textproduct: Marquette

KEY MESSAGES

- Dry and seasonable weather persists through the midweek period.

- Active weather returns Thursday and Friday as a deepening low pressure system works through the Great Lakes.

- Hazardous marine weather is expected Friday. Northerly wind gusts to 50 kts are possible (50-75% chance), creating significant wave heights between 15-20 ft.

DISCUSSION

Issued at 316 PM EDT Tue Oct 13 2026

Afternoon GOES satellite imagery reveals mostly zonal flow aloft with some weak embedded shortwave action skirting through the region. Lingering moisture and northerly flow on the backside of a departing surface trough is keeping cloudy conditions overhead with areas of fog and drizzle present across the upslope locations of the west and central. High temperatures have only managed to peak into the 40s to low 50s for much of the northern tier of the UP while areas of the south-central climb into the mid to upper 50s. A few light lake enhanced showers are possible tonight across the north and east where 850 mb temps cool between 1-3C. Otherwise, dry and seasonable weather holds through much of the mid-week under a period of mid-level ridging and surface high pressure. Temps tomorrow look very similar to today though some clearing and dry surface air will allow overnight temps to fall into the 30s and 40s overnight.

The main concern of this forecast period continues to be the evolution of a surface low in the Great Lakes driven by two phasing troughs Thursday night through Friday. Operational deterministic models and their ensemble counterparts are in pretty good agreement that a ~1009 mb surface low will be placed in the vicinity of southern Lake Michigan by Thursday evening. Ample northward moisture transport and isentropic ascent ahead of the lead northern stream trough will provide enough support for widespread rain lifting into the UP through Thursday afternoon through Friday morning and latest NBM suggests at least a 50-80% chance for QPF >0.25". Early Friday morning through Fri afternoon the surface low feature is slated to work northeast atop the Lower Lakes, placing Upper Michigan on the northwestern flank. Strong mid to level cold air advection and rapid pressure rises (upwards of 1.5-2mb/hr) will contribute to northerly wind speeds reaching 25-35 kts gusting to near 50 kts on Lake Superior and the adjacent lakeshores. There is some uncertainty regarding the maximum gust potential as ensembles (NBM and ENS) have moderate to high probability (50-70% chance) of gusts >50 kts whereas model soundings reveal peak mixing largely near 45 kts. Lake effect/enhanced rain on the backside of the system will provide an additional 0.1-0.25" of precip once system rain clear the area. Wouldn't surprise me to see some wet snow mix into areas of the interior highlands early Friday morning before temperature warm into the 40s Friday afternoon. No accumulations expected. As winds settle late Friday and dry high pressure clears skies from west to east, temperatures will drop like a rock overnight into Saturday morning, reaching the mid to low 20s for much if not all of the interior while the lakeshores may reach freezing for the first time this fall. Ridging and dry weather dominate through the rest of the weekend with the potential for another warm up / fire weather pattern Sunday into Monday.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 715 PM EDT Tue Oct 13 2026

Abundant low level moisture in the wake of last night's disturbance continues to leave low ceilings and temporary bouts of low visby at all sites overnight tonight. A gradual improvement to MVFR and eventually VFR is expected at all sites as high pressure builds in from the west with chances of IFR or lower conditions after 07Z at less than 1-in-3. Winds remain generally northwesterly at around 5- 10 kt with gusts to around 10-15 kt.

MARINE

Issued at 316 PM EDT Tue Oct 13 2026

Lake Superior: Periods of breezy 15-25 kt NW gusts hold through Thursday before becoming southerly ahead of a strong cold front Thursday night into Friday morning. This strong cold front accompanies a deepening low pressure system that works through the Lower Great Lakes on Friday. Strong cold advection and rapid pressure rises will create sustained winds near gale force with gusts reaching 45-55 kts in the central lake Friday morning. Significant wave heights build between 15-20 feet, highest along the southern lakeshores. Winds and waves slowly subside lake into early Saturday.

Northern Green Bay and northwestern Lake Michigan: Breezy NW winds near 15-20 kts remain through Thursday ahead of a strong cold front that whips through the northern bay and lake late Thurs-early Fri. Northwest winds quickly ramp up between 35-40 kts Friday with waves building between 5-8 ft. Winds and waves subside below gale force into Saturday.

MQT WATCHES/WARNINGS/ADVISORIES

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