textproduct: Marquette

KEY MESSAGES

- Elevated fire weather conditions this afternoon across much of Upper Michigan due to relative humidity values around 20%, warm temperatures, and wind gusts of 15-20 mph.

- Scattered showers and thunderstorms return on Thursday, with another round likely Friday afternoon and evening. Uncertainty remains regarding precise timing and rainfall amounts in storms. Additional chances for showers and thunderstorms linger into Saturday.

DISCUSSION

Issued at 255 PM EDT Wed Jun 3 2026

Afternoon GOES-East Day Cloud Phase RGB imagery shows scattered cirrus and some fair weather cu along the spine of the Keweenaw but otherwise clear skies over Upper Michigan and the surrounding area. RAP analysis shows expansive high pressure near 1026 mb spanning much of the eastern CONUS with a near-stationary ~1015mb low over southern Saskatchewan extending a cold front and unsettled weather to its south. Aloft, the omega block is breaking sown, with a closed low over southern Saskatchewan and another over the North Carolina Coast with the ridge between them flattening over time.

RHs across much of the UP have already fallen into the 20s percents. Thus far, the highest recorded gusts coincident with these dry RHs are around 19 mph with most sites at 10 mph or less, limiting the wildfire spread potential. Little change in the wind pattern is expected today, with the CAMs showing the lake breeze remaining very close to shore along Lake Superior. Clear skies and warm southerly flow will lead to temperatures climbing into the upper 70s to mid 80s today, with the coolest spots being downstream of Lake Michigan.

Tonight into Thursday morning, with the ridge breaking down aloft, the stacked low over the Canadian Prairie will be able to move east and intensify to near 1008 mb over northwest Ontario by 12Z Thurs. This will bring cold frontal showers to the western UP around that time. Euro ensemble mean MUCAPE grows to 500-1000 J/kg throughout the day Thursday, giving fuel for showers to have some thunderstorm development, with 0-3km SRH values of around 125 to give some ability for the updrafts to organize and sustain. However, CAMs show significant placement and intensity differences for Thursday, so the threat remains similar to the SPC Outlook - Marginal. Those looking for a relief from the dry weather are not guaranteed a wetting rain, as chances of 0.1" of rainfall on Thursday are only sporadically above 40% and almost entirely west of the US-41/141/2 corridor (Crystal Falls, L'Anse/Baraga, Houghton/Hancock).

The low will only make slow progress eastward along the northern shore of Lake Superior through Friday, keeping rain shower and thunderstorm chances in the forecast. The best chances for thunder will be in the interior west to southern UP, especially east of the US-41/141/2 corridor where it is less likely that the previous day's storms will have worked over the atmosphere. LREF mean SBCAPE grows to around 500 J/kg with little to no CIN with 20-30 kt of deep layer shear. Another SPC Marginal Risk day appears warranted. One big difference in the forecast on Friday is the precipitation potential, as some training signal in the showers is seen. LREF chances of over a quarter inch of rain on Friday ranges from around 25% in the north to 75% in the south, which will be a welcome reprieve from the dry soils and vegetation.

Saturday morning, showers and thunderstorms depart to the east, with the exception of up to 30% chances (NBM) of the south seeing some diurnal afternoon showers/thunder in the afternoon. Ridging then sets up, leading to a dry Sunday. Models diverge on the details of the forecast into next week, but the general pattern is ridging over eastern North America and troughing over the west, setting up a warm and moist flow pattern that will allow NBM high temperatures to climb to the 90s in the west half and keep daily 15-30% shower and thunderstorm chances in the forecast.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 733 PM EDT Wed Jun 3 2026

VFR flight conditions likely prevail through the duration of the 0Z TAF period at all sites (70% chance). High pressure continues shifting southeast away from the Great Lakes, giving way to a weak low pressure system northwest of Lake Superior. This brings back chances for showers and storms on Thursday. Confidence in timing and coverage is low and forcing to begin with is weak, thus only -TSRA mention is via PROB30 groups at IWD/CMX. Similar chances arrive right at the end of the period at SAW, so mention altogether was left out. South to southeast winds between 5 to 10 kts tonight increase for Thursday to around 10 kts; a few gusts up to 20 kts are possible on Thursday.

MARINE

Issued at 255 PM EDT Wed Jun 3 2026

Winds will be mostly light throughout the period. Besides a brief period of wind gusts near 20 kt in the west in response to a LLJ, the next chances for widespread 20+ kt gusts will be Monday as the gradient tightens with various low pressure elements in the western US and a building high to the east of the lake.

MQT WATCHES/WARNINGS/ADVISORIES

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