a mention in the TAF. Winds subside this evening while skies trend mostly clear.

D21/DTW Convection...No thunderstorms are anticipated today.

DTW THRESHOLD PROBABILITIES

* High for ceilings at or below 5 kft through this morning. Moderate this afternoon.

* Low for crosswind operations today.

PREV DISCUSSION
Issued at 402 AM EDT Thu Jun 18 2026

DISCUSSION...

Nocturnal convection is beginning to wind down early this morning as highly anomalous 990 mb surface low pressure (for June) starts to exit, tracking eastward across northern Lower Michigan and into Lake Huron. GOES channel 9 shows the mid-level dry slot spreading northward across the CWA, which effectively concludes lingering elevated showers approaching the lakeshore. The widespread tendency for ascent generated by left exit region jet dynamics has long departed, and in the absence of meaningful elevated instability, remnant MCS/outflow convection has struggled to gain significant depth.

Cyclonic influence does persist today in the wake of the circulation, presenting isolated shower potential through the afternoon hours. Forecast soundings reflect drier mid levels, with even some evidence of warming, but post-frontal boundary-layer lapse rates appear to steepen. This develops from weak cold advection amidst WNW flow, but shallow convective depths preclude any thunder concerns. Although the 120+ knot 300 mb jet core winds ought to reside just south of the Michigan/Ohio state line, a low-level jet of 30-45 knots should overlap much of the forecast area during the day. This favors gusts in excess of 35 mph at times, with the higher frequency/magnitude across the southern half of the region.
Stabilizing ridging/high pressure works in by this evening, ending the potential for showers and weakening the wind field. Mostly clear and cooler tonight.

Low amplitude shortwave ridging offers the highest confidence in a dry day on Friday, at least until Tuesday. A bit warmer, with 850 mb temperatures around 10C, suggesting highs near 70F, but with a diurnal/insolation boost for some into the mid 70s. Weak trough/perturbation within the longwave trough and its surface reflection pass over Lower Michigan Saturday. Waning Pacific moisture marginally helps improve a sub-saturated column, but steeper 700-500 mb lapse rates north of I-69 could be enough to touch off some convective showers during the afternoon hours. To the south, warmer and more stable profiles suggest greater inhibition, but models lack a well defined spatial signal with this activity.

Weak aggregate high pressure emerges on Sunday, preceding a speed max ejecting across The Plains and into the Ohio Valley, perhaps collocated with an MCS. Mid-range guidance is in favorable agreement with timing and track of this wave, such that the bulk of the rain/storm activity should be reserved for the southern half of the CWA Still some potential for a northward extension late Sunday into Monday, and a northern stream upper low could affect the evolution of the wave trajectory. Highs could return to near-normal mid-week.

MARINE...

A strong low pressure system will continue to depart from Lake Huron into Quebec today. Passage of this system will work to reorient winds from the west-northwest through the morning and afternoon hours. An extension of the strong low level jet will hold across Lake Erie, possibly north into Lake St. Clair, and coupled with slightly better mixing depths, brings a window to see some elevated gust potential around 30 knots this morning. Some isolated gust to gales cannot be ruled out leading into the afternoon. Breezy conditions to continue this afternoon and early evening with gusts ranging between 25 to 30 knots. Small Craft Advisories remain in effect for all nearshore locations. Isolated to scattered rain showers will also remain possible with rain chances diminishing this evening. A ridge of high pressure will fill in through Friday which will relax wind speeds for most locations. Some elevated winds will be likely through northern Lake Huron given the northwest fetch.
Periodic rain chances will be possible over the weekend including a low chance for an isolated thunderstorm as multiple upper-level waves cross over the state.

DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...Small Craft Advisory until 8 PM EDT this evening for LHZ421-422- 441>443.

Lake St Clair...Small Craft Advisory until 8 PM EDT this evening for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 8 PM EDT this evening for LEZ444.

Low Water Advisory until 4 PM EDT this afternoon for LEZ444.