textproduct: Marquette

KEY MESSAGES

- Isolated showers linger through this evening, mainly over the eastern half of Upper Michigan.

- Temperatures remain in the mid 60s to upper 70s through Sunday, coolest near Lake Superior. Lower dewpoints will result in more comfortable conditions.

- The chance for showers and thunderstorms returns on Tuesday as a cold front approaches the area.

DISCUSSION

Issued at 359 PM EDT Sat Aug 1 2026

Afternoon RAP analysis depicts a slow moving surface low over Illinois and Indiana, with high pressure beginning to build into Upper Michigan from northern Ontario. Northerly low level flow between these features has kept much of the Lake Superior shoreline shrouded in low stratus and fog through much of the day, although webcam imagery from around the area generally shows fog dissipating and visibility improving as of mid afternoon. Starting to see a few showers pop up on radar along the northern shores of lake Michigan and the WI border near a remnant frontal boundary analyzed through the Mackinac Straits and the southcentral UP. Could continue to see a few rumbles of thunder with this activity into the evening hours given modest instability on the order of 1000+ J/kg MUCAPE per latest SPC mesoanalysis, but would not expect much storm organization given meager wind shear. Any lingering shower activity will wind down tonight, giving way to drier northerly flow as the low and associated upper level trough continue to depart to the east. This will yield clearing skies and likely less fog coverage tonight as drier air works into the low levels of the atmosphere, but still could see some patchy fog in a few spots that have seen recent rainfall.

Expect pleasant sunny conditions on Sunday in dry northerly flow, with highs again holding in the 70s with cooler temps near Lake Superior. Clear skies and low dewpoints will make for a chilly Sunday night as temps dip as low as the low 40s in some interior locations, but do not expect temps to get quite low enough to warrant any frost/freeze consideration. Dry weather persists into Monday under high pressure, with temperatures warming back into the upper 70s to lower 80s as 850 mb temps warm to 15-17 C. The next chance of precipitation then comes on Tuesday as a trough approaches from the northwest and drives another cold front through the UP. This could also bring another round of thunderstorms to the area, but severe potential is TBD given uncertainty over timing and degree of instability and shear. Temperatures look to drop down into the 70s again on Wednesday behind the front, but will quickly recover back into the 80s on Thursday as additional systems bring more chances for precipitation towards the end of the week.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 326 PM EDT Sat Aug 1 2026

VFR conditions have returned to IWD and CMX and will prevail through the TAF period with the exception of possible MVFR fog again tonight at IWD. SAW, on the other hand, has been slow to recover with MVFR/IFR cigs still lingering. SAW should improve to VFR by tonight as low cigs scatter out, but additional BR/FG development tonight can't be ruled out. Otherwise, north to northeast winds of 5 to 10 kts are expected.

MARINE

Issued at 359 PM EDT Sat Aug 1 2026

The lake remains under a weak pressure gradient through the forecast period, resulting in mainly light winds at or below 20 kts. Areas of dense fog have been stubborn to erode over the eastern half of Lake Superior this afternoon. Have extended the existing headlines through this evening, but should start to see some improvement tonight under drier northerly flow. Showers and thunderstorm are expected on Tuesday but there remains uncertainty as to the coverage and strength of the storms.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Dense Fog Advisory until 8 PM EDT this evening for LSZ247>251- 265>267.

Lake Michigan... None.