textproduct: Marquette

KEY MESSAGES

- A cold front brings showers and thunderstorms to the area this afternoon and evening, with localized heavy rainfall. There is a Slight Risk (category 2 of 5) for severe storms over the western half of the UP with the main threats being gusty winds and large hail.

- After warmer conditions today, pleasant temperatures are in store this weekend through next week with rain showers and storms returning from time to time.

DISCUSSION

Issued at 219 PM EDT Fri Aug 7 2026

Afternoon GOES WV imagery shows a broad mid level troughing pattern over central Canada into the Upper Midwest, extending from a broad closed low spinning over Hudson Bay and northern Manitoba/Ontario. Embedded in this broad trough, a shortwave is moving over northern MN. At the sfc, a cold front and weak troughing drape southwest across MN. Visible satellite has shown ample clearing much of the day ahead of this front, allowing for plenty of warming in the mid 70s to low 80s. Tds in the mid to upper 60s have helped increase instability with SBCAPE upwards of 1500 J/kg with little to no CIN noted in the latest SPC mesoanalysis. As this boundary progresses eastward over the UP, shower and storm activity is expected to increase over the west late this afternoon, moving eastward through early tonight. CAMs are struggling with the onset of convection in the CWA. Given the lack of activity currently over the northern end of the cold front, a HRRR solution of slightly later timeframe than previously forecast is favored. Likely starting between 4-6 pm eastern in the west. 0-6 km bulk shear remains unimpressive, but sufficient at 30 kts for organized convection. Steeper low level lapse rates of at least 7.5 C/km alongside the favored linear mode support the main threat being gusty winds, however marginal mid level lapse rates and MUCAPE anticipated to reach 2000 J/kg leave a secondary threat of large hail on the table. Moisture is also not impressive, PWATs currently noted between 1.1 to 1.3 inches, but southwest moisture advection ahead of the boundary is expected to increase this to 1.4 to 1.8 inches (highest east into tonight). Probabilities of greater than 1 inch are between 10-40%, highest over the central UP. Totals are expected between 0.25 and 0.75 inches, save for the south central where coverage is lower and duration is shorter leading to lower amounts around 0.1 inch. These threats are captured well in the WPC marginal risk of excessive rainfall UP wide as well as the SPC slight risk for the west half of the UP and marginal risk for the remainder of the CWA.

Temperatures tonight range from the upper 40s to low 60s, coldest interior west in the wake of the front. Lingering shower and storm activity is expected to end in the CWA by around sunrise on Saturday. High pressure ridging at the sfc yields a dry and pleasant day on Saturday with mostly sunny skies and temps peaking in the 70s to low 80s.

Sunday brings back chances for showers and storms as a cold front moves through. Modest instability and plenty of bulk shear could support stronger storms, however better instability and forcing for severe storms remains south of the CWA. NBM probabilities of exceeding 0.25 inches of rainfall are between 10-40%, highest over the west half of the UP. Otherwise quasi zonal flow over the Upper Great Lakes leads to pleasant summer temps in the 70s the remainder of the forecast period with lows in the upper 40s to 50s. Chances for showers and storms dot the extended forecast as transient shortwaves traverse the area.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 725 PM EDT Fri Aug 7 2026

A cold front is bringing SHRA and TS to the UP this evening, bringing VFR to MVFR conditions (with IWD temporarily seeing a brief period of IFR as heavier showers pushed through around 22Z). Chances of overnight fog formation is low, but cannot be entirely ruled out with the lingering low level moisture post-storms (15-25% chance). Once the precip clears out, expect mostly benign VFR weather with winds out of the west (some SW and some NW variance) at 5-10 kt with 10-15 kt gusts.

MARINE

Issued at 306 PM EDT Fri Aug 7 2026

Winds across Lake Superior have generally fallen below 20 kts from this mornings uptick. That said, a few hours late this afternoon in the eastern lakeshores could see gusts reach into the low 20 kt range. As a cold front marches eastward over the area, southerly winds veer westerly. Shower and storm activity is expected to increase along this front late this afternoon, continuing into tonight before dry weather returns on Saturday. Some storms could be strong to severe bringing gusty winds up to 34 kts and hail. Fog development in the wake of precip is possible, but development will depend on shower coverage tonight and drier air following the front will be a limiting factor. This leaves low confidence in fog tonight into Saturday. Westerly winds generally remain below 20 kts on Saturday with high pressure building in, but channeling near Granite island and Isle Royale will yield some gusts to around 25 kts. Generally quieter weather is expected the remainder of the forecast.

On Lake Michigan, southerly winds are expected to increase to 15-25 kts for late this afternoon and evening ahead of a cold front. Satellite and available webcameras indicate dense fog along the lakeside nearshore zones. Hoisted a short fused Dense Fog Advisory into this evening. Sowers and storms are possible this evening into tonight, then winds die down behind the cold front, becoming northwest for Saturday. An isolated strong to severe storm with gusty winds cant be ruled out. Additional storms are possible on Sunday. Otherwise generally benign weather and light winds below 20 kts are expected the remainder of the forecast.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... None. Lake Michigan... Dense Fog Advisory until 8 PM EDT this evening for LMZ248.