textproduct: Marquette

KEY MESSAGES

- Temperatures trend toward normal tomorrow, with highs 50s north and 60s south, and are likely to remain seasonable through mid-week.

- An Air Quality Alert is in effect for Baraga, Marquette, Iron, Dickinson, and Menominee Counties due to large, ongoing wildfires. Localized pollutant levels in those areas may reach Unhealthy for Sensitive Groups with potential for Unhealthy.

- A wetting rainfall (0.5") is expected for much of the U.P. tonight into tomorrow morning, with higher amounts expected across the north.

DISCUSSION

Issued at 352 PM EDT Mon Oct 12 2026

Regional RAP surface analysis through the day shows a 1002 mb low entering Minnesota from Nebraska, and GOES imagery shows cloud cover overspreading much of the UP. Radar has shown sporadic cells over Lake Superior transiting eastward; MRMS indicates light accumulations so far today, mostly occuring over Isle Royale, the Keweenaw,and Lake Superior. Most amounts are less than 0.2 inches but some isolated spots have received up to 0.35 inches. Fog and mist beneath low ceilings are common today, particularly in northeast flow upslope areas. Temperatures have turned toward seasonable; the Keweenaw remains stubbornly in the 40s, while southern Menominee County has reached the 70s, and elsewhere falls somewhere between the two.

The rain thus far today comes courtesy of a plume of moisture with nearly zonal motion along the US-Canada border, which has descended slowly south while navigating around the southern edge of a Hudson Bay High. Tonight, further precipitation is anticipated along with better forcing and higher accumulations as the Minnesota low transits toward and then south of the UP. Per the REFS, the probabilities of receiving greater than 0.25" through Tuesday 8 AM north of a line from Gogebic to southern Schoolcraft County is 100%; chances south of this line are much less, decreasing to 15% in southern Menominee County. For 0.6", only a few areas in northern Marquette and Baraga Counties show 100%, with elsewhere showing less and southern Menominee County at 0%. Thunderstorm potential has trended up over the past 24 hours, with CAMs in good agreement and now showing scattered cells across the UP through the night. With up 500-700 J/kg of MUCAPE (REFS mean) and 1.3 - 1.5" of PWAT available to work with overnight, some areas may see higher accumulations as stronger cells develop.

Lows tonight remain anomalously high in the 40s north and 50s south, as northeast winds work through previously advected warm air in southern Ontario. This transitions into a brief WAA regime late tonight as the Minnesota low approaches from the east, reinforcing above-normal lows tonight. Temps return to normal as this low wraps in cooler air on its backside through Tuesday, leaving temperatures in the 50s for most of the UP, though the southern UP may hit the upper 60s. Overcast or nearly overcast skies dominate for the next few days.

With several large, ongoing wildfires and suppression efforts under way, an Air Quality Alert is in effect today for Baraga, Marquette, Iron, Dickinson, and Menominee Counties. Localized pollutant levels in those areas may reach Unhealthy for Sensitive Groups with potential for Unhealthy. Note that in areas of fog, such as upslope areas of Marquette and Baraga Counties, it may be difficult to distinguish smoke from fog while driving or outdoors. Sensors may not pick up on air quality reductions due to localized nature of smoke plumes.

After tonight's precipitation, dry conditions should once again be the norm for a few days as high pressure builds in Wednesday into Thursday. A much colder airmass is projected to arrive Friday as an Alberta clipper digs into the Great Lakes region. At this time, both the GFS and Euro show remarkable agreement that this clipper will phase with a Colorado low swinging north right around 12Z over the lower Great Lakes, generating a steep pressure gradient with northerly flow over Lake Superior. Multiple ensembles hint at strongly elevated wind potential during Friday. While the jury's still out on whether or not this pattern will generate storm-force winds over Lake Superior (less over land, but likely still elevated), the ECMWF, Canadian, and GFS ensembles agree that some form of elevated sustained winds, possibly up to gale- force, may occur. Soundings show a cold airmass well below 0C being advected in with deep mixing, reinforcing this notion. Details of this event will continue to evolve.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 201 PM EDT Mon Oct 12 2026

VLIFR fog to MVFR conditions are present this afternoon across the UP with the worst conditions at CMX/SAW in upslope flow, while clearing to scattering skies slowly inch towards IWD. IWD will likely lift to VFR this afternoon before all sites are expected to plunge back into the soup tonight ahead of a northward lifting area of low pressure and widespread precipitation development. Widespread scattered showers and even a few thunderstorms work from west to east around 00z, reaching CMX and SAW a few hours later. Precip largely ends at all sites by 12z though northerly upslope flow behind the departing system and lingering moisture should keep IFR or lower cigs/vis and areas of fog around through day break.

MARINE

Issued at 352 PM EDT Mon Oct 12 2026

Lake Superior: Occasional and low-end gale-force gusts have been realized throughout the day today in Lake Superior's western arm, while sustained winds have been mostly 25-30 knots. Over the central and eastern lake, elevated winds have stayed below gale force but generally are have been blowing a strong breeze, with occasional near gale gusts. Gales in the west are anticipated to linger into the night as waves likewise remain near 10-11 feet (5-9 feet elsewhere). Winds diminish notably through the early morning hours tomorrow to 10 knots sustained with 20 kt gusts by midday as high pressure moves in. Correspondingly, waves subside throughout Tuesday, decreasing to less than 2 feet by Tuesday evening. Winds and waves go light into Wednesday. 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 have been generally light and easterly today at less than 10 knots sustained with gusts to no more than 15 knots. Winds will pick up out of the east this evening to 15 kt sustained with gusts to 20-25 kt; zones on Lake Michigan will feel these winds more with waves to 4 feet in the pre-dawn period (0-2 ft in the Bay of Green Bay). Winds lay down shortly after sunrise, then increase slightly in the afternoon and winds back to the northwest, with gusts to 15 knots seen Tuesday evening. Wind and waves go light early Wednesday as high pressure moves in, and calm on Thursday. Late week could see a period of elevated winds to 25-30 knots from Friday afternoon into the evening.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning until 11 PM EDT /10 PM CDT/ this evening for LSZ162.

Lake Michigan... None.