textproduct: Marquette

KEY MESSAGES

- The warmest temperatures of the next week are expected today, with highs in the mid 80s to lower 90s.

- Showers and thunderstorms, with the potential for some to be strong to severe, are possible today and again on Monday.

- Generally quieter weather in store after Monday.

DISCUSSION

Issued at 228 AM EDT Sun Jul 26 2026

Mostly clear skies are overhead early this morning as local observations and satellite imagery hint at spotty fog trying to form, mainly in the interior areas. However, given the 'bust' in rainfall from yesterday, confidence in the fog forecast is somewhat low for this morning; while I'm sure some patches could become dense for a short while, given that the fog is not the primary concern for the forecast package, will leave the mentions of patchy fog in the forecast as is for now; although, if the fog overachieves, an update will be needed into the mid-morning hours.

Expect the warmest temperatures of the week today as highs soar into the 80s to lower 90s across the area, with the highest temperatures being seen in the interior west. With the anomalously warm air overhead, the U.P. is theoretically sitting on prime real-estate for severe weather potential today; convection could become sfc-based, provided there is enough forcing to overcome the small to modest capping at the 850-700mb level. In addition, MUCAPEs could jump to 1 to 3+ kJ/kg by this afternoon, with effective bulk shear in the ballpark of 40 to 60 knots. However, a large potential limiting factor is the forcing mechanism to get convection going. Recently, some of the CAMs, as well as the GFS, are keeping most of the convection either just south of the WI/U.P. border or calling for a precipitation bust altogether. Because of this, decided to lower the convection chances today and even moreso tonight. That being said, the latest (4z) run of the HRRR and RAP has shifted the convection that could develop this afternoon northwards into the U.P.. Should we have convection develop overhead today, there is certainly the threat for severe weather, with all threats on the table. However, the main threat would be for severe/damaging winds, followed by isolated cells producing large hail. Therefore, SPC has still kept most of the west and central under a Slight (>15%) Risk, whereas the east remains under a Marginal (>5%) Risk; the tornado risk is >2% over the west and central, whereas there is a 15% chance for considerable damaging winds and hail; as for the east, there is only a 5% chance for marginally damaging winds and hail as the convection would most likely not reach over there until the evening or later hours.

Another round of showers and storms potentially bringing severe weather with it is possible on Monday as a Clipper low moves through the Upper Great Lakes. Currently, severe winds are the primary threat, although large hail is a secondary threat as showers and storms associated with the low pass by. Again, looking at the latest CAMs, I'm not very confident on either the placement or timing of the convection; it is possible (at least a 50% chance in my own estimation) that the convection misses us entirely on Monday, most likely to the south of us (hitting WI instead). However, given the known issue of CAMs struggling to resolve the placement of individual cells, there is certainly still a non-zero chance severe weather could be seen in the U.P. come Monday as bulk shears still remain elevated at 40 to 55 knots and MUCAPEs could rebound up to around 2 kJ/kg near the WI border. Therefore, while I'm leaning towards Monday being a 'bust' for severe convection, I wouldn't rule it out just quite yet.

Behind the Clipper low on Monday, expect quieter weather across the region as geopotential heights rise over the central CONUS into Canada. With a semi-omega block appearance forming over the central CONUS, we could see a few weak Canadian shortwaves move across the area (mainly the first weekend of August). However, because recent medium-range runs are showing mid-level heights increasing locally over the Upper Midwest and Great Lakes for the middle of the week, thinking we will more likely than not remain dry until potentially next weekend.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 116 AM EDT Sun Jul 26 2026

VFR prevails for most of the forecast period. However, with winds becoming light tonight, patchy fog is already beginning to develop across the region. Fog becomes most likely at CMX and SAW, though some fog will also be possible at IWD. Fog may drop visibility to MVFR or lower; certainly not out of the realm of possibility for airport mins to come into play as we close in to 12z this morning. Expect winds to turn more westerly into the daytime hours today, with cloud cover increasing by the afternoon hours. There is potential for showers and thunderstorms today, which would lead to erratic winds and potential drops in ceilings and visibility; however, confidence in timing and coverage is still too low to include storms in the TAF at this time.

MARINE

Issued at 228 AM EDT Sun Jul 26 2026

Light winds of 20 knots or less dominate this week. That being said, some convection, potentially strong to severe, could be seen over mainly the western half of the lake this afternoon into early this evening, although confidence in this happening is low (less than 30% chance). Should strong to severe storms happen, the primary threat would be damaging winds, followed by large hail with a low-end chance for a tornadic waterspout. Some stronger convection could also appear across the lake on Monday as well, but confidence in this happening is even lower than today's (20-25% or less); damaging winds look to be the primary threat should it occur. Expect quieter weather from Tuesday onwards.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Dense Fog Advisory until 11 AM EDT /10 AM CDT/ this morning for LSZ162-263-264-266-267.

Lake Michigan... None.