Marine Weather and Tide Forecast for Cedar Grove, WI

UPDATE
Issued 957 PM CDT Wed Apr 23 2025

Scattered showers and thunderstorms continue to develop and shift slowly east northeast from north central Iowa into areas west of Madison, aided by a modest low level jet nose and some 850 mb convergence/frontogenesis response.

CAMs that are handling the current activity decently try to bring scattered showers and storms into areas mainly west of Madison to perhaps north and northeast of Madison into the overnight hours. The convection should gradually weaken later tonight, as elevated CAPE weakens and the upward vertical motion fields weaken as well. Still could see hail up to one half inch west of Madison with the strongest storms.

Otherwise, some fog may develop across the area later tonight into early Thursday morning, as light winds and lingering higher dew points may allow for the fog. Middle to high clouds may limit this development.

Wood

SHORT TERM
Issued 305 PM CDT Wed Apr 23 2025

Tonight through Thursday night:

A period of descending motion following the departure of this morning's weak MCV has left a window for sunshine to gradually steepen the low-level lapse rates (which are currently poor, as evidenced by the general lack of fair wx cumulus clouds). A few isolated showers or even a weak storm may form in far southern WI (near the IL border) over the next few hours, but will be limited by the poor thermodynamics in the wake of this mornings convection. Instead, the main area we are watching is the cumulus field evident on satellite in northeast Iowa, any convective initiation that occurs in that region is likely to drift eastward later this afternoon into this evening, impacting our region after low level lapse rates have steepened in the sunshine. The current forecast for late this afternoon into this evening currently features 15-35% chances for thunderstorms (highest further west), though this could be increased if favorable timing / upwind-placement of initiation in Iowa / southwestern WI occurs.

If this scenario were to play out, we'd be working with an environment of 40-50kt effective wind shear (mostly aloft, shallow shear and helicity are relatively weak), with steep low and mid-level lapse rates. This would create some cellular or line-segment storms with a threat for gusty winds and hail, with a few strong to severe storms possible. There may be enough helicity aloft for a few storms to rotate (thus contributing to hail and wind being the main concerns), but low-level helicity integrals are not looking impressive. That, coupled with the development of the NBL later this evening will limit tornadic potential.

Showers/thunderstorms may linger into Thursday morning, followed by a lull in the activity mid-Thursday / Thursday afternoon. East to northeast winds through this time will hold daytime high temps to the 50s, but allow highs in the upper 60s to low 70s further west. Widespread showers with potential for some rumbles of thunder then expected late Thursday evening through Friday morning as a weak low pressure system crosses the region.

Sheppard

LONG TERM
Issued 344 PM CDT Wed Apr 23 2025

Friday through Wednesday:

The 12Z GEFS and 12Z ECMWF show fairly good agreement with the track of a wave of low pressure and shortwave trough aloft from srn IA to se Lower MI during the day on Fri. Widespread showers and isold thunderstorms will move across srn WI during this time. Nly winds and cold advection will then develop for the afternoon and night.

A large high pressure area will then shift across WI for Sat- Sat nt with 500 mb height rises ahead of the upper ridge over the Great Plains. A nice day with temps slightly below normal is forecast. The high will shift east for Sunday with lgt sly winds and warm advection beginning as the upper ridge nears.
High temps will rise into the upper 60s well away from Lake MI.

Breezy sly winds and warm, moist advection will then increase Sun nt- Mon as low pressure over the intermountain west moves into the nrn Great Plains and eventually nrn MN. There will likely be a round or two of showers and storms within a warm, humid airmass. Another round of showers and storms would likely occur Mon nt ahead of the approaching cold front that will pass on Tue, with less activity along the front on Tue. High pressure will then arrive for Wed.

Gehring

AVIATION
Issued 957 PM CDT Wed Apr 23 2025

Scattered showers and thunderstorms continue to develop and shift slowly east northeast from north central Iowa into areas west of Madison. They may spread into areas north to northeast of Madison overnight, gradually weakening. There could be small hail to one half inch with the strongest storms west of Madison.

Otherwise, some light fog with 2 to 5 mile visibility may develop across the area between 09Z and 14Z Thursday, with light winds and lingering moisture. Broken middle to high clouds may limit this development. There may be some low ceilings around 500 feet AGL that remain just east of the lakeshore terminals, along with 1 to 2 mile fog, during this period.

Winds will shift to the north by dawn Thursday morning and become northeast to east by middle morning, lingering into the afternoon and Thursday night. Broken middle to high clouds should linger Thursday into Thursday evening.

Small chances for showers may linger Thursday afternoon and evening, with better chances for showers and a few storms later Thursday night into Friday morning.

Wood

MARINE
Issued 957 PM CDT Wed Apr 23 2025

A weak cold front will work across the open waters of Lake Michigan overnight into Thursday morning, allowing winds to shift north to northeast. Some fog may develop over portions of the lake overnight into early Thursday morning as well. The north to northeast winds will continue through Thursday night, as high pressure around 30.4 inches builds into the northern Great Plains.

Low pressure around 29.9 inches will then move northeast across southern Lake Michigan on Friday morning, bringing gusty northerly winds behind it for Friday afternoon and night.

Gales appear unlikely at this time over the open waters, but Small Craft Advisory level winds and waves are possible Friday into Saturday morning for the nearshore waters. Breezy conditions will continue through Saturday, with winds tapering Saturday night, as strong high pressure around 30.5 inches builds in from the northern Great Plains.

Wood

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