textproduct: Marquette

KEY MESSAGES

- Mainly dry weather persists through Monday with high pressure over the area.

- High temperatures trend slightly upward into the upper 60s to low 70s through early next week.

- A few rain showers may graze the western UP this weekend, but chances for more widespread rainfall hold off until next Tuesday into Wednesday.

DISCUSSION

Issued at 209 AM EDT Fri Sep 25 2026

Early morning GOES satellite imagery shows extensive cloud cover over Upper Michigan in association with a shortwave trough crossing northern Ontario. This has helped to limit fog formation relative to last night, with overnight temperatures also running a bit warmer in the low 50s across most of the area. The western edge of the high cloud cover has cleared the far western UP, allowing some patchy low stratus to form in those areas. Skies will gradually clear across the rest of the UP today as the shortwave departs east into Quebec and allows upper level high pressure to rebuild over the region. Highs will trend slightly upward today into the low 70s across much of the area, with the exception of some upper 60s in the Keweenaw and locations near Lake Superior. Dewpoints should mix out nicely again this afternoon, allowing minimum RH values to dip into the low 40s to perhaps the upper 30s in a few interior locations. Do not expect any fire weather concerns given weak pressure gradient and light winds.

High pressure will remain over the Great Lakes through the weekend as part of an Omega-like blocking pattern, bookended by upper lows over the Mid Atlantic and the Canadian prairie provinces. In terms of sensible weather this will more or less maintain the status quo across the UP through early next week, yielding continued dry weather with highs in the upper 60s to low 70s each afternoon. Another weak shortwave riding the western periphery of the ridge this weekend could bring a few showers to the far western UP late Saturday into Sunday, but NBM continues to cap chances for measurable precipitation around 20% near Ironwood. Will need to keep an eye on minimum RH values over the next few days with seasonable warm temps and good afternoon dewpoint mixing, but weak pressure gradient and light winds will continue to limit fire weather concerns.

High pressure finally breaks down Monday into Tuesday, paving the way for more substantive troughing to move into the region during the middle of the week. There is still quite a bit of variability with regards to the details ranging from strength, timing, and orientation of the trough to the potential for a stronger surface low to lift out of the Plains and track close to the area. Despite the model spread, there is broad agreement on more widespread rain returning to the region Tuesday into Wednesday. NBM currently depicts a 30-40% chance for at least a half inch of rain across much of the UP during this time period.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 144 AM EDT Fri Sep 25 2026

Steady high pressure influence keeps VFR the predominant flight condition at the TAF sites during the 6Z TAF period. With variable winds mainly 5 kts or less until the lake breeze arrives this afternoon and gusts holding at or below 10 kts through the period, the focus is on the fog potential early this morning. Guidance has trended back on VIS restrictions at SAW, aligning well with the insulating cloud cover overhead which is expected to persist the next several hours limiting cooling and fog/low stratus development. Downgraded to only MVFR VIS restrictions at SAW. At CMX, cloud cover has already cleared, and METAR reports show signs of LIFR conditions despite low LAMP probabilities (< 20%) of LIFR ceilings and visibility. Thus, leaned on hi-res deterministic guidance for TEMPO groups to LIFR for fog/low stratus formation tonight at CMX, which contain this solution for the current TAF period.

MARINE

Issued at 209 AM EDT Fri Sep 25 2026

For Lake Superior: High pressure will bring light winds of 15kt or less through early next week, mainly from the east and southeast through Saturday and then shifting more southerly Sunday into Monday. A storm system could impact the area Tuesday into Wednesday with cold air advection and a tighter pressure gradient promoting gusty northerly winds. Plenty of uncertainty remains, and current probabilities for gales Tuesday into Wednesday are 25-45%, mainly over the eastern half of the lake.

For the Bay of Green Bay and Northern Lake Michigan: Hazardous marine conditions are not expected through Monday. Expect light winds, 10kt or less, through the weekend with winds mainly from the south-southeast. A storm system could impact the area Tuesday into Wednesday. Current probabilities for gales Tuesday night into Wednesday are only around 5-15%, mainly over northern Lake Michigan.

MQT WATCHES/WARNINGS/ADVISORIES

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