Marine Weather and Tide Forecast for Racine, WI

UPDATE
Issued 922 AM CDT Sat Jun 21 2025

Forecast appears to be on track with temps and dew points hitting their early hourly marks. Expansive area of 70F+ dew points currently extends from northern Wisconsin down to the Gulf with the highest values being in the mid-upper 70s in eastern Illinois. Currently sitting between 72-75F in southern Wisconsin, which is where I think we'll be at much of the day as diurnal mixing should lead to these numbers maybe dropping off a degree or two as the 21.13z RAP showings boundary layer dew points staying at 72F or higher through mid afternoon. Winds will be gusty today and out of the southwest, which should keep the lake breeze at bay. With winds over Lake Michigan being out of the south, the lake breeze currently doesn't come on land until you get toward Manitowoc where the land mass starts jutting northeastward. This will create a dangerous swimming day on Lake Michigan for Ozaukee and Sheboygan counties due to the southerly winds and their orientation to the wind.

Otherwise, some high level cloud cover to start this morning due to blow off from the MCS in northern Wisconsin. Some low level moisture appears to be trapped just under the nose of the inversion as some cumulus has formed as mixing began this morning. Expect that this will clear out through the day and skies will be mostly sunny. No changes planned for the forecast/headlines today with things looking on track at the moment.

Halbach

SHORT TERM
Issued 423 AM CDT Sat Jun 21 2025

Today through Sunday:

A very strong upper level ridge arrives today and will continue to build over the Upper Great Lakes Region into tonight. Model depictions of the ridge show steady 500mb height rises into Sunday, indicating a very capped and warm air mass. A strong 925 to 850mb jet will also advect moisture from the central plains into our area, and dew points will rise to the low to mid 70s by this afternoon. Afternoon highs are anticipated to reach the mid 90s, and with the humidity, heat indices will rise to between 100 and 105 over most of southern WI prompting a Heat Advisory.

Milwaukee, Racine, and Kenosha Counties will experience the effects of downsloping off of the Kettle Moraine from strong southwesterly winds and will also experience the urban heat island effect in the metro areas. This will allow slightly higher air temperatures in the upper 90s this afternoon and heat indices between 105 and 110. An Extreme Heat Warning remains on track for these counties.

As mentioned, a strong 925-850mb jet will be aloft today, and daytime mixing will transfer this momentum to the surface.
Strong southwest winds are anticipated through today, with gusts between 25 to 35 mph. These strong winds will have more of a southerly component over the Lake, owing to a lack of friction there. As a result, high waves and shore parallel currents are expected to drive a High Swim Risk for Sheboygan and Ozaukee Counties, and a Moderate Swim Risk for Milwaukee, Racine, and Kenosha Counties. It is advised to stay out of the water and away from piers and breakwalls.

With the ridge continuing to build on Sunday, temperatures will be slightly hotter with temps potentially a degree or two above highs that occur today. Heat Advisory and Extreme Heat Warning conditions will continue through Sunday. The core of the LLJ will weaken aloft, but breezy southwest winds will continue on Sunday with gusts to 25 knots.

CMiller

LONG TERM
Issued 423 AM CDT Sat Jun 21 2025

Monday through Thursday:

Heat and humidity continue for Monday with temps in the 90s and heat indices around/exceeding 100F as the upper-level ridge axis shifts into the eastern Great Lakes. Meanwhile the shortwave trough trekking across the northern Plains is progged to lift into Canada through the day Monday. This will lift a surface low from the Dakotas up across the Upper Great Lakes region into Ontario Monday evening then dragging a cold front into our neck of the woods. Forcing along this boundary paired with ample moisture (PWATs in excess of 1.5 inches) and the highly unstable environment looks to be enough for convection to develop along and ahead through the evening. There also looks to enough deep layer shear for some stronger to even severe thunderstorms capable of producing hail and damaging winds. However, uncertainty remains on where the cold front boundary sets up given the variability on the models. Nevertheless, will need to monitor over the coming days.

This boundary will then be the focus for a potentially active period through the middle of next week as the upper-level pattern looks to turn zonal with the boundary stalling out somewhere across the area.
This pattern would favor multiple rounds of convection and potentially evening training type set up leading to flooding rain potential. However, long-range models continue to waffle this boundary back and forth, thus unable to pinpoint exactly where it will set up, but will need to keep an eye on how and where it sets up next week as it will bring another active period to southern WI.

Wagner

AVIATION
Issued 922 AM CDT Sat Jun 21 2025

Some low level moisture under the inversion at 5kft has allowed for few-sct 2kft cumulus to form across southern Wisconsin in response to some outflow that occurred earlier this morning from the storms in northern Wisconsin. A few spots briefly have gone BKN at 2500ft, but think that will be short lived as temperatures warm and mix out this moisture. Otherwise, winds will continue to be the main focus going through tomorrow. As winds decouple tonight, could see some low level wind shear again with a 45kt wind core sitting at about 2kft.

Halbach

MARINE
Issued 423 AM CDT Sat Jun 21 2025

Strong warm advection on south winds is expected to cause breezy conditions over the lake today. While momentum will be very strong a few hundred feet above the lake surface courtesy of a strong low level jet, a strong surface inversion caused by the colder lake waters will limit how well this momentum will transfer to the surface. Gusts between 25 to 32 knots will be prevalent and a few intermittent gusts to gale force can't be ruled out over the northern half of the open waters of Lake Michigan and nearshore areas late this morning and into the afternoon. A Small Craft Advisory is in effect into tonight.

Winds will weaken somewhat for Sunday but still remain breezy, as the core of the low level jet translates east and a new one forms over the central plains, leaving us in a zone of weaker flow. South gusts to 25 knots will be possible, with similar conditions on Monday. A Small Craft Advisory may be needed for Sunday into Monday as well.

CMiller

MKX WATCHES/WARNINGS/ADVISORIES
WI
Beach Hazards Statement
WIZ052-WIZ060 until 10 PM Saturday.

Heat Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057- WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ067- WIZ068-WIZ069-WIZ070 until 7 PM Monday.

LM
Small Craft Advisory
LMZ643 until 4 AM Sunday.

Small Craft Advisory...LMZ644-LMZ645-LMZ646 until 10 PM Saturday.