textproduct: Marquette

KEY MESSAGES

- Temperatures will be near-seasonal with highs in the 60s to low 70s and lows in the 40s to low 50s.

- Scattered rain showers tonight, not expected to be widespread or impactful.

- Next chances of rain arrive Friday and Saturday mainly for the south half of the UP.

DISCUSSION

Issued at 300 AM EDT Wed Sep 16 2026

GOES-East Nighttime Microphysics RGB imagery around midnight Eastern shows clear skies across much of the UP except for some high clouds along the Lake Michigan shores associated with moisture transport around a Southeast US ridge with disturbed weather about the periphery of this ridge remaining well to the south of the UP. Elsewhere around North America, 500mb charts show the persistent Hudson Bay trough but otherwise mostly zonal flow across the CONUS and Southern Canada with the exception of a pronounced trough over the Pacific Northwest. For the rest of the overnight period, some patches of fog cannot be ruled out, but HREF probabilities of visibility falling below 1 mile are only 10-33%. While the setup supports effective radiational cooling, widespread dew points in the 40s and low 50s will keep low temperatures in the 40s for most this morning, though a few typical dry/cold spots in the interior west may see temperatures falling into the upper 30s with chances of frost on elevated surfaces at around 10-20%.

As surface high pressure moves directly over the region today, expect light winds with Great Lakes lake breezes in the afternoon and highs in the 60s to low 70s. Meanwhile, a shortwave will move from northern Saskatchewan to far northwestern Ontario throughout today and tonight. This will bring with it a weak surface boundary and chances of scattered rain showers beginning a bit before sunset in the west and spreading east overnight. Rain will not be widespread - HREF probabilities of measurable rainfall tonight are as high as 50-75% along the MI/WI state line and north of Houghton, but between Houghton and the US-41/M-28 corridor, chances are around 15%. Accumulations are not expected to be particularly impactful either, as the 75th percentile of precip totals only exceed 0.1 inches for IMT/ESC and south. The precipitation will contribute to added low-level moisture overnight, which will bring back ~20% chances of fog overnight into Thursday morning.

Ridging in the wake of that shortwave will bring a return of dry weather for the remainder of Thursday into Friday morning with light winds mainly out of the north. Expect highs around the 70s degree mark with lows into Friday morning settling into the 40s away from the Great Lakes. The next chances at rain arrive Friday and Saturday with another shortwave, though the current NBM keeps PoPs above 35% confined to the southern half of the UP and each of the last 3 runs has trended slightly south with the track of precipitation. Current LREF chances of half an inch of rainfall over a 24 hour period are only in excess of 50% for the southern half of Menominee County this weekend, with chances of similar rainfall as far north as the US-2 corridor around 30%. Model spread and forecast uncertainty grows significantly beyond the weekend as ensembles struggle to agree on how the Pacific Northwest trough progresses through the northern CONUS.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 749 AM EDT Wed Sep 16 2026

Other than some fog restrictions early this morning at IWD, VFR will be the prevailing flight category with high pressure over the area. Clouds will, however, increase in the lower levels later today with a chance for rain showers tonight mainly at IWD and SAW. For now, will highlight those chances with PROB30s. Winds will shift throughout the TAF period, but remain light.

MARINE

Issued at 300 AM EDT Wed Sep 16 2026

Under primarily high pressure and only weak disturbances, wind gusts will be sub-20 kt through Thursday evening. Ahead of a stronger disturbance passing south of the region Friday into the weekend, northerly to northeasterly wind gusts in excess of 20 kt briefly become possible (~50% chance) Thursday night into Friday over eastern Lake Superior. During the day Friday through Saturday afternoon, wind gusts to 20-25 kt are expected over far western Lake Superior as easterly and northeasterly winds funnel between the MN Arrowhead and the Bayfield Peninsula. Uncertainty then grows for the late weekend and beyond, though Euro ensemble probabilities of gales are less than 15% throughout the period.

MQT WATCHES/WARNINGS/ADVISORIES

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