textproduct: Marquette

KEY MESSAGES

- Scattered showers and thunderstorms expected today, a few of which could be strong in the afternoon. Rainfall amounts will range from a quarter to a half inch across much of the area through this evening. Additional chances for showers and thunderstorms linger tonight into Saturday morning.

- Hotter and drier weather is favored in the long term as high pressure returns next week.

DISCUSSION

Issued at 351 AM EDT Fri Jun 5 2026

Early morning water vapor imagery and RAP analysis show moist southwest flow in place across the Upper Great Lakes with a stacked low pressure system located upstream over northwest Ontario. A surface cold front extends south from this low across north-central Minnesota. Regional radar imagery shows one band of light rain showers moving across the eastern half of the U.P. while another stronger band of showers with some embedded thunderstorms moves over the western arm of Lake Superior supported by up to 500 J/kg MUCAPE per SPC mesoanalysis. This activity will push east into the U.P. through later this morning, providing around a tenth of an inch of rainfall to a few locations in the western half during the morning hours.

The warm and moist south to southwest flow in the low to mid levels of the atmosphere will maintain PWATs of 1.25-1.5 inches over the U.P. into this afternoon, around the 90th to 97.5th percentile of climatology per NAEFS. As the low pressure passes north of Lake Superior today, this moist air will be a key ingredient in redevelopment of showers and thunderstorms with diurnal heating support in the afternoon. HREF mean SBCAPE climbs above 1000 J/kg widespread across the UP with modest bulk shear around 25-30 kt though meager 0-3km SRH. CAMs continue to indicate better chances at more widespread showers, though probabilities of robust enough updrafts to support severe weather remain around 10%. This leaves the U.P. in a SPC Marginal Risk today for severe hail and wind gusts. 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. With 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 /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 745 AM EDT Fri Jun 5 2026

Mainly VFR across Upper MI this morning as one round of showers departs the eastern UP. Still some lingering lower clouds in the west which could cause some intermittent drops to MVFR at KIWD and KCMX through around 15z. Showers and thunderstorms fill back in as a front crosses the area this afternoon and instability increases with daytime heating. Expect -TSRA to remain sough of KCMX, ending at KIWD by around 00z Sat and KSAW by around 04z. Expect VFR conditions and light winds thereafter through the end of the TAF period.

MARINE

Issued at 351 AM EDT Fri Jun 5 2026

A low pressure passing north of Lake Superior today 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.