textproduct: Marquette

KEY MESSAGES

- Another round of showers will moves into the western UP tonight, with a 20-30% chance of thunderstorms over the western and central UP through early Friday morning. Severe weather is not expected.

- Above-average temperatures and mainly dry weather are expected through Labor Day Weekend, with high temperatures in the mid to upper 70s.

DISCUSSION

Issued at 300 PM EDT Thu Sep 3 2026

Afternoon radar imagery shows scattered showers and thunderstorms clipping the southern tip of Menominee County but otherwise remaining south of the state line today as the first in a pair of disturbances passes south through Wisconsin and Lower Michigan. Elsewhere, visible satellite shows mostly clear skies over Lake Superior and the western UP, with temperatures mostly in the 70s across the area as of mid afternoon. The aforementioned secondary disturbance is currently noted on water vapor imagery over eastern North Dakota and will approach the western UP as it tracks southeast into the region late tonight. Models still display quite a bit of uncertainty with regards to timing and placement of this cluster of thunderstorms, with some CAMS keeping activity almost entirely south of the state line while a few others bring thunderstorms into the western and central UP overnight. If the more northern solution were to come to fruition, can't rule out that a few of these storms could initially be on the stronger side as latest HREF depicts up to 1000 J/kg MUCAPE and bulk shear around 40 kt. That said, activity would likely weaken quickly with eastward extent as instability wanes and thunderstorms become elevated with any stronger winds struggling to reach the surface. SPC thus continues to keep the Day 1 marginal risk confined to areas south of the state line through Friday morning, but will continue to monitor how this thunderstorm threat evolves through the evening based on model and observational trends. The quick hitting nature of the system will also tend to limit precipitation amounts, but both NBM and HREF still depict a 50+ percent chance for a wetting rain of a quarter inch over the far west and along the WI border through Friday morning.

Any overnight precipitation should depart the UP by mid Friday morning, leaving mostly cloudy skies and another day of temperatures in the 70s. Guidance continues to depict a few showers being possible over the western half in the afternoon, but would not expect these to be particularly impactful with a less than 15% chance of thunderstorms and minimal QPF. Broad upper level ridging over the central CONUS continues to dominate the pattern through the holiday weekend. As such, temperatures will remain above normal into next week with daytime highs residing in the mid to upper 70s to perhaps the low 80s in a few locations each day. The forecast looks to be mostly on the dry side through the weekend, but precipitation chances increase again early to mid next week as ridging starts to flatten out and makes way for a potentially stronger system to pass through the region. Details are still sparse, but NBM depicts a 50- 70% chance for at least a quarter inch of rain across the UP by early Wednesday, and also depicts a 40-70% chance for wind gust of 40 mph or greater over a wide swath of Lake Superior and the Keweenaw in the same time frame. Will continue to monitor this potential as details hopefully start to come into better focus in the coming days.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 148 AM EDT Fri Sep 4 2026

Multiple round of showers and thunderstorms will move through the U.P. through early this morning. Expect the first round to impact the TAF sites over the next 1-3 hours. MVFR conditions can be expected at IWD and SAW with these showers and thunderstorms. For CMX IFR conditions look likely to develop with easterly upslope flow and low level moisture resulting in lowering cigs. For IWD a period of IFR will be possible as well as during the early morning hours due to low cigs behind departing showers and thunderstorms. This evening, the potential is increasing for ceilings to fall back to IFR at IWD and MVFR at CMX and SAW. Expect light and variable winds for most of tonight before winds turn out of the E/NE at around 5- 10kts during the day Friday. Some gusts to 20kts will be possible at CMX.

MARINE

Issued at 300 PM EDT Thu Sep 3 2026

Lake Superior: High pressure building in from northern Ontario as troughing deepens over the Northern Plains will tighten the surface pressure gradient over the western half of the lake this evening, yielding east to northeast winds of 15-25 kts tonight through Friday. Stronger high pressure building overhead keeps winds light (20 kts or less) lakewide during the weekend, then 20-30 kt winds return next week with a more prominent system lifting to the north of Lake Superior, with the NBM depicting a 40-70% chance for gale force gusts at this time. Wave heights are largely expected to remain at 3ft or less through the weekend, increasing to 2-6ft as winds increase early next week.

Northern Green Bay and northwestern Lake Michigan: Winds generally remain 15 kts or lower through this weekend as high pressure slowly builds overhead. A more prominent system lifting north of the region early next week increases winds to around 15 kts with gusts up to 20- 25 kts. Wave heights are expected to remain below 1ft through the weekend, increasing to 2-4ft with increasing winds early next week.

MQT WATCHES/WARNINGS/ADVISORIES

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