textproduct: Marquette

KEY MESSAGES

- Well above normal temperatures persist through Monday. Highs well into the 70s are likely for the southern half of the UP on Monday.

- A Red Flag Warning is in effect for Ontonagon and Gogebic Counties through 6 pm EDT/5 pm CDT today. Elevated fire conditions are expected elsewhere across the U.P. until this evening.

- Chances for widespread rain showers with light accumulations Monday evening into Tuesday morning, with higher chances north.

-Temperatures return to near-normal Tuesday.

DISCUSSION

Issued at 330 PM EDT Sun Oct 11 2026

This afternoon's GOES Channel 10 water vapor imagery shows what remains of Isaias penetrating inland to Kentucky while a PNW low works with Tropical Storm Rachel to send moisture streaming northeast toward Ontario and Quebec. Locally, a weak, extended 1005 mb pressure area approaches parallel to the northwestern shore of Lake Superior, and a slightly weakened (relative to yesterday) pressure gradient sits southwest to northeast across the CWA. GRB's 12Z sounding shows an entire column of substantially dry air, including a 900 mb dewpoint depression near 25C. Still in a southerly flow regime with a relatively stacked pressure gradient, winds to 15-25 mph have been observed across the UP today, with higher gusts in downsloping areas along the Lake Superior shoreline up to 30-40mph. RH's recovered well in the eastern UP and poorly in the west last night; values reached 80-95% from Dickinson to Luce County, including the southern half of Marquette, whereas the western UP (including the Keweenaw) reached RHs ranging from 50-65%. So far today, RHs have decreased from there and currently sit at 35-40% in the west and 45-60% in the east. Thus, with the HDW index sitting between the 75th and 90th percentiles for much of the UP today, elevated to critical fire weather conditions continue to manifest. A Red Flag Warning is still in effect for Gogebic and Ontonagon Counties until 5 pm CDT today.

Tonight begins shifting patterns toward cooler, wetter conditions, which should be realized starting Monday night. As high pressure from the northern Canadian provinces fills in and Isaias shifts east toward the DC area, the elongated low dissipates southeastward across the the Upper Great Lakes for the remainder of today and into tomorrow. As this low center drops toward lower Michigan, its place is taken up by a Plains low tracking east along the southern edge of the Canadian high pressure. This means elevated surface winds diminish into the evening today, until northeasterly flow kicks in tomorrow with the approach of the second low from the southeast. Highs tomorrow remain anomalously high (15-20 above normal, except for the Keweenaw, which achieves only climate normal) in the mid to high 70s (50s Keweenaw), and lows tomorrow should be likewise warm in the mid 40s to high 50s (cooler in the Keweenaw). Tuesday at last sees the effects of CAA, with highs in the 50s and 60s -- comparable to tonight's lows!

Monday evening also heralds the arrival of some light precipitation. The plume of Pacific moisture works its way south, and the area may see light rain starting Monday evening (sooner at Isle Royale and the Keweenaw) and continuing into Tuesday morning. Subsequent NBM runs have steadily inched 24-hour QPF totals up, with most of the rain manifesting over Lake Superior, Isle Royale, and the Keweenaw. For the bulk of the UP, though, probabilities of greater than 0.25" of rain ending at 8 AM Tuesday morning now stand between 25-65%, being greater the farther north. A few rumbles of thunder are possible overnight Monday, too.

High pressure moves in Wednesday, bringing a return to dry weather while temperatures trend more seasonal. Towards the latter half of the work week, the general setup among deterministic and ensemble guidance is for another midlevel low to close off and spin over the Rockies while a deepening trough drops out of Alberta. And this is where the similarities end, with some of the guidance showing a phasing of these two systems and a deep low pressure system moving over the UP, while other guidance just brings the more northern wave through. This all brings the potential for more rounds of wet weather into the forecast towards the end of the work week, as well as a shot of colder air into the weekend, though confidence in the finer points is low.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 750 PM EDT Sun Oct 11 2026

VFR conditions ongoing will continue through much of the overnight period at all sites. Late tonight, as winds shift to be out of the northeast, significant low level moisture arrives and ceilings sharply fall for Monday morning. Models are trending earlier and more confident in impactful low ceilings, with most sites at a 50%+ chances of IFR conditions by 12Z. CMX is the only site with above a 15% chance of rain this period, with 25-45% chances of rain between 12Z-19Z. CMX/IWD carry around a 20% chance of occasional LIFR ceiling throughout Monday, with SAW carrying 20-30% chances of LIFR except up to 50% for 12 and 13Z, which may warrant some TEMPO groups in later TAF issuances. The only site with above a 30% chance of visby dropping below 6SM is SAW, which will see a brief period of at least MVFR visby around 12-14Z.

MARINE

Issued at 330 PM EDT Sun Oct 11 2026

Lake Superior: Southerly wind gusts have decreased over the open lake by this afternoon to 20 knots or less, though some Small Craft Advisories remain in place given higher downsloping gusts to 30 knots for another few hours. Winds continue to veer southwesterly and decrease this evening, until flow shifts abruptly north- northeast with the transit of a low pressure center south across Lake Superior. Waves will decrease to near 2 ft tonight before building rapidly in the western arm of the Lake overnight, as sustained winds pick up to 20 knots (gusts to 25 kt) out of the northeast by midnight. Winds remain elevated throughout Monday, with gusts to 40 kt through the afternoon and waves building to 12 feet in the western arm. In the east, expect waves to 9 feet and northeast gusts to 30 knots. Conditions die down through the night on Tuesday as high pressure moves in, with waves subsiding to 5 feet by Wednesday morning and gusts diminishing to below 20 knots, with this decreasing trend continuing into Thursday.

Northern Green Bay and northwestern Lake Michigan: Southerly wind gusts to 20-25kts in the Bay of Green Bay and over northern Lake Michigan continue this afternoon, with wave heights up to 2-4ft in the bay and 4-6ft on the lake side. Winds and waves remain elevated through this evening before beginning early tomorrow morning, reaching 5-10kts by Monday morning with 0-2ft waves. Monday afternoon, winds shift to the northeast while remaining below 10 knots until early Tuesday morning, at which point winds increase up to 15-20 kts as a cold front moves through the area. Elevated winds continue through Tuesday with 1-3ft waves. Winds decrease into the midweek period.

FIRE WEATHER

Issued at 330 PM EDT Sun Oct 11 2026

A Red Flag Warning remains in effect for Ontonagon and Gogebic Counties through 5 pm CDT/6 pm EDT today for critical fire weather conditions. Elevated fire weather conditions are expected elsewhere across the U.P. For the second day in a row, highs are reaching into the low to mid 80s in the interior west (low to mid 70s east). Following last night's poor to good RH recoveries to 50-65% in the west and 80-95% east, RHs this afternoon sit at 30-35% in the west and 40-60% in the east. With continued dry air advection from southerly flow, some pockets may fall further to around 30%. Recovery is expected to be good tonight at 80-100%, being higher in the east. Meanwhile, gusty winds have laid down somewhat today relative to yesterday, being generally less than 20 mph in the west, 25-30 mph in the east, and higher to 35 mph in downsloping areas along Lake Superior shorelines. Southerly winds are expected to continue to decrease to less than 10 mph through the night, until flow shifts northwesterly and gusts to 25 mph build into the Keweenaw in the early morning. Shoreline areas adjacent to Lake Superior may see gusts to 20 mph throughout the day tomorrow, but the bulk of the inland UP should remain below 15 mph. The next chances of rainfall occur Monday evening into Tuesday morning, with 25-65% chance of more than 0.25" by Tuesday morning, and up to 100% chance in the Keweenaw. Northeast flow and cooler temperatures take hold late Monday, with highs Tuesday projected to be in the 50s across the UP.

Minimal recent rainfall and ongoing drought conditions make ignition more likely. Any fire that develops could catch and spread quickly. Members of the public should obey local burn restrictions and report any wildfires by calling 911. Fire partners should continue to monitor forecast updates.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning from 5 AM EDT /4 AM CDT/ Monday to 1 AM EDT /midnight CDT/ Tuesday for LSZ162.

Gale Warning from 5 AM to noon EDT Monday for LSZ263.

Lake Michigan... None.