Marine Weather and Tide Forecast for Sturgeon Bay, WI

DISCUSSION
Issued at 323 PM CDT Sun Jun 15 2025

Short Term...Tonight and Monday

Weak mid-level convergence and isentropic ascent may spur on a few light showers across central WI this afternoon, however, the better forcing remains southwest of the region. Otherwise dry and mostly cloudy condition will continue through this evening across the region. Scattered showers may develop across portions of central and north-central WI overnight as surface winds veer around to the south and WAA increases.

Monday will feel much more like summer as south southwest winds in advance of a developing cyclone over the Northern Plains feed much warmer and more humid air into Wisconsin. Highs are forecast to reach the upper 70s to middle 80s with dew points in the middle to upper 60s. The increasing warmth and moisture along with weak lift may initiate isolated to scattered showers and thunderstorms late Monday morning and afternoon, however, with weak vertical shear and capping in place don't anticipate any of these initial storms becoming severe. The window for severe is between about 4pm and 10pm. Will need to monitor upstream trends Monday to get a better handle of when/if any stronger storms will reach the forecast area.

The risk for severe thunderstorms does increase during the late afternoon and evening as CAMs show an MCS developing over Minnesota and pushing east toward central and northern WI. The finer details with this system remain rather difficult to pin down as CAMs still show differences in the timing and location of the middle-level shortwave and surface cold front that will be the primary forcing for any stronger storms. Should an MCS make it to central/northern CAMs do show a reservoir of 1000-1500 J/kg SBCAPE and slightly elongated hodographs which support a marginally severe hail risk. Any bowing segments may also pose a severe wind risk.

The progressive nature of these storms should mitigate the flash flood risk to a large degree outside of any urban or low-laying areas, however, periods of heavy rain will be possible. PWATs are forecast to be near 1.5" which is around the 90th percentile for this time of year. Soundings also show a warm cloud layer of around 8kft which should yield effect warm rain processes.

Long Term...Monday Night Through Sunday

There is high confidence in an active weather setup across the Upper Midwest/western Great Lakes through the long term forecast, but specific details on exactly where rain/thunderstorms will develop and track each day is difficult to pin down until each day gets closer.

The current guidance suggested a convective system will develop west of the forecast area Monday afternoon, reaching north-central WI around or a little after 00Z/Tue. This system will initially enter an unstable environment with MUCAPES of 1000-1500 J/kg, suggesting some strong or severe storms may continue (hence the Marginal Risk, level 1/5 from the SPC) into the evening. However, as instability wanes, the severity of any storms is likely to decrease, but exactly where and when that occurs is still uncertain. Current models would suggest west of the Fox Valley.

There will likely be a lull for the rest of Tuesday, with another complex developing Tuesday afternoon/evening, but this one is more likely to remain south of the area closer to where the surface front will reside, keeping the heaviest of the precipitation farther south. There remains high uncertainty Wednesday into Thursday with an overall messy weather setup due to various embedded shortwaves and surface fronts. The development of storms of a storm complex each day will depend on what boundaries and debris is leftover from the day before, and how this interacts with any upper level features. Rain and thunderstorms are throughout most forecast blocks, but it will not be raining or storming continuously. And there is potential both days end up mostly dry.

Upper flow amplifies near the end of the week, bringing northeast WI under the RRQ of an upper jet as a more defined front moves across Wisconsin sometime late Friday/early Saturday. This will be another opportunity for rain and thunderstorms, possibly strong to severe.

Meanwhile, temperatures will trend above normal through the period, with daily highs anywhere from the mid 70s to upper 80s, and daily lows anywhere from the low 50s to low 70s, warmest towards next weekend.

AVIATION
for 00Z TAF Issuance Issued at 633 PM CDT Sun Jun 15 2025

Mainly dry conditions were observed across the forecast area early this evening, with the exception of a few sprinkles over far NE WI. VFR conditions prevailed over the southeast half of the forecast area, with MVFR observed northwest.

Expect VFR conditions to prevail at the eastern TAF sites through the TAF period. MVFR conditions remain likely at the western TAF sites, but improvement to VFR seems plausible after a warm front moves through in the late morning/early afternoon on Monday.
Regarding precipitation chances, think there is a good chance of showers and possibly a few thunderstorms in C/NC WI as the remnants of upstream convection and an MCV (in western MN) move through Monday morning. There is less confidence farther east, so have only added a Prob30 for showers at the eastern sites during the late morning/early afternoon. This may need to be reassessed, as the air mass will be starting to get unstable in eastern WI when these showers arrive. A greater threat is expected in NC/C WI Monday evening, as a thunderstorm complex arrives. Will take a closer look at timing and impacts for the next set of TAFs.

Light easterly winds will gradually turn southeast overnight, then become a bit gusty from the south after the warm front moves through on Monday.

GRB WATCHES/WARNINGS/ADVISORIES
None.