textproduct: Marquette

KEY MESSAGES

- Widespread moderate rain chances (30-60%) Saturday afternoon into Sunday, along with low thunderstorm chances (15-20%) during the overnight hours. Severe weather is not expected at this time.

- Some light lake effect rain showers could be seen over the western UP Sunday morning.

- High temperatures are expected to be in the mid-70s to low 80s into next week, with low temperatures generally in the 50s to low 60s.

DISCUSSION

Issued at 127 PM EDT Fri Aug 14 2026

Satellite imagery shows the U.P. under mostly sunny skies this afternoon as high pressure ridging continues to strengthen, with guidance suggesting it reaches its zenith at around 1023mb this evening over Lake Superior. Because of the high pressure ridge, highs get into the mid-70s near Lake Superior today while areas further inland and away from the lake get into the lower 80s. This is reinforced by the latest area observations, which show temperatures in the upper 60s to lower 70s along the Lake Superior shoreline whereas some spots in the interior are already reaching into the lower 80s.

With the high pressure retreating late tonight and three shortwave lows (one over the Dakotas and the other two currently over the Central Plains and Colorado Rockies) lifting ENE tonight through this weekend, expect cloud cover to increase by Saturday morning. However, with the shortwave over the Dakotas moving into northern Ontario and eventually Lake Superior this weekend while the other two southerly shortwaves ride along the warm and cold fronts, thinking rain chances and amounts will be lower than previously expected earlier this week, with the latest HREF showing most of the area having a 0% chance of receiving greater than a quarter inch of rainfall by Sunday morning; the exceptions are generally along Lake Superior where slight better forcing is, squeaking chances up to 10 to 50%. With the southerly shortwaves depriving us of Gulf moisture, convective potential is also significantly lower; currently thinking the NBM is correct to have thunder chances at around a 15 to 20% chance, although the thunderstorm chances may begin Saturday afternoon over the west and south central instead of during the evening hours. Nevertheless, feel like the NBM forecast is close enough for thunder chances, so decided to roll with them for the official forecast. As the northerly shortwave rolls towards James Bay on Sunday, temperatures aloft could be cold enough to create light lake effect rainfall over the western U.P., particularly during the morning hours behind the strongest cold air advection. However, as high pressure starts building back in late this weekend into early next week, expect the lake effect rain showers (should they occur) to be done by Sunday evening.

While the differing model suites diverge next week, warmer temperatures and drier weather is expected for Monday as shortwave ridging and warm air advection move into the area. Behind it, guidance does hint at either a shortwave or front moving through the area sometime around mid next week. However, details are still highly uncertain at this point, as the track of the shortwave could significantly alter the rainfall amounts and chances over us as the cold front moves through during the middle of next week. Nevertheless, the latest NBM has wetting rainfall (greater than a quarter inch) chances at around a 25 to 65% between Tuesday morning and Wednesday morning. More high pressure ridging could be seen once again over the area as we head towards the end of next week.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 116 PM EDT Fri Aug 14 2026

VFR conditions will prevail through the TAF period along with light winds. High pressure moving through the Upper Great Lakes will result in quiet weather with only some passing high-level cloudiness through tonight. Low pressure will move into southern WI on Saturday spreading mid-level moisture into the area with skies becoming BKN/OVC as the morning progresses, cigs will be 10kft or higher.

MARINE

Issued at 127 PM EDT Fri Aug 14 2026

Winds over far western Lake Superior increase up to 20 to 30 knots from the northeast before dwindling down to 20 knots or less again tonight. As high pressure ridging leaves the Upper Great Lakes tonight and generalized troughing approaches from the west tonight through this weekend, expect winds to pick up from the east to southeast to 20 to 25 knots over south central Lake Superior on Saturday; some gusts up to 20 knots will also be possible over northwest Lake Michigan as well during this time. Some showers and thunderstorms could be seen over western Lake Superior Saturday afternoon, moving over the rest of Lake Superior and over northwest Lake Michigan and northern Green Bay Saturday evening into Sunday. Thankfully, no severe weather is expected. With cold air advection being seen behind the showers and storms over the Upper Great Lakes, expect northwest winds to increase to 20 to 30 knots over mainly the eastern half of Lake Superior on Sunday; expect northwest gusts of 15 to 25 knots over northwestern Lake Michigan and northern Green Bay from Sunday afternoon until Sunday evening as well. On Monday, winds could increase from the southwest to 20 to 30 knots between Thunder Bay and Isle Royale as a cold front approaches behind a high pressure ridge. While the winds look to dwindle to 20 knots or less again by Monday night over Lake Superior, some southwest to northwesterly winds of 15 to 20 knots are possible over northwestern Lake Michigan and northern Green Bay via this cold front on Tuesday. In addition, some showers and thunderstorms could be seen over Lake Superior on Monday through Tuesday, and over northwestern Lake Michigan and northern Green Bay on Tuesday into potentially even Wednesday.

MQT WATCHES/WARNINGS/ADVISORIES

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