textproduct: Marquette

KEY MESSAGES

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

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

- There is lower confidence in how Friday's system will impact potential smoke concerns going into the weekend.

DISCUSSION

Issued at 330 PM EDT Thu Jul 16 2026

Afternoon RAP analysis continues to depict northwest flow aloft over the Upper Great Lakes on the periphery of an expansive ridge encompassing much of the central CONUS. This pattern maintains the status quo over the UP today as dense smoke from the upstream wildfires over MN and Ontario continues to drift over the Great Lakes and produce significant visibility reductions and very poor air quality across the region. Smoke has once again held temperatures well below guidance, with afternoon highs ranging from the 60s near Lake Superior to the low to mid 70s elsewhere, save for a few spots in the low 80s in the far west. The Michigan Dept of Environment, Great Lakes, and Energy (EGLE) has extended the statewide Air Quality Alert through Friday given ongoing smoke concerns over the region.

Confidence continues to increase that the UP will receive a widespread wetting rain on Friday as the upper level flow pivots more westerly and paves the way for a shortwave trough to cross the region through Friday night. Ensemble guidance now depicts a an 80- 95% chance for at least a quarter inch of rain across most of the UP through Saturday morning, with closer to a 50-70% chance along the WI border. Some locations could end up seeing much more than a quarter inch in embedded thunderstorms as PWATS climb back above 1.5" on Friday. Speaking of thunderstorms, SPC maintains a marginal risk for severe thunderstorms over the UP on Friday, which certainly appears plausible given bulk shear values increasing above 40 kt. The wild card will be the degree of instability as smoke continues to impact surface heating. Regardless, will be on the lookout for a few strong to severe storms Friday afternoon into Friday evening, with damaging wind gusts and large hail as the primary threats.

In terms of ongoing smoke concerns, the hope is that expected wetting rainfall coupled with stronger southerly winds will help to reduce the amounts of particulate matter and start to mix out the smoke from the low levels of the atmosphere. Hi-res smoke guidance seems to bear this scenario out as it depicts greatly reduced concentrations of smoke during the day on Saturday. Still, much of this will depend on how the incoming system impacts the upstream wildfires to hopefully limit smoke production going forward, as returning northwest winds will otherwise remain conducive to smoke drifting over the region if those wildfire areas do not receive appreciable rainfall. Will continue to closely monitor these developments in the coming days.

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 next Monday.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 152 PM EDT Thu Jul 16 2026

IFR to LIFR vsby will continue due to an expansive area of wildfire smoke from Ontario that has settled in over the region. Winds become southerly by Friday morning but smoke may be hard to clear out as it has expanded well south of the U.P. There is a chance for showers and thunderstorms Friday morning as a disturbance approaches the area. Mentioned the chance for precipitation with PROB30s.

MARINE

Issued at 330 PM EDT Thu Jul 16 2026

Dense Smoke Advisories remain in effect for all of Lake Superior and northern Lake Michigan/Bay of Green Bay through Friday 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 Friday into early Saturday. Otherwise, surface high pressure remains over Lake Superior through tonight, keeping winds below 15 kts area wide. Winds may increase near/above 20 kt at times Friday through the weekend as the aforementioned system moves through, also bringing a potential for thunderstorms.

MQT WATCHES/WARNINGS/ADVISORIES

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

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