Chatham, MI 49816 Weather

Key messages

- Scattered light lake effect rain showers are expected over the eastern U.P. tonight with dry weather elsewhere.

- Mainly dry weather continues through the weekend. Highs in the 50s Friday and Saturday, warming into the low 60s on Sunday and Monday (15-20F above average).

- Precipitation chances increase again early next week. Confidence remains low with the evolution of this system.

Discussion

Issued at 134 PM EDT Thu Oct 29 2026

This afternoon GOES-R water vapor imagery and GFS model height analysis showed westerly flow aloft over the region with large scale subsidence across the U.P. Cold air advection was ongoing in the wake of a low pressure and cold front that pushed across the area last night. With the colder air moving into the region low level lapse rates were steep allowing for gusty winds go mix to the surface, especially over the Keweenaw and near Lake Superior where gusts over 30 mph were common. Clouds were widespread over the northern half of the U.P. while sunny skies were dominant over the south-central. Surface observations showed temperatures in the 40s west to the 50s east.

Tonight into Friday expect temperatures typical of late October with a cooler airmass in place. Lows will be in the 20s away from the Lake Superior shoreline and highs in the 40s to around 50. 850mb temperatures drop into the -2 to -4C range resulting in lake effect rain showers developing over the eastern half of Lake Superior. West- northwest flow will bring any lake effect rain showers onshore over the eastern U.P., mainly east of Munising. With shallow inversion heights and drier air in the low levels any showers should remain on the lighter side. Showers will diminish through the morning Friday as the flow becomes anticyclonic and 850mb temps warm.

A warming trend is expected for the weekend as an upper level ridge builds across the Upper Great Lakes in response to troughing digging across the western U.S. Temperatures will warm into the 50s for Halloween and up into the low 60s for Sunday into Monday. There will be a 20-30% chance for rain showers Saturday evening as a warm front lifts through the region but any showers should remain on the light side and brief.

Monday into Wednesday the West Coast trough opens up and moves east with a surface low developing in the lee of the Central Rockies, then tracking northeast into the Midwest. Forecast confidence remains low with the track of this system, however, overall most ensembles and deterministic guidance favor a weakening surface low as it pushes into the midwest and the upper level trough remains open with a neutral to positive tilt. Blended guidance brings likely rain chances into the U.P. for Monday night into Wednesday with probabilities for >0.5" of rainfall around 40-60% (highest in the south-central, lowest over the far west and Keweenaw). Probabilities for >1" of rainfall remain low over the area, less than 20%, with the higher probabilities remaining well to the south and west, mainly over the Central Plains.

Aviation

Issued at 711 PM EDT Thu Oct 29 2026

Ceilings between FL025 and FL035 continue at all sites this evening, with around 50% chances of above and below the MVFR threshold through about 05Z at IWD and around 09Z at SAW/CMX. Winds become northwesterly tonight and slowly decrease with time.

Marine

Issued at 134 PM EDT Thu Oct 29 2026

Lake Superior: Continued modest pressure rises and cold air advection will bring gusty northwest winds over Lake Superior into this evening with a few gusts to gale over the eastern half of the lake. Winds fall below 20kt over the west by late tonight but remain in the 25-30kt range east of the Keweenaw through the early morning hours. Thereafter winds fall below 20kt and turn southerly Friday night. An extended period of light southerly winds, less than 20kt, is expected for the weekend into early next week.

Northern Lake Michigan and northern Bay of Green Bay: West-northwest winds will gust to 20kt through this evening and then diminish through the night. Winds turn southerly on Friday night with an extended period of light southerly winds, less than 15kt, expected for the weekend into early next week.

Watches, warnings and advisories

Upper Michigan: None. Lake Superior: None. Lake Michigan: None.