textproduct: Marquette

KEY MESSAGES

- Smoke from upstream wildfires will continue to impact Upper Michigan into this weekend. Air Quality Alerts remain in effect today. Consider remaining indoors when possible.

- An approaching system is expected to bring scattered rain and thunderstorms to the UP today through Saturday morning. A few storms could be strong to severe this evening.

- On and off periods of dense smoke should be expected through the weekend into early next week.

DISCUSSION

Issued at 335 AM EDT Fri Jul 17 2026

Early morning GOES satellite imagery reveals the stubborn broad ridge parked over the central CONUS. A midlevel perturbation is seen descending southeast through the top of the ridge, reflecting a developing surface low pressure across the Dakotas. Ascent ahead of this feature will aid in the development of scattered showers and thunderstorms over the area of active wildfires to our northwest and eventually across much of the UP. However, confidence has managed to decrease regarding the spatial coverage of WAA driven precipitation this morning and afternoon prior to the system's cold frontal passage tonight, where CAMs are more sold on widespread precip/storm coverage. Opting to maintain Slight Chance to chance PoPs across the area, with the greatest coverage over Lake Superior and the northern tier of the UP. 00z CAM ensembles continue to suggest a 50-80% chance for rainfall amounts greater than 0.25", least closest to the WI stateline. As previously mentioned, the greatest confidence in shower/storm activity will likely be focused ahead of the system's cold front, which CAM guidance has trended later into this evening and overnight hours of early Saturday morning. SPC has maintained a Marginal Risk for severe hail >1" and damaging winds, as CAMs suggest healthy instability >1000 j/kg present at the time of arrival coinciding modest bulk shear near 40 kts. However, given the dense smoke concentration over the area, there remain questions surrounding how much diurnally driven surface based instability will be realized and if dry, smokey air aloft may entrain into developing updrafts, altogether limiting severe potential. Gusty south to southwest winds may be able to clear some of the densest smoke out of the western interior UP, as indicated by the most recent HRRR- smoke guidance, but heavy near-sfc smoke is still modeled to stick around much of the area today. Otherwise, a warmer day is expected across the west half with temps climbing into the mid to upper 80s, cooling the further east you go as winds off Lake Michigan keep the eastern third of the UP near 80. Southwest flow will usher in dewpoints back into the mid to upper 60s today, allowing heat indices in the west half to poke 90F. The combination of increased warmth, moisture, and lingering dense smoke may be quite uncomfortable.

The Michigan Dept of Environment, Great Lakes, and Energy (EGLE) maintains the statewide Air Quality Alert today given ongoing smoke concerns over the region.

Modeled smoke concentrations do provide a brief period of clearing behind the cold front late tonight into early Saturday morning, largely across the west half of the UP, but this doesn't last long as north to northwest flow may bring in unhealthy to hazardous smoke concentrations to the region the rest of Saturday. Hopefully scattered showers and thunderstorms provide meaningful rainfall to the wildfires and lessen additional rounds of smoke.

Aside from the lingering questions about smoke, the forecast otherwise looks relatively benign through much of next week as the region settles back into northwesterly flow with temperatures near seasonal norms. There is increasing confidence in another system bringing another shot of rainfall to the area Monday.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 746 AM EDT Fri Jul 17 2026

IFR vsbys continue due to wildfire smoke, and expect that to generally continue into this morning. There is potential for vsbys to improve at least to MVFR by this afternoon/evening as winds attain a southerly component and increase modestly along with diurnal mixing, but confidence in that is low. The other consideration is thunderstorm potential. Scattered showers and thunderstorms are most likely to impact CMX and SAW this morning through the early afternoon, with a secondary line of potentially stronger storms working east to west this evening along a surface cold front. Gusty southerly winds >15 kts will be common at all terminals this afternoon. MVFR cigs may linger intermittently at times tonight but will generally improve during the daytime hours tomorrow.

MARINE

Issued at 335 AM EDT Fri Jul 17 2026

Dense Smoke Advisories remain in effect for all of Lake Superior and northern Lake Michigan/Bay of Green Bay through this evening as wildfire smoke from Ontario and MN continues to drift over the region. Expect visibility to continue to fluctuate below 1 nm at times. Will continue to evaluate whether these headlines need to be extended in future forecast cycles, but there is potential for at least some relief from the smoke heading into the weekend as a system moves through the region today into early Saturday. Gusty southerlies upwards of 25 kts in the eastern half of the lake increase this afternoon ahead of a developing low pressure. This system works just north of the lake tonight, shifting winds to the NW behind the system's cold front overnight through daybreak tomorrow. Showers and thunderstorms are expected to develop along the cold front, which may be strong to severe. NW winds 15-25 kts with a few gusts to 30 kts in the east half linger on Saturday before falling below 15 kts lakewide Saturday night. Peak wave heights between 3-5 ft are possible along the eastern Superior shorelines Saturday.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Dense Smoke Advisory until 8 PM EDT /7 PM CDT/ this evening for LSZ162-240>251-263>267.

Lake Michigan... Dense Smoke Advisory until 8 PM EDT this evening for LMZ221- 248-250.