Marine Weather and Tide Forecast for Harbor Beach, MI

AVIATION

There is an ongoing influx of post frontal low level dry air which is allowing a clearing of the MVFR deck. The exception to this is around mbS as the southwest flow will sustain a better moisture feed off Lake Michigan into the Tri Cities region, suggesting higher chances of MVFR based clouds and light snow/flurries. In fact, persistent low pressure/troughing across the northern lakes will sustain the low level southwest flow through the TAF period. Some of the low level moisture may filter back into FNT at times, especially tonight and Sunday. The notable push of drier low level air will support prevailing VFR conditions across the Detroit terminals through at least tonight. Post frontal cold air advection supporting a deepening of the boundary layer will sustain SW gusts around 25 knots this afternoon.

For DTW...Model soundings and upstream observations suggest enough moisture present to sustain intervals of clouds based around 5000 feet through the afternoon. While some flurries may be possible, organized snow showers are not expected through the rest of the day and tonight.

DTW THRESHOLD PROBABILITIES...

* Moderate in ceilings aob 5000 feet today. Low tonight and Sunday.

PREV DISCUSSION
Issued at 336 AM EST Sat Jan 17 2026

DISCUSSION...

Lower Michigan sits beneath a stalled upper longwave trough and multiple embedded shortwaves will bring periodic chances for light snow showers throughout the weekend as colder air gradually filters in. Moisture pooling ahead of a cold front pushing east across the state this morning will bring an uptick in light snow coverage mainly south of M-59 and toward the eastern Thumb through about 10AM. Up to around a half inch is most likely with this activity.
Breezy southwest flow will continue to direct the Lake Michigan moisture plume mainly along and north of M-59 which carries the highest confidence in any light snow shower activity this afternoon.
Temps near freezing at press time will fall slightly into the mid/upper 20s for much of the day before the cold air gains more traction and sends temps to the teens tonight.

As the stalled surface low over the northern Great Lakes begins to peel east this afternoon, a passing shortwave looks to help budge the Lake Superior surface trough and send it southeast across northern Lower Michigan. This offers a more defined signal for light snow for the northern Saginaw Valley and Thumb this evening, with around 0.5 to 1 inch of accumulation. Mainly flurries on Sunday as moisture depth remains shallow/disorganized but with occasional bouts of supersaturation within the DGZ. Deeper moisture then accompanies a clipper system Sunday night with widespread light accumulating snow likely across all of SE MI. Ensemble probabilities support a dusting to around 1 inch of accumulation for most, though a few spots getting closer to 2 inches will be within reach.

Much colder arctic air arrives Monday into Tuesday as the core of sub -20C 850mb temps pivot across the area. LREF ensemble probabilities indicate a 40-50% chance for 850mb temps to dip below -25C which is near the daily record minimum per SPC sounding climatology. Blustery conditions will accompany the frigid air mass as high pressure builds into the Ohio Valley, maintaining a stout gradient. Daytime soundings Monday have all the hallmarks of a classic snow squall setup: deep boundary layer mixing up to nearly 10 kft with steep low-level lapse rates, marginal SBCAPE, 30 to 40 kt wind, and supersaturation wrt ice and UVV within the DGZ. Snow shower generation within this environment is supported by synoptic height falls and PVA, low-level fgen, and moisture flux off Lake Michigan. SNSQ parameter above 1 confirms potential for near whiteout conditions at times. The signal for surface convergence suggests highest potential for squall activity will lie within the I- 94 to M-59 corridors.

With the arctic air and persistent gusty WSW wind, wind chill falls below 0F Monday morning and stays below 0 through Tuesday night before rebounding on Wednesday as actual temp rises from the teens to the 20s. Monday night into Tuesday morning remains a target for potential Cold Weather Advisory issuance for parts of the area as low temps bottom out near 0F and wind chill approaches -15F. NAEFS and ECMWF ensemble data shows high confidence in longwave trough persistence over the Great Lakes through the week, favoring continuation of below normal temps despite the slight warm-up midweek. Signal is emerging for widespread snow on Wednesday with the next clipper passing through.

MARINE...

Low pressure exits into ON/QB today with modest southwesterly winds amidst a constricted pressure gradient. This leads to heightened waves across portions of the southern Lake Huron nearshores, thus another Small Craft Advisory was issued. Weak troughing competes with high pressure on Sunday to keep winds and waves elevated. A large and deepening low pressure system races through Sunday night into Monday offering the next opportunity for gusts to gales amidst a strong surge of arctic air. Freezing spray issues are also expected during this very cold and windy period.

DTX WATCHES/WARNINGS/ADVISORIES
MI...None.
Lake Huron...Small Craft Advisory until 4 AM EST Sunday for LHZ421-441.

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