Marine Weather and Tide Forecast for Beloit, WI

SHORT TERM
Issued 1112 PM CDT Sat Sep 19 2026

Current Overnight through Sunday Night:

A band of moderate rain is currently angled from Northern Dane County through Northern Racine County in association with lift from 925mb frontogensis. Rainfall has been pretty efficient within this band, with 0.5 inch accumulations recorded within one hour. This band is generally pushing E-SE and should push out over Lake Michigan in a progressive manner over the next few hours.

Meanwhile, convection is currently blossoming south of the Wisconsin/Illinois border as WAA causes uplift over a sfc boundary. As the night goes on, high pressure from central Canada is expected build southward into the Upper Great Lakes, increasing the sfc pressure gradient and generating northeasterly flow, which will continue to keep the surface boundary south of the border. The compression of the environment between the high and the sfc boundary will also further intensify the convection over Illinois. It is projected that some of this convection will deal a glancing blow of rain to the southern Wisconsin Counties along the Wisconsin and Illinois border generally from 3am onward. While the heaviest rain will stay in Illinois, and additional inch to inch and a half of rain may occur during the early morning hours in these counties. A Flood Watch will stay out along the WI/IL border until 7am to account for the possibility of this rain overnight.

Rain should quickly end through the post dawn hours of the morning on Sunday as the influence of the high pressure continues to push into the upper Great Lakes region. By the mid to late afternoon, some breaks in the clouds may occur over east-central to south central Wisconsin. With the stronger pressure gradient over the region, wind gusts from 20 mph inland to 30mph near the lake will be possible.

The strong winds will drive high onshore waves and rip currents at all Lake Michigan beaches. A Beach Hazard Statement is in effect from now through Tuesday owing to the long duration hazards swimming conditions.

CMiller

LONG TERM
Issued 1148 PM CDT Sat Sep 19 2026

Monday through Friday:

High pressure will continue to linger over the northern Great Lakes Monday ahead of an approaching cutoff low over Iowa.
Chances for scattered rain (15 to 30% PoPs) will persist through the day as some moisture tries to work into the area from the cutoff low, but ultimately runs into the subsidence of the high. The cutoff low should lift back into the background zonal flow aloft Monday night into Tuesday and precip chances should largely end by Tuesday morning.

Dry conditions then look to be in store for the rest of the extended period. Some residual troughing aloft will keep us cool through the mid week period with highs in the low to mid 60s.
70s then return for the upcoming weekend as ridging begins to build over the upper MS Valley.

CMiller

AVIATION
Issued 1148 PM CDT Sat Sep 19 2026

A band of steady rain is currently located from roughly KMSN to KRAC. This band of steady rain will move east over Lake Michigan over the next few hours. Thunder is not expected with this activity. Convection over IL is then expected to deliver a glancing blow of rain from KEFT over to KENW through the early morning hours. Some thunder can't be ruled out with this activity.

The ample low- level moisture will promote vis and ceiling reductions into the LIFR to IFR category, with widely scattered VLIFR conditions. Winds will shift from easterly and light currently to northeasterly with gusts to 20 knots by daybreak Sunday.

Rain ends Sunday before noon, with ceilings gradually improving to MVFR by 18z with VFR then slowly working in from the north during the afternoon. Some breaks in the clouds may occur over east central to south central WI during the afternoon.

CMiller

MARINE
Issued 1142 PM CDT Sat Sep 19 2026

Low pressure over the central Plains will track to east central Illinois by Sunday morning, then settle over the southern Ohio Valley for next week. Meanwhile, high pressure over Manitoba will strengthen and track across Ontario for Sunday and Monday, then to Quebec for Tuesday and Wednesday. Modest east winds tonight will become breezy east to northeast winds Sunday through Wednesday with the highest winds over the south hal..
Winds may come within a few knots of gales Sunday afternoon and night over western portions of the lake.

CMiller

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

Flood Watch...WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-WIZ067-WIZ068- WIZ069-WIZ070-WIZ071-WIZ072 until 7 AM Sunday.

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