textproduct: Marquette

KEY MESSAGES

- Showers (and the occasional thunderstorm) continue over the east half the rest of today.

- Temperatures trend hotter today into Thursday, with widespread 80s seen Wednesday. Temperatures approach 90 in the far west on Wednesday.

- Strong to severe thunderstorms are becoming more likely late Wednesday.

DISCUSSION

Issued at 218 AM EDT Tue Jun 9 2026

As a shortwave low rotates through the Upper Great Lakes today, expect the rain showers (and occasional thunderstorm) currently over the western U.P. early this morning to continue eastwards throughout the rest of the day. With warm cloud processes continuing overhead, no severe weather is expected today with this shortwave. That being said, we could see some of the convection overachieve and bring up to an inch or more of liquid to isolated spots today over the Yoop. Otherwise, expect most areas of the central and eastern U.P. to receive just up to a few tenths of an inch of rainfall today. Therefore, while we are still technically within a Marginal Risk for excessive rainfall today over the eastern half, given the dry May we had and the flatter terrain over the east half, thinking no flooding concerns will be realized today.

Expect the warming trend to continue today into the next couple of days as Gulf air continues to be funneled into the U.P. thanks to stout low pressure lifting from the Northern Plains into the Canadian Prairies. The warm, moist air of the Gulf is expected to bring high temperatures into the 80s by Wednesday and Thursday, with some spots potentially flirting with 90 degrees in the west half. With dewpoints rising into the 60s today and Wednesday, we could see the Heat Index rise close to 90 degrees in at least the west half; the warmest and most moist day looks to be on Wednesday as of right now. While thankfully it looks like we will avoid Heat Advisory criteria, Yoopers should take care to limit our time outside and take frequent water breaks throughout the day as this may feel like one of the hottest days of the summer thus far.

In addition to the heat, more showers and thunderstorms are projected to impact the U.P. late Wednesday and again on Thursday as a cold front and shortwave low move into the region. With PWATs projected to be above the 99th percentile by Wednesday evening (over 1.75 inches), MUCAPE generally being around 1 to 2 kJ/kg, and 0-6 km shear potentially getting up to 50+ kts, severe weather is certainly on the table for at the very least the western half of the U.P. if not the entire peninsula Wednesday evening. As of the time of this writing, SPC has us under a Slight Risk for severe weather on Wednesday and Wednesday night (15% or greater chance), with the area along the Wisconsin border potentially seeing stronger hail and/or winds than everywhere else. In addition, because of the anomalously high PWATs and warm rain processes up to around 13 kft still, there still remains a Marginal Risk for excessive rainfall during this same time period. While flash flooding isn't expected given the dry May we had, given the rockier terrain over the western half and the potential for isolated cells to overachieve and dump potentially more than an inch or two of rainfall in a short amount of time, the threat is non-zero. While there may be a break in the precipitation early Thursday morning, expect a shortwave riding the cold front pushing through the region to bring additional showers and thunderstorms late Thursday through Thursday night; while the risk still remains low, there is a non-zero chance for severe weather and flash flooding/flooding Thursday evening with the passage of the shortwave given the recent rainfall late Wednesday.

Expect cooler/more normal temperatures come late this week through this weekend as continental Canadian air moves over the area. While this should limit highs to the 60s and 70s, expect lows to drop into the 40s and 50s during the overnight hours. In addition, the cool, dry airmass should overall reduce rainfall chances late this week into early next week. That being said, there may be a shortwave or two that brings some light precipitation back across the area from time to time over the last half of the forecast period.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 142 AM EDT Tue Jun 9 2026

Low pressure moving through the region will bring showers to the area through this morning. VFR conditions will fall to MVFR and IFR with the combination of very moist low levels, showers and light winds. Couldn't rule out periods of LIFR under the heavier showers. Conditions slowly improve at CMX and IWD this morning but showers will linger into the early afternoon at SAW. Tonight fog is expected to form at CMX and SAW, thus expect IFR and LIFR conditions late tonight.

MARINE

Issued at 218 AM EDT Tue Jun 9 2026

Light winds of 20 knots or less continue across Lake Superior the rest of today through tonight as a shortwave moving through the Upper Great Lakes today brings rain showers (and maybe an occasional thunderstorm or two) over mainly the central and eastern lake. Behind the rainfall, expect some marine fog, with some already being seen in the Duluth harbor early this morning (as seen via webcam imagery). Therefore, expect to see the Marine Dense Fog Advisories to continue expanding eastward throughout the day as the added moisture from the rainfall, the stout stable layer above the cool sfc waters, and the light winds are conducive to lake fog forming.

Winds begin to increase from the E/SE during the day on Wednesday to 20 to 25 knots as a cold front approaches from the Northern Plains. In addition, expect showers and thunderstorms to move into western Lake Superior by late in the afternoon; some of the storms could be strong to severe. As the front passes, expect the winds to become SW to W'rly to 20 to 25 knots Wednesday night into Thursday, with winds potentially gusting up to 30 knots between Thunder Bay and Isle Royale by Thursday afternoon. A shortwave riding the cold front could bring additional showers and thunderstorms back across mainly the central and eastern lake late Thursday before leaving by Friday morning; expect W winds of 20 to 30 knots behind this shortwave thanks to incoming CAA from the Canadian interior Thursday night into Friday. W'rly winds of 20 to 25 knots could continue even into Saturday as CAA continues, before finally dropping to 20 knots or less by Saturday night and Sunday.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Dense Fog Advisory until 2 PM EDT /1 PM CDT/ this afternoon for LSZ162-240>248-263>265.

Lake Michigan... None.