textproduct: Marquette

KEY MESSAGES

- Above-normal highs today and Friday.

- Rain shower (60-90%) and thunderstorm (up to 50%) chances arrive Friday afternoon and evening, with localized heavy rainfall. There is a Marginal Risk (category 1 of 5) for severe storms Friday afternoon and early evening over the west half.

- Pleasant temperatures are in store this weekend through next week, with rain showers and storms returning from time to time.

DISCUSSION

Issued at 200 PM EDT Thu Aug 6 2026

As southwest to southerly flow continues the rest of today into tonight ahead of an incoming cold front, expect the sunny skies today to allow temperatures to bring highs into the upper 70s to mid 80s, with observing platforms already showing temperatures generally in the 70s to lower 80s (warmest in the downslopes by Lake Superior). With mostly clear skies continuing into the overnight hours, expect temperatures to drop down into the 50s across the interior areas, with fog potentially returning to the south central once again late tonight. Ahead of the cold front on Friday, expect a near repeat of today, with highs again in the 80s, warmest along the Lake Superior downslopes in the central and east. While on the warmer side, generally pleasant weather is expected the rest of today to Friday (at least before the cold front arrives); take some time to enjoy the outdoors or get some outdoor work done. However, come Friday, be sure to keep an eye on the forecast and sky as the cold front moving in could bring rain showers and thunderstorms, beginning in the west by no later than the afternoon hours.

Impactful weather returns to the U.P. on Friday as a cold front starts to push into the area. While 0-6 km bulk shear isn't all that impressive along the cold front (only around 30 kts), with models trending the cap weaker at around 850mb, convection could become sfc- based by the afternoon hours. Thus, we may see SBCAPE/MUCAPE at around 1200 to 1500 J/kg by the afternoon to early evening hours over the west half. In addition, with strong theta-e advection lined up well with cold frontogenesis in the lower to mid levels, thinking there will be robust mechanical lift along the front to produce strong updrafts to support linear convection Friday afternoon. This is generally supported by the varying CAMs; while there is still a range on the timing on when the front arrives (could be as early as the morning hours, but highly doubtful of it), the general model consensus is that showers and storms move in during the mid- afternoon hours (2-4 PM EDT). Thus, while generally not expected along the line, a strong thunderstorm or two could bring some marginally severe winds (i.e. up to 60 mph) to the sfc over the west half Friday afternoon into early evening; thus, the Marginal Risk (category 1 of 5) that SPC has over us. In addition to the potentially stronger winds via the convection, some heavy rainfall is expected given the robust lift along the front. With PWATs generally getting up to around 1.50 inches ahead of the cold front, some heavy rainfall in excess of 1 inch could be seen across some spots of Upper Michigan; as of the time of this writing, the REFS brings up to a 50% chance that over an inch of rainfall will be seen between Friday morning and Saturday morning, with the highest chances over the west and north central. Looking at the LPMM for the REFS, the expected rainfall ranges from a quarter inch to 2+ inches over the west and north central, with the Porkies seeing 4+ inches. Therefore, while not expected, there could some spots, especially in the west, where some ponding of water/flash flood could occur. Across the rest of the U.P., expect generally a tenth of an inch up to potentially a whole inch of liquid by Saturday morning.

Moving into the rest of the forecast period, expect generally pleasant temperatures with highs in the 70s as a somewhat more zonal to northwesterly flow sets up across the Upper Great Lakes. While some weak sfc ridging generally sets up across the area, some weak shortwaves from time to time look to bring additional showers and thunderstorms to the area this weekend through next week. With 850mb temperatures dropping to around 9 to 10C behind the cold front early on Saturday, we may see some lake effect clouds over the northwest wind belts early Saturday morning, before warming temperatures bring an end to the cloud cover. Looking at just the 0-6 km bulk shear and MUCAPE, there is a chance that we could see some stronger storms come Sunday, but confidence on this is very low at this time (<5% chance). In addition, with a shortwave low on Monday having trended further south and now bringing the wrap-around moisture over the U.P., we could see at least a wetting rainfall across the area then (the NBM shows a 10 to 60% chance for at least a quarter inch of rainfall on Monday). By around next Thursday, we could see some lake effect clouds return as strong CAA with 850mb temperatures down to 6C potentially drop across Lake Superior.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 158 PM EDT Thu Aug 6 2026

VFR conditions prevail at all sites through the TAF period. Winds are filling in from the SW, with the gustiest conditions expected at CMX; IWD and SAW may experience a slight lull in the overnight hours. Some patchy fog may develop at SAW early tomorrow morning, potentially bringing restrictions, but confidence is low given increasing winds and dry air in place. A cold front is expected to roll through west to east tomorrow afternoon beginning after 18Z at IWD and around 21Z at SAW, bringing with it precipitation and thunderstorm chances.

MARINE

Issued at 200 PM EDT Thu Aug 6 2026

Southwest winds of 20 to 30 knots, greatest along the North Shore and north of Isle Royale, dwindle late this afternoon into this evening before reinvigorating to southerly winds of 20 to 30 knots tonight over Lake Superior. Winds look to die down again to 20 knots or less as a cold front moves through on Friday. That being said, some strong and erratic winds greater than 34 knots could be seen with the convection along the cold front over at least the western half of the lake Friday afternoon and evening. Could see some westerly wind gusts of 20 to 25 knots across Lake Superior on Saturday before returning WAA drops winds back down to 20 knots or less again Saturday night, with some showers and storms being possible late Saturday night into Sunday morning. Generally quieter weather is expected for the rest of the first half of next week over Lake Superior.

Over northern Green Bay and northwestern Lake MI, generally quieter weather is expected until southerly winds of 20 to 25 knots return to the area Friday afternoon ahead of the cold front. By the evening hours, some showers and storms could be seen over this area, with winds dying down to 15 knots or less after midnight. Light winds of 15 knots or less continue over northern Green Bay and northwest Lake MI the rest of this weekend through early next week, although some showers and storms could once again move through the area early Sunday and again on Monday.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... None. Lake Michigan... None.