textproduct: Marquette

KEY MESSAGES

- Well above normal temperatures persist today with highs well into the 70s for the southern half of the UP.

- Widespread rain showers return tonight into Tuesday morning, with a wetting rainfall expected for most of the UP.

-Temperatures return to near-normal Tuesday.

DISCUSSION

Issued at 303 AM EDT Mon Oct 12 2026

Early this morning, the UP sits on the northern periphery of a midlevel ridge spanning most of the central CONUS, which is directing a plume of moisture from the Plains northward over Lake Superior and Ontario. Closer to the surface, low pressure continues to weaken over the UP, though another surface low is deepening over northeastern CO, while surface high pressure remains sprawled out over central Canada. This has helped to push a frontal boundary southward into the area; it can currently be seen stalled out from around the Bayfield peninsula to the Keweenaw and then northeast across the lake. This will be the focus for our next rain chances later today, but so far, dry conditions persist, with temperatures so far only in the upper 50s and lower 60s still looking to bottom out in the mid the upper 50s for most.

As we head into the daytime hours, the Colorado low begins to move northeastward towards the area, leading to an increasing pressure gradient across Superior and the northern UP. Northeast winds pick up, with gusts up to 20-25mph closer to Superior and possibly up to 30mph over the Keweenaw. After daybreak, chances for rain showers increase over the lake and the far northern UP, closer in proximity to the boundary, as the plume of moisture works southward. Meanwhile, expect high temperatures to range largely in the lower to mid 60s behind the boundary (that is, from around Ironwood to Marquette) while northeast winds limit areas nearer Superior and in the Keweenaw to the 50s. To the south and east, ahead of the front, temperatures peak in the lower to mid 70s, though the south-central UP may climb a bit further into the mid/upper 70s. Rain totals remain quite light before the low moves through the area this evening into tonight, touching off more widespread rain showers across the UP. Subsequent NBM runs have steadily inched 24-hour QPF totals up, with a widespread 0.25-0.50in expected across the UP by Tuesday morning. However, there is around a 50-70% chance for totals in excess of a half inch (highest north), given the potential for multiple rounds of rainfall as well as some embedded thunderstorms. Rain showers quickly wrap up Tuesday morning, while cooler air working in brings a return to more seasonal temperatures. Expect temperatures to climb from morning lows in the 40s and lower 50s to highs in the 50s to mid 60s.

High pressure moves in Wednesday, bringing a return to dry weather while temperatures trend more seasonal while a midlevel low (originating from the deepening trough currently over the Pac NW) parks over the Rockies. Thursday onwards, the general setup among deterministic and ensemble guidance is for that low to slowly move out over the Plains while a deepening trough drops out of Alberta. Compared to 24 hours ago, things are looking a little more progressive, with guidance showing a phasing of these two systems somewhere near the Great Lakes Thursday, resulting in a rapidly deepening surface low over the Lower Great Lakes sometime later Thursday into Friday. As hinted at, there remains a fair amount of uncertainty in the particulars on strength, timing, and track. Still, we do face the potential for more rounds of wet weather 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 /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 104 AM EDT Mon Oct 12 2026

VFR conditions ongoing will continue through much of the overnight period at all sites. As winds shift to be out of the northeast early this morning, significant low level moisture arrives and ceilings sharply fall around sunrise, being mostly IFR at all sites through much of the day. Unlike CMX, which carries 30-50% chances of precip for most of the day, IWD/SAW will likely (85+% chance) remain precipitation free until 00Z. SAW is the only site 30% or more likely to see LIFR ceilings this period. There is a 15-30% chance of weak TS at all sites from 03Z-06Z (as early as 00Z at IWD), but confidence was only high enough to include mention at IWD for this cycle.

MARINE

Issued at 303 AM EDT Mon Oct 12 2026

Lake Superior: Northeast winds are on the increase early this morning, with gusts to 25-30 already becoming common over the western arm. Gales to 35kts are expected to develop there into the pre dawn hours, lingering through the afternoon while waves build to 12 feet. In the east, expect waves to 9 feet and northeast gusts to 30 knots. Gales fall off this evening, then winds continue to die down overnight and into Tuesday as high pressure moves in. Winds fall below 20kts Tuesday afternoon, with waves subsiding to 5 feet by Wednesday morning. However, another shot of cold air working in will allow northwest winds to briefly pick up to around 20-25kts over the eastern half of the lake Wednesday afternoon and evening, with waves increasing to around 3-5ft. Winds fall back again Thursday, but increase rapidly late week with a potential for gales Friday into Saturday.

Northern Green Bay and northwestern Lake Michigan: Winds generally out of the southwest continue to decrease into the pre-dawn hours, falling to around 5-10kts by daybreak. This 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.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning until 1 AM EDT /midnight CDT/ Tuesday for LSZ162.

Gale Warning until noon EDT today for LSZ263.

Lake Michigan... None.