textproduct: Marquette

KEY MESSAGES

- Scattered showers and thunderstorms return, 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.

- A return to hotter and drier weather is favored as high pressure returns from Sunday into next week.

DISCUSSION

Issued at 254 PM EDT Thu Jun 4 2026

It's a tale of two halves of the Upper Michigan region on the afternoon GOES-East Day Cloud Phase RGB imagery. For the north and west, clouds with some embedded showers are advancing in, while the south and east are seeing clear skies. RAP analysis shows west- southwesterly flow aloft over the region as ridging over the Gulf is opposed by a closed low off the coast of the Carolinas and over Lake Winnipeg with the latter extending troughing over much of the Plains. This translates to a surface pattern consisting of expansive ~1022 mb high pressure over the southeast CONUS with a low of around 1008 mb over southern Manitoba that is extending a cold front across the Upper Midwest. 17Z KMQT radar returns show some pockets of showers, but METARs show significant Td depressions (approaching 40 F) that mean that whatever precip does form ahead of the cold front will have to fight a noteworthy surface dry layer.

This evening and tonight, HREF mean SBCAPE climbs to around 500 J/kg in the west, though with the front staying well to the west of the UP, forcing for showers is nebulous at best. HREF soundings at IWD show a veer/back/veer profile but without much speed shear in the lowest 300 mb, effective shear is minimal. Whatever showers do form may be initially robust enough to produce some thunder, but will not be organized enough to be particularly damaging. Not everyone will get a meaningful rainfall today, with chances of rain totals exceeding a tenth of an inch by Friday morning being only locally in excess of 30%.

The warm and moist south to southwest flow in the low to mid levels will result in PWATs climbing to 1.25-1.5 inches by 12Z Friday, around the 90th to 97.5th percentile of climatology per NAEFS. As the low pressure passes north of Lake Superior Friday, this moist air will be a key ingredient in redevelopment of showers and thunderstorms with diurnal heating support Friday PM. HREF mean SBCAPE climbs to around 1000 J/kg widespread across the UP with modest bulk shear around 25-30 kt though meager 0-3km SRH. CAMs indicate better chances at more widespread showers, though probabilities of robust enough updrafts to support severe weather is around 10%. This leaves the UP in a SPC Marginal Risk for primarily severe hail, though some severe wind near the state line is also a threat. The additional moisture available will help to provide a better rainfall for most, with widespread chances of over a quarter inch of rainfall in the 40-80% range (except for the Keweenaw), and some isolated pockets of 30% probability of an inch of rainfall indicating that some heavy downpours are also possible.

Most showers should exit the region by the overnight hours into Saturday, leaving a mostly dry day except for a few lingering showers early and a slight (~15%) chance of some redeveloping showers in the south central in the afternoon. With steep building 500mb ridging over the Great Lakes this weekend, expect a warming trend back into the mid 80s inland of the Great Lakes by Sunday, though weak surface flow under a surface high will keep lake breezes and cooler shoreline highs in the forecast. Beyond Sunday, ensembles struggle about the details, with various clusters of surface features, but the broad pattern of ridging centered over the Ontario/Quebec line and troughing over the West Coast will put the UP in southwesterly flow aloft with various shortwave features emerging from the base of the large-scale trough over the Rockies providing some opportunities for diurnally-boosted minor shower/thunder chances (~15-30%). The ridging and persistent warm southerly flow will keep the warming trend continuing, with the NBM suggesting some mid to upper 90s highs in the interior west in the mid- to late-week, though raw guidance suggests highs in the mid 80s instead, so it is to be determined whether the NBM bias correction is overcorrecting or if the hottest airmass of the season to date will be upon us.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 708 PM EDT Thu Jun 4 2026

Scattered showers and thunderstorms move across the terminals throughout the period as a low pressure continues to move across northern Ontario. The passage of the low may bring reduced cigs and vis into MVFR (and potentially even IFR at IWD and potentially even CMX) tonight. However, after the sun rises on Friday morning, expect conditions to improve to generally VFR across the area, although it's still possible that some showers and thunderstorms could drop conditions from time-to-time occasionally. Winds look to remain fairly SW/W tonight through Friday morning in association with the low's passage north of us. In addition, while not expected, some marginal LLWS could be seen for an hour or two, mainly at CMX where LLWS chances tonight are best.

MARINE

Issued at 254 PM EDT Thu Jun 4 2026

A low pressure passing north of Lake Superior to end the work week will bring up to 35% chances of some thunderstorms, but otherwise will not be strong enough to kick up wind gusts of 20+ kt. With high pressure reestablishing over the weekend, winds remain light until at least Monday, when some ensemble model solutions track a low pressure near the lake. This gives 50-70% chances of 20+ kt gusts especially in the east to central portions of the lake. Otherwise, the forecast next week looks either dominated by high pressure or the main surface pressure features remain far from the lake, keeping wind gusts and waves low.

MQT WATCHES/WARNINGS/ADVISORIES

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