textproduct: Marquette

KEY MESSAGES

- Slight risk of strong to severe thunderstorms this evening across Upper Michigan. Primary hazards are large hail and damaging winds.

- Marginal risk of strong to severe storms Thursday afternoon and evening in the south and east.

- Cooler and generally more pleasant weather in store this weekend into next week.

DISCUSSION

Issued at 237 PM EDT Wed Jun 10 2026

Early afternoon GOES satellite imagery reveals a weak shortwave responsible for this morning's early round of marginal thunderstorms and light rain lifting through Upper Michigan. This initial batch of precip has since decayed across the s-central. The next round of precip and severe weather activity is beginning to take shape across the Midwest as of writing this discussion. A deep trough axis extends southeast across the Driftless region, lifting rich theta-e air along and head of a warm front. Here, convective initiation is taking place across SW WI. Further upstream, additional convection is firing off along and ahead of a cold front in far NW MN. Ascent within this triple point zone will bring thunderstorms into the UP late this afternoon and evening.

Latest WoFs runs suggest growing MUCAPE reaching between 1500-2500 j/kg across the interior west coupled with 0-6 km bulk shear 35-45 kts. Isolated storms able to take advantage of steep low to mid level lapse rates will be capable of producing severe hail, generally 1 to 1.5". In addition, PWATs climbing upwards of 1.75 to 2" (99th percentile to max of NAEFs) and model soundings highlighting deep-warm cloud depths >10k ft point towards a marginal flash flood threat as storms will be prolific rain makers. WoFs and CAM guidance suggest a broken line of storms lifting across the stateline unfavorable of training, though cant rule out some isolated heavy rain. For these reasons, SPC has maintained a level 2 of 5 Slight Risk for severe weather across our CWA and WPC maintains and level 1 of 4 Marginal Risk for flash flooding. Outdoor recreationists should continue to monitor the forecast and have a way to receive a warning. Otherwise, clearing of earlier convective debris has allowed temps to push into the upper 70s to low 80s outside of the adjacent lakeshores. Not thinking anywhere will reach 90 as previously advertised by the NBM, though upper 80s cannot be ruled out. Increased moisture (dewpoints already hitting 60s to near 70) will certainly make it feel like 90! Overnight fog development is possible given the abundance of moisture.

Expect another warm day on Thursday, albeit with drier air in place as the greatest moisture will have moved east out of the area by that point. However, we can still expect high temperatures in the 70s to mid 80s across most of the U.P., with the warmest parts then being in the interior east. As a cold front pushes into the area from the west on Thursday, expect a shortwave low riding along the front to kick-off more showers and thunderstorms across the U.P. late in the afternoon through the overnight hours. While there will be a lot of shear to work with as the shortwave passes through, there won't be all that much CAPE. Therefore, the severe thunderstorm risk is rather low, with the SPC only highlighting the south central and eastern U.P. under a Marginal Risk (5% or greater chance) for severe hail and winds. Also, depending on how much rainfall falls with the convection this evening and late Thursday, there may be a spot or two that sees some flooding come late Thursday; thus, the WPC has the central and east under a Marginal Risk for excessive rainfall for Thursday.

Expect cooler temperatures behind the cold front from this weekend into next week as cool, dry interior Canadian air moves overhead. While a shortwave followed by another cold front could bring additional showers and thunderstorms to the area Friday afternoon and Saturday, expect drier weather overall as a low pressure spins from northern Ontario towards the St. Lawrence Seaway. Behind this low, ridging builds into the area early next week.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 131 PM EDT Wed Jun 10 2026

While IWD and SAW are lifting to VFR for the remainder of the afternoon, IFR/LIFR lingers at CMX over the next couple of hours as onshore flow continues to keep in marine fog and low stratus over the Keweenaw. A more robust round of showers and storms looks to return to the TAF sites late this afternoon into this evening, first at IWD and then at CMX and SAW closer to 00Z. With +TSRA possible, highly erratic and damaging winds as well as large hail could be seen. In addition, sharp vis and cig reductions as well as localized LLWS could be seen in the potentially +RA. While the convection will weaken and dwindle as it travels east out of the vicinity of the terminals late tonight, we could see flying conditions down into IFR or worse behind it; marginal LLWS is also possible behind the storms too. Though VFR returns at IWD behind the storms, IFR restrictions linger at CMX and SAW the rest of the night.

MARINE

Issued at 237 PM EDT Wed Jun 10 2026

The primary marine hazard in the going forecast remains afternoon and evening showers and thunderstorms slated to progress from west to east tonight. Strong storms will be capable of producing severe winds (>50 kts) and hail up to 1". Latest guidance suggests activity beginning to ramp up between 3-5pm (EDT) across the western arm of the lake to west of the Keweenaw Peninsula. Convection then presses east of the Keweenaw into the central and and eastern lake between ~8pm to 12am EDT. As storms reach the eastern half of Lake Superior, their strength should become more limited.

Transient areas of fog are visible via afternoon satellite imagery and despite areas of clearing and improved visibility seen on area webcams, opted to extended the lake-wide marine dense fog advisory though Thursday morning. With additional rainfall and increasing surface moisture lifting into the far northern Great Lakes, fog will be easy to redevelop. However, with breezy S to Sw winds, fog may be shunted to the northern fringes of the lake.

Another round of showers/storms lift through Lake Superior late Thursday into Friday but should remain sub-severe. Breezy SW winds 20-30 kts will be common Friday as a sfc low lifts through Ontario.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Dense Fog Advisory until 8 AM EDT /7 AM CDT/ Thursday for LSZ162-240>251-263>267.

Lake Michigan... None.