textproduct: Marquette

KEY MESSAGES

- Dry and seasonable weather persists today through early Thursday.

- 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 251 AM EDT Wed Oct 14 2026

Early this morning, water vapor reveals a weak midlevel trough dropping southeast into the Great Lakes, while a well-defined midlevel low spins over the Rockies. This northern trough is bringing with it another shot of CAA, with 850mb temperatures already falling to near 0C. Nighttime microphysics shows extensive lower-level cloud cover across the region, in spite of drier midlevels, perhaps due in part to this wave moving through as well as lingering lower-level moisture in the wake of yesterday's rainfall. This is helping to keep temperatures at least a few degrees warmer than previously expected, with temperatures still only in the mid 40s for most expected to fall just slightly further into the lower to mid 40s area-wide. Heading into the daytime hours, the shortwave moves out, to be replaced by a brief period of midlevel ridging and surface high pressure. However, only partially clearing skies are expected as the cooler airmass over the lake may be just enough to support lingering lake clouds. Otherwise, expect highs ranging in the 50s with breezy conditions at least across the eastern UP; there, NW winds may continue to gust to near 20mph through the afternoon. Winds go light tonight while temperatures plummet into the lower 30s and even the upper 20s in the interior- west. If more breaks in the cloud cover occur, these cooler temperatures may become more widespread.

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 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 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 /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 723 AM EDT Wed Oct 14 2026

Primarily MVFR conditions are expected through at least the early afternoon as model guidance suggests MVFR as the most likely flight category (50+%) through about 18Z at all sites. Ceilings gradually improve to VFR in the 21Z-00Z time frame. Expect winds to primarily be out of the northwest until becoming light and variable tonight.

MARINE

Issued at 251 AM EDT Wed Oct 14 2026

Lake Superior: Periods of breezy 15-25 kt NW gusts persist mainly across the eastern half of the lake through this evening. Winds briefly lay down below 15kts tonight into early Thursday before becoming southerly and gusting to around 15-20kts 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 persist through this afternoon, falling below 15kts later this evening. Winds turn southerly 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... Gale Watch from late Thursday night through Friday afternoon for LSZ162-240>242-263.

Gale Watch from late Thursday night through Friday afternoon for LSZ243-244-264.

Gale Watch from Friday morning through late Friday night for LSZ245>251-265>267.

Lake Michigan... None.