Marine Weather and Tide Forecast for Fontana-on-Geneva Lake, WI

UPDATE
Issued 853 PM CDT Tue Apr 29 2025

High pressure will build into the region overnight, bringing light winds and mostly clear skies. Temperatures are expected to fall into the mid 30s, with a few pockets of low 30s possible over east central and central Wisconsin. Frost is expected in low lying and sheltered areas.

Boxell

SHORT TERM
Issued 440 PM CDT Tue Apr 29 2025

Tonight through Thursday:

Skies will continue to clear out going into tonight with winds turning light/calm as surface high pressure slides over the region. These efficient radiational cooling conditions will allow temperatures to fall into the mid-upper 30s across most of southern Wisconsin tonight, resulting in the development of frost across a good chunk of the area.

Tomorrow, a southern stream shortwave trough and associated surface low will lift northeastward towards the southern Great Lakes. Between a later arrival time of the better upper-level forcing support and the presence of very dry antecedent low to mid-level air, suspect that most, if not all, of the area should remain dry through at least mid-afternoon with many locations likely remaining dry through sunset. The bulk of the rain associated with the incoming shortwave should then arrive sometime tomorrow night as the tropospheric column saturates in tandem with the arrival of the better forcing for ascent. Mid- level lapse rates may just be steep enough to support a few rumbles of thunder within any convective elements embedded within the broader cloud and precipitation shield, but the overall greater potential for lightning should remain south of the Illinois-Wisconsin state line. Rain showers (with a continued low chance for isolated thunderstorms) should then stick around in some capacity through much of Thursday as the surface low pressure system tracks close by to our south.

High temperatures tomorrow should vary considerably from west to east with locations well inland likely to reach the low-mid 60s while onshore flow keeps locations closer to Lake Michigan mired in the 40s and 50s. Less variation in high temperatures is expected on Thursday, with highs then expected to top out somewhere between the low 50s and low 60s, depending on the extent of rain and cloud cover throughout the day.

Ogorek

LONG TERM
Issued 440 PM CDT Tue Apr 29 2025

Friday through Tuesday:

Heading into Friday, a few models do try to keep rain going, but there is less confidence here. POPs top out around 35 to 50% during the day Friday. Some guidance has an area of low pressure system or frontal boundary moving through the greater Midwest region. There is so much variation here and thus confidence is lower. The upper level trough should be overhead/exiting which will lead to less lift and pressure rises aloft. So overall not a great set up, but the chances still remain given these few members of guidance.

For the weekend, dry weather and high pressure look to prevail.
This will favor a warming trend heading into the weekend leading to some pleasant weather for the first weekend of May.

Patterson

AVIATION
Issued 853 PM CDT Tue Apr 29 2025

Calm conditions are expected overnight as high pressure moves through the area. Light and variable winds will become southeaterly on Wednesday, with mid level clouds building into the area by mid day. Ceilings will gradaully lower heading into to the late afternoon and evening hours on Wednesday, with showers and perhaps a few thunderstorms moving into the region from the south. Periods of showers and a few rumbles of thunder can be expected tomorrow night into Thursday, with ceilings eventually falling to IFR in many locations.

Boxell

MARINE
Issued 440 PM CDT Tue Apr 29 2025

Winds will turn northerly to northeasterly behind a lake- enhanced front through this evening before turning easterly tomorrow morning as high pressure of 30.2 inches departs the region. During the afternoon, winds are then expected to turn northeasterly over southern portions of the lake while becoming light from varying directions over the northern two-thirds of the lake.

Easterly winds will then redevelop tomorrow night as low pressure around 29.7 inches approaches from the Plains. That low will cross the southern tip of Lake Michigan Thursday morning, and winds will become northerly behind the associated cold front Thursday afternoon into the evening. High pressure of 30.1 inches will spread back into the region on Saturday.

WFO MKX/LOT

MKX WATCHES/WARNINGS/ADVISORIES
WI...None.
LM...None.