textproduct: Marquette

KEY MESSAGES

- Active weather returns Thursday and Friday as a deepening low pressure system works through the Great Lakes bringing periods of rain and gusty N to NW winds.

- Hazardous marine weather is expected Friday. Northerly wind gusts to 50 kts are possible (25-50% chance), creating significant wave heights between 15-20 ft.

DISCUSSION

Issued at 218 PM EDT Wed Oct 14 2026

Afternoon GOES satellite imagery reveals mostly cloudy skies overhead as surface high pressure and localized ridging works into the Upper Great Lakes. A few broken streams of lake enhanced / convergent showers are noted on radar and observations in Marquette County and may be present across the northern tier of the UP through this evening. Otherwise, temps cool into the upper 30s and 40s tonight. Building sfc high pressure keeps quiet weather at bay through most of Thursday before potentially impactful weather returns through the weekend. Additional details below.

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 continue to be in 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. Latest ensemble guidance continues to increase welcomed rain through Friday morning, now suggesting a 75-90% chance for at least 0.5" anywhere in the UP. Early Friday morning through Fri afternoon the surface low feature deepens while departing northeast atop the Lower Lakes, placing Upper Michigan on the northwestern flank. Strong cold air advection and stout pressure rises (upwards of 1-2mb/hr) will contribute to northerly wind speeds reaching 25-35 kts gusting 45-50 kts on Lake Superior and the adjacent lakeshores. There is still some uncertainty regarding the maximum gust potential as ensembles (NBM and ENS) have decreased the probability of Storm Force gusts in the central lake (20-50% chance) and model soundings don't highlight mixing into any 50 kts gust layers. As 850 mb temps cool between -5 to -7C, lake effect/enhanced rain on the backside of the system will provide an additional 0.25-0.5" of precip or the north wind snowbelts and upsloping locations of the west and central high terrain once system rain clears the area. Wouldn't surprise me to see some wet snow mix into areas of the interior highlands early Friday as freezing levels fall ~1000 ft AGL, though the window for any quick show of rain/snow mix is short as soundings show dry air mixing into the the DGZ and sub-cloud layer. 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 some 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. Similar to last weekend's fire weather setup, ensembles suggest a 50-75% chance for S to SW winds gusting to 35 mph in the typical downslope locations of the west and central UP and minimum RHs falling to near 30% in the interior west and central. Luckily, temperatures are only slated to peak into the 60s. Fire partners and adjacent parties should continue to monitor the forecast as containment and mop up efforts for ongoing wildfires may still be ongoing.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 756 PM EDT Wed Oct 14 2026

MVFR cigs likely persist overnight accompanied by calm conditions as high pressure passes overhead. Periods of BKN IFR cigs are anticipated to continue at SAW the next few hours, captured in a TEMPO group. Patchy upslope drizzle may accompany these lower cigs. Conditions deteriorate down to IFR toward the end of the 0Z TAF period Thursday afternoon as another system moves in from the west. Expect rain to arrive at IWD around 16Z, followed by CMX at 19Z, and SAW around 21Z. While periods of LIFR can't be ruled out at all sites Thursday afternoon onward, probabilities were 25% or less so mention was left out. Otherwise southerly winds on Thursday hold around 5 kts with gusts around 10 kts.

MARINE

Issued at 218 PM 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 40-50 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. A Gale Watch is in effect for the entire lake on Friday.

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. A Gale Watch is in effect for all N Lake Michigan marine zones on Friday.

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 Friday evening for LSZ245>251-265>267.

Lake Michigan... Gale Watch from Friday morning through Friday evening for LMZ221-248-250.