textproduct: Marquette

KEY MESSAGES

- "Cooler" temperatures are expected today in the upper 70s along Lake Superior, 80s elsewhere to near 90 in the far southern UP. However, temperatures may realize cooler than forecast depending on wildfire smoke aloft.

- Smoke from upstream wildfires sinks into the Great Lakes today through the rest of the work week. Air Quality Alerts are in effect today. Consider limiting strenuous outdoor activity.

- Temperatures moderate from Wednesday onward, with precipitation chances returning this weekend.

DISCUSSION

Issued at 326 AM EDT Wed Jul 15 2026

Early morning GOES water vapor imagery places Upper Michigan on the northeastern periphery of a stout upper level ridge encompassing much of the lower 48. A subtle shortwave embedded within broader troughing in Quebec has allowed a weak surface cold front to cross the UP, noted by light northwesterly wind observations. A few weak radar returns are also noted reaching the far western UP shores, however, there showers are struggling to maintain themselves given modest dry air in the mid to lower levels. Despite the "cold" frontal passage, it is still quite warm out there with obs hovering in the upper 60s to low 70s as of roughly 3 am EDT.

Headed through the rest of the day, downright oppressive heat will finally no longer be the main threat as upper level heights fall below the 590 dam mark and 850 temps cool to the mid to upper teens. "Out of the frying pan and into the fire" describes the rest of the work week well enough as wildfire smoke from fires burning across the northern MN boundary waters all the way to north of Canada's Lake Nipigon descends into the Upper Great Lakes amidst northwest flow aloft. This makes for a tricky temperature forecast as thick smoke could keep the going blend of 80s 5-10 degrees cooler than advertised. Air Quality Alerts issued by the Michigan Department of Environmental Quality remain in effect today. HRRR vertically integrated and surface smoke forecasts indicate a potentially thicker batch of smoke Thursday, so it would not be a surprise to see these alerts extended further in time. Consider limiting strenuous outdoor activities the next few days.

The stout upper ridge begins to flatten and break down this weekend, allowing the passage of shortwaves and ushering in more seasonable temperatures. Latest ensemble guidance points towards a more widespread rain signal Friday into Saturday, suggesting a 60-80% chance for precipitation amounts >0.25" for much of the UP. Specific amounts will be more contingent on thunderstorm potential, but at this time confidence remains low on the spatial extent and overall timing.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 733 AM EDT Wed Jul 15 2026

Northwest flow aloft has advected in very dense smoke aloft across the northern Great Lakes resulting in IFR vis and cigs across upstream obs and currently at CMX (as of 12z). IFR smoke should be the rule for much of the day, though model soundings suggest we may be able to mix out some of the densest smoke this afternoon and see a brief period of MVFR before another large batch of surface smoke dives across Lake Superior late tonight. CAM ensembles are not much help at the moment handling visibility probs, only suggesting a <20% chance for vis <1 SM through the entire TAF period, but given CMX is already seeing near 1 SM vis and area webcams are rather bleak looking, thinking the chance for <1 SM vis is higher than 20%. Otherwise, winds remain sub 15 kts out of the N to NW.

MARINE

Issued at 326 AM EDT Wed Jul 15 2026

Winds remain below 20kts today through Thursday as ridging recovers over the area. Winds may become elevated to near/above 20kts at times Friday through the weekend with a series of shortwaves moving through, also bringing a potential for thunderstorms. As wildfire smoke from Ontario drifts over Superior today, drops in visibility below 3 SM will be common through the coming days.

MQT WATCHES/WARNINGS/ADVISORIES

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

Lake Michigan... None.