Marine Weather and Tide Forecast for Sobieski, WI

DISCUSSION
Issued at 216 PM CDT Fri Apr 25 2025

Rest of this afternoon through Sunday night:

Showers will gradually push out over the course of the day today as the shortwave and corresponding mid level moisture pushes out with much drier air nudging in. Clouds may linger into the evening with the upper trough pulling through with some moisture associated with it but precip should end by the late afternoon to early evening across the CWA Tonight higher pressure will be pushing in behind this system with large scale ridging will become the dominant upper level feature by Saturday morning.

This weekend looks likely to be dominated by large scale ridging and high pressure with dry conditions expected. The only slight change to that is the potential for some shower activity Sunday night as a low pressure system nudges in from the west. The upper levels keep the ridge in place with perhaps some weak shortwave activity embedded in the ridge. Clouds seem likely with this especially with 700mb level moistening up as well but the lower levels remain fairly dry. Latest models have trended drier Sunday night likely due to the drier low levels helping prevent much in the way of precip reach the ground. However, it should be noted that overnight storm chances would be possible with this as some instability slides into the western CWA with this system but any stronger storms would likely be further west into Minnesota with the better shear.

Monday through the end of the week.

Into Monday it continues to become increasingly likely that some shortwave activity aloft could bring some showers and storms during the day Monday. This may play a role in what might occur later in the day and especially into the evening but as the surface low pulls through WI, models indicate the potential for strong storms across parts of WI. Latest trends have actually sped things up Monday which actually increases the strong to severe storm potential across the area. The better severe potential is likely located further south and west but the southern portions of the CWA will definitely see risks for strong to severe storms as well Monday evening and night.
Instability will be at least 1000-1500 J/kg and according to models appears that it may remain surface based well into the evening. In addition deep layer shear looks likely to be in the 45-60 kt range certainly keeping things organized into the late evening hours, especially with the increasing LLJ into the evening.

The question remains around the timing of storms and how much instability we will still have and whether it will be surface based by the time it comes through. If the current trends continue the risks across the CWA will increase and include more of the CWA
Currently this remains a situation with all hazards being possible.
CWASP values have increased over the area around 0.8-0.9 across southern to central WI suggests the potential for strong storms with tornadoes being a hazard. The decreasing instability in models into the evening also suggests possibly less of a hail threat but with the main threat likely being wind depending on storm mode. Based on environment and timing we would expect a largely linear QLCS type event. Thus the risks are winds and QLCS tornadoes with only small hail possible, especially given mode and the decreasing instability into the evening. The uncertainties with timing and even the slightest of shifts can significantly alter our potential for strong to severe storms.

Into Tuesday the front will have come through, very likely preventing chances for stronger storms. Showers will be possible on the backside of the low but overall by the evening higher pressure will be pushing in behind this system with weak ridging overhead.
Models keep things dry Wednesday with actually fairly good agreement overall. Thursday looks like there will be potential for activity with a developing low overhead and a shortwave aloft. Behind that shortwave into Friday models start to diverge a bit, especially in the upper levels. While large scale ridging will likely be the dominant feature the shape and track of the ridge starts to change and will likely impact precip trends heading into the weekend.

AVIATION
for 06Z TAF Issuance Issued at 1055 PM CDT Fri Apr 25 2025

A mix of MVFR and VFR cigs prevailed across the forecast area late this evening, with remnant light rain/BR over ATW and OSH departing to the south. Ceilings should then improve to VFR from west to east overnight, with clouds already beginning to scatter out over the western TAF sites. Biggest question will be when clearing makes it to east-central Wisconsin; have thus opted to speed things up so that VFR conditions reach all the TAF sites by around 06 to 08Z. Otherwise, CAMs continue to hint that a cu deck with bases at around 4 to 5k ft may develop over northern/eastern Wisconsin Saturday afternoon.

Northerly winds have continued to subside through the evening, although isolated gusts between 20 and 25 knots will remain possible across east-central Wisconsin overnight. LLWS will continue to be a minor concern across the western sites for the first few hours of the TAF period (~06 to 12Z) due to 35 to 40 knot 850 mb winds.

KGRB/KATW...

MVFR cigs persisted over GRB and ATW late this evening.
Otherwise, conditions gradually improve overnight as cloud cover scatters out from west to east, with VFR conditions reaching GRB and ATW by around 08Z at the latest.

Northerly winds continue to subside overnight, although isolated gusts to 20 knots will remain possible through early Saturday morning.

Mostly clear skies with sustained winds under 10 knots are expected Saturday afternoon.

MARINE
Issued at 216 PM CDT Fri Apr 25 2025

North winds have been dampened somewhat by the rainfall but on the backside of the rain expect winds to pick back up a little as low pressure tracks through Lower Michigan. Sustained winds of 15 to 20 kt are expected, with gusts to 25 to 30 kts possible into the evening. Waves will increase to 3 to 5 ft on Lake Michigan, but a shorter northerly fetch on Green Bay should generally keep waves in the 2 to 4 ft range. A Small Craft Advisory is in effect through 10 AM CDT Saturday now with winds expected to linger a bit longer than originally expected.

GRB WATCHES/WARNINGS/ADVISORIES
None.