Marine Weather and Tide Forecast for Sault Ste. Marie, MI

SHORT TERM /THROUGH TONIGHT/
Issued at 240 AM EDT Wed May 21 2025

Current occluding low pressure over Midwest and Great Lakes region continues to spread across the CWA tonight. The leading edge of showers will continue to spread scattered showers northeasterly through the remainder of the short term. Core of low pressure will be tracking across the southern parts of Michigan today before setting up and circulating around Lake Erie Wednesday night and beyond. Advertised rainfall will continue to mainly impact areas south of the M-32 corridor during the daytime Wednesday as vertically stacked low pressure traverses across the southern part of the state. Subtropical midlevel flow over the Ohio Valley continues to cut off efficient advection, leaving precipitation amounts low. The majority of measurable liquid again remains south of M-32 with a wide range of values between a tenth or two and a few localized areas potentially receiving over a half inch. Areas near the tip of the mitt and northward can expect precipitation, but not until late Wednesday night and beyond when the core of the low reaches Lake Erie to wrap rain around the backside. Otherwise, most areas can only expect these cloudy/dreary conditions through the remainder of the work week with highs only in the low 50s today.

LONG TERM /THURSDAY THROUGH TUESDAY/
Issued at 240 AM EDT Wed May 21 2025

Midlevel longwave troughing with closed low pressure will be directly over the CWA at the start of the forecast period. Surface low pressure will continue lingering light and disorganized rainfall this Thursday and Friday as the low remains straddled over the Northeastern CONUS for the remainder of the work week. At the same time... Midlevel riding upstream slowly begins to build over the central U.S and caused troughing to advect to the northeast.
Midlevel heights begin to rise this Saturday along with returning subsidence aloft and subsequent surface high pressure just in time for the holiday weekend.

As for rainfall amounts on Thursday and Friday, unorganized precipitation is expected today with most showers expected to impact areas near and east of I-75 with amounts of a quarter inch or less.
Elsewhere, lesser amount's of a tenth to a trace is anticipated with high temperatures in the 50s for most locations before high pressure builds. Temperatures for the holiday weekend wont return to climatological average for mid/late May, but should remain in the 60s for memorial day.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
Issued at 642 AM EDT Wed May 21 2025

-RA/-SHRA to develop for locations generally south of M-32 today and tonight. MVFR CIGs /VIS likely across KMBL & KTVC as steadier rains push in this morning and afternoon, eventually for KAPN this afternoon and over. -RA makes it into KAPN this afternoon and overnight. Generally dry for KPLN & KCIU with VFR CIGs /VIS. Winds remain breezy as well, generally 15G25KTs today. Little bit of a breeze continues into the nighttime hours, as has been the case the last few nights.

APX WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...Small Craft Advisory until midnight EDT tonight for LHZ345>349.
Small Craft Advisory until 8 PM EDT this evening for LMZ323- 341-342-344>346.