Marine Weather and Tide Forecast for Mount Pleasant, WI

UPDATE
Issued 630 PM CDT Mon Sep 21 2026

Persisting east-northeasterly flow seems to be adding extra moisture (PWATs +1 inch) to the environment supporting the more robust shower activity across our western CWA with the mid- level shortwave trough. Have increased PoPs through the evening as obs have observed anywhere from a few hundredths to just under a two tenths of an inch. Do think this will weaken as it pushes east, but may be enough to support light showers/drizzles to the lakeshore. Otherwise additional light shower chances will be possible again overnight into early Tuesday morning for southwestern WI and along the WI/IL border as the upper wave continues to slide east.

Wagner

SHORT TERM
Issued 1254 PM CDT Mon Sep 21 2026

Tonight through Tuesday night:

Latest guidance continues to show shower chances this evening into early Tuesday as a weakening shortwave moves through.
Soundings show plenty mid and upper level moisture, so how much rain makes it to the ground will depend on how much the low levels saturate. Overall, the lower levels are looking more saturated per latest models compared to 24 hours ago. Based on this and upstream radar, have bumped up the precip chances roughly from Madison to Janesville and westward. Farther east, the lower levels will likely remain drier due to the influence of strong surface high pressure centered near the Ontario/Quebec border. Thus kept the forecast dry in the east/northeast, though a few sprinkles are possible. Temps tomorrow will be several degrees below normal again given the cooler airmass in place and expected mostly cloudy skies much of the day as the wave slowly exits.

The Beach Hazards Statement remains in effect until 7 PM CDT Wednesday evening for all Lake Michigan beaches, with persistent gusty east northeast winds and high waves of 4 to 8 feet. Stay out of the water, and away from dangerous areas like piers and breakwalls.

DDV

LONG TERM
Issued 1254 PM CDT Mon Sep 21 2026

Wednesday through Monday:

Strong high pressure centered just north of the eastern Great Lakes early Wednesday will largely remain in place the second half of the week while gradually weakening. Meanwhile, upper level ridging will attempt to build in from the west through late week. Models still differ as to whether southern Wisconsin will be more under the influence of the departing troughing pattern or the approaching ridge by the end of the week into the weekend. Thus there remains some uncertainty with temps during this period, though an overall slight warming trend looks likely. Additionally, models suggest a shortwave may come over the top of the ridge late week or during the weekend, bringing shower chances back to the area. As with temps, there is still uncertainty with the timing of any precip given the differences with the trough/ridge among models.

DDV

AVIATION
Issued 630 PM CDT Mon Sep 21 2026

Seeing more robust shower activity around MSN and JVL, and there may be a few pockets of lower ceilings and visibility with any moderate rainfall. However, VFR ceilings and visibility prevail across much of the area. Some decaying showers and drizzle may make it into the eastern terminals, but generally expecting this activity to gradually diminish after sunset. Otherwise, could see some additional light shower chances toward the WI/IL border overnight into early Tuesday morning, but then drier and VFR conditions are expected for the day Tuesday. With high pressure sitting to our northeast, expect breezy east to northeasterly winds to continue and becoming gusty through Tuesday afternoon before weakening by Tuesday evening.

Wagner

MARINE
Issued 1254 PM CDT Mon Sep 21 2026

High pressure around 30.4 inches north of Lake Superior today will shift eastward into Quebec tonight. The high will then largely remain in place through the middle of the week, while strengthening to around 30.7 inches by Wednesday morning. Gusty east to northeast winds are expected today through Wednesday.
Winds then look to diminish toward the end of the week, as the high pressure system slowly weakens and moves farther east.

DDV

MKX WATCHES/WARNINGS/ADVISORIES
WI
Beach Hazards Statement
WIZ052-WIZ060-WIZ066-WIZ071-WIZ072 until 7 PM Wednesday.

LM
Small Craft Advisory
LMZ643-LMZ644-LMZ645-LMZ646 until 7 PM Wednesday.