textproduct: Marquette

KEY MESSAGES

- Scattered rain showers are possible (20-60%) this morning along the southern tier.

- Seasonably warm weather will persist through Labor Day Weekend, with high temperatures expected to be in the mid to upper 70s.

DISCUSSION

Issued at 312 AM EDT Wed Sep 2 2026

This morning's 06Z RAP surface analysis shows the center of the Ontario low sitting at 1006 mb, just west of James Bay. Meanwhile, a positively-tilted surface trough is draped from the Minnesota River Valley toward the Nebraska Sandhills while ridging builds in to the Upper Great Lakes between the aforementioned two features. Per WPC analysis, an occluded front attached to the Ontario low lies across the eastern UP from approximately from Grand Marais toward Door County, WI. Those behind it have some relief from Tuesday's warm muggy conditions, with temperatures in the 50s and 60s and dewpoints depressions ranging from 1-7 degrees. In Schoolcraft, Delta, and Luce counties, however, temperatures tend to be in the high 60s to 70s with dewpoint depressions from 0-4 degrees; the Newberry METAR is currently reporting thick fog.

The main story for today are the scattered showers which will make their way across the southern part of the UP this morning. As the Plains trough progresses east with zonal flow along with continued Pacific moisture, PWAT increases to 1-1.25" for most of the UP and to 1.5" in Menominee County. Most of this moisture, however, is above 700 mb; what precipitation falls out from the relatively weak forcing will have to survive through a stout dry layer to reach the surface. Thus, anticipated QPF resides generally below a wetting rain (0.10"), except for southern portions of Menominee County which may see slightly higher accumulations. High temperatures today should land in the high 70s to low 80s, which, although cooler than yesterday, is still 5-10F above climate normal. Given NW'ly surface flow, areas with onshore flow from Lake Superior may see lower high temperatures.

Much of the remainder of the week will be dominated by upper level ridging over the central CONUS and broad troughing over eastern Canada, leaving the Upper Great Lakes in a fairly benign northwest flow pattern between the two features. The influence of the ridge will be enough to keep temperatures above seasonal norms across the the UP through the period, with daytime highs staying in the mid to upper 70s and overnight lows generally in the mid to upper 50s through the weekend. Do not see any significant rainfall in the forecast beyond Wednesday, but a few disturbances embedded in the flow will at least keep some periodic shower chances around from Thursday into the weekend.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 121 AM EDT Wed Sep 2 2026

VFR conditions prevail for the duration of the TAF period. With drier air and slightly higher wind speeds, opted to leave out mention of fog tonight. There are, however, PROB30s at IWD and SAW for rain showers around daybreak through mid-morning Wednesday. Expect light and variable winds tonight to remain light Wednesday, coming in out of the NW at IWD and CMX while shifting NE behind the lake breeze at SAW.

MARINE

Issued at 312 PM EDT Tue Sep 1 2026

Lake Superior: Winds are expected to remain SW at 15-20kts over the west until 00z this evening, at which point they are forecast to drop to 10-15 kts and shift to a westerly direction. Winds over the east will remain largely southerly at 10-15 knots until around 02z tonight, when they are expect to shift SW. Wednesday, winds will begin westerly, shifting to northwesterly with the passage of the low pressure center to the north. Wind speeds across the lake are expected to remain under 15kts during this time. Wave heights are expected to remain under 3ft through Wednesday evening, although waves up to 4ft are possible between Isle Royale and the Keweenaw.

Northern Green Bay and northwestern Lake Michigan: Winds will remain southerly around 10kts through this evening. During the overnight hours, winds are expected to weaken to less than 5kts and become variable. Wednesday morning, winds remain around 5 kts in a generally southerly direction. Showers, and possibly a rumble of thunder, are possible Wednesday morning. Waves are expected to remain at or below 2ft through Wednesday evening.

MQT WATCHES/WARNINGS/ADVISORIES

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