textproduct: Marquette

KEY MESSAGES

- Above-normal highs today and Friday.

- Precipitation (30-80%) and thunderstorm (up to 30%) chances arrive Friday afternoon and evening, with localized heavier rainfall. Severe weather is not expected.

DISCUSSION

Issued at 307 AM EDT Thu Aug 6 2026

Early morning GOES water vapor imagery shows that the mid-level Canadian low has set up in conjunction with a Four Corners high, leading to SW'ly geostrophic flow over the region. An embedded shortwave is currently seen dropping over MN. A rather dry airmass in place will preclude any rain chances for today, with the only real impact being some stray cirrus overhead. Otherwise, expect increasing southerly winds today into tonight ahead of yet another shortwave that is set to impact the area Friday. Gusts up to 20mph will be possible especially over the higher terrain of the central and western UP beginning this afternoon. Temperatures, meanwhile, should come in higher than yesterday, peaking in the lower 80s for most while climbing higher into the mid 80s in the downsloping areas near Superior. Temperatures fall back only into the upper 50s to lower 60s for most of the UP tonight.

Friday's embedded shortwave and associated cold front bring notable precipitation and thunderstorm chances in the afternoon and evening. For moisture, ensembles feature anywhere from 1-1.5" of PWAT (or higher, per the Canadian). Latest NBM favors 6-hourly QPF of around 0.25-0.40" over the western half of the UP by 00Z Saturday, with lighter amounts to the east overnight as the front continues to make its way eastward. The NBM 90th percentile distributions remain around 0.50-0.75", and localized maximums sit upwards of 1". High PWATs, the trend in recent model runs, and high-end totals lend confidence to the possibility of localized higher rainfall during the afternoon and evening hours over the western UP. For severe potential, the ingredients are in place but largely lacking in magnitude. While good model agreement exists that the UP will be under RR entrance region of an upper level jet Friday afternoon, the speed of this jet is lackluster and positioning yields only speed shear. Ensembles and model soundings are converging on MUCAPE of up to 1000-1500 j/kg ahead of the front, though deep layer shear only peaks at around 30kts. Will note that most HREF members show some kind of linear structure developing Friday afternoon and sweeping across the area. Unsurprisingly, the western half of the UP has been placed under a Marginal for severe for Friday afternoon and evening, the main threat being wind gusts.

For the weekend, given the slow-moving Canadian low to the north, SW'ly mid-level flow veers to zonal. Subsequent shortwaves bring periods of some low chances of precipitation and thunderstorms Saturday through Monday, and temperatures should be close to seasonable. There are hints of a pattern shift by the middle of next week as the Canadian low slowly migrates eastward and ridging expands across the western half of the CONUS; this could support surface high pressure over the Great Lakes and another period of mainly dry weather in the Tuesday-Thursday period.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 1258 AM EDT Thu Aug 6 2026

VFR conditions prevail at all sites through the TAF period with around 10% chances of overnight FG development at SAW. Lighter, more variable winds overnight will increase to around 10 kt out of the south to southwest throughout today.

MARINE

Issued at 307 AM EDT Thu Aug 6 2026

For Lake Superior, winds are picking up out of the S-SW early this morning, with gusts up to around 15-20kts by daybreak. Higher gusts to 25kts will be possible between the Keweenaw and Isle Royale by mid morning. Southwest winds climb further tonight into Friday morning ahead of a cold front, with gusts up to 30kts possible. With frontal passage Friday afternoon/evening, rain and thunderstorms are likely and winds shift westerly while gusts decrease to 15 knots. Winds remain westerly Saturday, picking up to 15-20 knots through Saturday evening, then falling back to 15kts or lower Sunday. Waves build to 3.5 feet on the open lake on Thursday afternoon, then peak near 5 feet Friday morning before diminishing throughout the day. After this, waves remain below 2.5 feet through Sunday.

For the Bay of Green Bay and northern Lake Michigan, southerly flow will pick up to 15 knots for a brief period this evening. Friday evening ahead of the frontal passage, winds pick up to 20-25 knots for several hours, accompanied by rain and thunderstorm chances. After this, wind gusts fall back to around 10-15kts Saturday then decrease further Sunday. Waves are less than 1.5 feet the entire period, except for overnight on Friday when they approach 3 feet in northern Lake Michigan and 2 feet in the northern part of Bay of Green Bay.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... None. Lake Michigan... None.