textproduct: Marquette

KEY MESSAGES

- Patchy dense fog could be seen over the interior central and east until the mid-morning hours. Patchy dense fog could also return late tonight.

- The seasonable temperatures we've seen recently give way to above normal temperatures and humid conditions starting today. The warmer and more humid pattern continues through next week.

- Showers and a few thunderstorms return today, mainly across the south half of the UP. Rainfall amounts generally <0.25 are expected.

- Additional showers and storms are possible through early next week.

DISCUSSION

Issued at 239 AM EDT Sat Aug 29 2026

Isentropic lift in association with an incoming shortwave heads into Upper MI today as some patchy dense fog is already being seen in central Marquette County early this morning (i.e. Gwinn/K.I. Sawyer). While building upper-level cloud cover will help limit fog development across the area, we could see patchy dense fog continue to grow and develop over the eastern interior U.P. before dawn this morning as cloud cover remains somewhat broken still. Looking at the latest medium range and CAM guidance, it does appear that most of the heaviest convection will miss our area to our south today as the shortwave passes. That being said, there is around a 5 to 50% chance that we see over a quarter inch of rainfall between now and 8 PM EDT over the entire Yoop, with the highest chances over the south central and west. While it's certainly not enough to put a serious dent in the drought conditions over the area, at this point we will take anything to help with the dryness! In addition, no severe weather is expected as the instability looks to be too low to develop anything other than heavy rainfall at times (but again, it does look like the heavier rain showers are more likely to miss us to our south today). After the shortwave passes through, expect a general lull in the precipitation late tonight, with patchy dense fog potentially returning across the area.

Another shortwave looks to move through the Upper Midwest on Sunday, but convection chances actually appear to be a little lower over us than in comparison to today's chances; the shortwave may miss us to our south, and even if it doesn't it still may not create enough forcing to get any showers or thunderstorms up. Thus, chances across the U.P. tomorrow range from 10% along Lake Superior to around 30 to 40% in the south central. As additional shortwaves phase from the Plains into the Canadian Prairies, the warm front of the forming low pressure will hopefully bring more showers and non-severe thunderstorms to the area; as of now, the NBM shows this warm front having a 40 to 75% chance of bringing over a quarter inch of rainfall to the area. However, there is some concern in regards to severe weather potential, as there is some modest lift lined up with potentially near-record PWATs (~2.00 inches), a couple thousand J/kg of MUCAPE, and 0-6 km bulk shear around 30 to 40 knots; therefore, the severe weather threat is certainly non-zero for Monday over us as of this current forecast package.

Some additional rain showers and thunderstorms could be seen behind the warm front Monday evening into Tuesday. However, rain chances diminish from the mid-week until near the end of the forecast period as high pressure ridging rebuilds over the central CONUS. Thus, rain chances will be relegated to mesoscale forcing mechanisms (for example, the lake breeze) due to the lack of synoptic-scale forcing. Because warm air from the Gulf is continuing to be pumped over the region behind the warm front, expect the above normal temperatures and humid conditions seen this weekend through early next week to continue through the rest of next week.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 721 AM EDT Sat Aug 29 2026

While VFR conditions do look to generally return by the mid-morning hours, incoming rain showers and thunderstorms today could drop cigs and vis down to MVFR or lower as the latest LAMP guidance shows a 30 to 50% chance of that happening when the convection rolls through each terminal. While the showers and storms look to end by this evening, chances are increasing for fog development over the terminals late tonight; all of the terminals are showing at least a 50% chance for MVFR or lower cigs and/or vis. As for the winds, expect winds to pick up a little from the south today before slacking off and becoming calm late tonight.

MARINE

Issued at 239 AM EDT Sat Aug 29 2026

Lake Superior: Some patchy dense fog could be seen over the eastern open lake early this morning before eroding away by early this afternoon. Meanwhile, an approaching shortwave could bring showers and storms to mainly the southern portion of the lake today before departing tonight; expect winds to remain light at 20 kts or less. Another shortwave moves into the Upper Midwest on Sunday and looks to bring NE to E winds of 20 to 30 kts over the western half of the lake by the afternoon hours. As the winds veer more E over the far west, expect them to decrease with time before increasing back up to 20 to 30 kts from the SE over the eastern half of the lake on Monday ahead of an incoming warm front. Some additional showers and storms could be seen with the warm front's passage, with some severe weather being possible in the worst storms. The winds die down to 20 kts or less behind the warm front, although they may gust up to 20 to 25 kts from the SW on Tuesday over the western half of the lake (mainly between Isle Royale and the Keweenaw). As high pressure ridging builds back over the central CONUS by the middle of the week, expect the winds to remain light at around 20 kts or less for the rest of the week.

Northern Green Bay and northwestern Lake Michigan: Light winds of 15 kts or less build to 15 to 20 kts from the SW today, with showers and storms rolling in as a shortwave comes through this afternoon and evening. While the winds die down to 15 kts or less again by tonight, some patchy fog could form during the overnight hours. Additional showers and storms could be seen on Sunday as well as a second shortwave moves through the Upper Midwest, but chances are currently forecasted to be lower than what they are for today (only a 20 to 40% chance for Sunday). As a warm front moves into the area on Monday, winds look to build to 15 to 20 kts from the SE as showers and storms potentially move through; some severe weather is possible in the worst storms. Winds die down to 15 kts or less again behind the warm front on Monday evening, even as showers and storms continue through potentially Tuesday. As high pressure builds back over the central CONUS, expect generally calmer weather and light winds of 15 kts or less through the rest of the week.

MQT WATCHES/WARNINGS/ADVISORIES

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