textproduct: Marquette

KEY MESSAGES

- Breezy conditions persist through the first half of the night, resulting in hazardous swim conditions on the Lake Superior beaches.

- Generally dry weather is expected the rest of the work week, though the UP may be grazed by showers Thursday night into Friday morning. Our next rain chances will return this weekend.

- Cooler temperatures midweek will be followed by a warming trend into the weekend.

DISCUSSION

Issued at 308 PM EDT Tue Jul 21 2026

Early afternoon RAP analysis shows the UP in between deep 992mb low pressure near Hudson Bay and 1022mb surface high pressure sprawled out over the Northern Plains. Though water vapor imagery indicates rather dry midlevel air, plenty of low cloud cover remains over the UP, aided by an unseasonably cool airmass moving over the lake and upsloping into the western and central UP. This helped to kick off light rain showers over the area earlier today, but rain showers and sprinkles are tapering off this afternoon. Winds remain elevated this afternoon behind a cold front, with temperatures already falling into the upper 50s over the northern UP and ranging in the lower to mid 60s to the south. Temperatures turn much cooler tonight than in previous days, bottoming out in a refreshing 45-55F range (coolest in the interior-central) while skies gradually clear out. Under high pressure, Wednesday looks to be an entirely pleasant, if unseasonably cool, summer day with highs ranging in the upper 60s and lower 70s under sunny skies. NW winds start off breezy, gusting to around 20-25mph over the eastern half of the UP, but fall back during the afternoon as our pressure gradient slackens. Expect another pleasantly cool nights as lows range in the mid 50s to mid 50s.

However, as the high pressure flattens and progresses east through the Lower Great Lakes into New England for Thursday into Friday, expect the temperatures to begin climbing back up to above normal (think high temperatures in the upper 70s to mid 80s). As this occurs, a weak ridge-rider may graze the UP with some rain showers and even a rumble of thunder Thursday night into Friday morning. Better troughing arrives Saturday as low pressure moves through Ontario, eventually dragging a cold front through the UP Saturday afternoon and evening. Ahead of this, temperatures climb even higher, possibly reaching the upper 80s in our typically warmer southerly downsloping areas in the western UP and along Superior. Behind this low, upper-level northwest flow looks to keep temperatures somewhat moderated over us into early next week.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 718 PM EDT Tue Jul 21 2026

A high pressure settling southeast over the Midwest brings drier air into the region and slackens winds. This allows for variable winds at IWD tonight and light northwest winds at CMX/SAW around 7-10 kts. Low VFR cigs scatter out tonight becoming mostly clear by Wednesday morning. Scattered clouds return during the day tomorrow as winds remain around 10 kts out of the northwest to west, but VFR prevails.

MARINE

Issued at 308 PM EDT Tue Jul 21 2026

A steep pressure gradient and cold air advection over the lake continues to lead to blustery NW winds this afternoon, with gales to 40kts over the eastern half while gusts come in at around 20-30kts to the west. Winds fall below gale-force around 00Z, then continue to gradually decrease tonight into Wednesday, coming in at around 15- 20kts while shifting over to the W and then SW Wednesday afternoon. SW winds pick up to around 20-25kts across the lake on Thursday and Friday as the high pressure flattens out and heads east towards New England for the latter portions of the work week; strengthening troughing moving in from the west may be enough to have a few showers and thunderstorms develop over the lake Thursday night into Friday. As a shortwave low approaches for this weekend, expect winds to further increase Friday night, potentially getting up to 30 knots or even low-end gales to 35 knots by Saturday morning (up to a 40% chance for low-end gales). In addition, rain and thunderstorm chances increase throughout the day on Saturday as the shortwave passes by.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Beach Hazards Statement until 10 PM EDT this evening for MIZ005-006.

Lake Superior... Gale Warning until 8 PM EDT this evening for LSZ244>251- 265>267.

Lake Michigan... None.