Marine Weather and Tide Forecast for Sister Bay, WI

DISCUSSION
Issued at 222 PM CDT Fri Jun 26 2026

Skies were partly to mostly cloudy this afternoon. Temperatures were in the middle 60s to lower 70s, which is several degrees below normal for late June. Tranquil conditions expected to continue through Saturday night as high pressure is in place. High temperatures on Saturday will be closer to normal with readings around 80 with tolerable humidity levels.

Late Saturday night, a warm front will approach Wisconsin from the southwest and then move across the state Sunday and Sunday night.
There are still many questions in how quick the convection will break as southerly low level winds increase during the afternoon and Sunday night. Bufkit soundings indicated 700/500mb lapse rates of 7.5-8.5 C/KG, CAPE values increasing to 1,000 to 2,000 J/KG and 0-6 km shear values of 30 knots would support strong to severe thunderstorms. The models are depicting scattered convection across northeast WI during this time frame. Most of the convection should exit the area late Sunday night or early on Monday morning. The current Day 3 Outlook from SPC has a Marginal Risk into Vilas and Oneida counties.

On Monday, it will be hot and humid as there will be capped as the convective temperatures for the afternoon will be close to 100F.
High temperatures in the 90s, combined with dewpoints in the lower to middle 70s will result in the heat index climbing to 100-105F.
We will be flirting Heat Warning Criteria (105F) for a few hours during the afternoon. Heat headlines are likely.

700mb temperatures peak at 15C on Monday which supports little chance any convection would get going. By Tuesday, the 500mb ridge is expected to be centered across the Ohio Valley with the western Great Lakes region in the ring of fire. Models continue to differ on timing/how far south into the ridge for convection moving across the area, with the GFS keeping most of the activity north of Wisconsin. This would result in several days of hot temps and heat index values reaching advisory or warning criteria.
Yesterday, Tuesday was a potentially a busy day with a complex of storms. The Canadian model has moved away from this solution while the ECMWF depicts a complex across the area Tuesday which would significantly impact high temperatures and maximum heat index values. For the rest of the week, there are periodic chances of thunderstorms. With all the heat and humidity in place, the potential exists for strong or severe storms at times. Timing and location of MCS complexes this far out is difficult at best.

AVIATION
for 00Z TAF Issuance Issued at 603 PM CDT Fri Jun 26 2026

VFR conditions should prevail through Saturday afternoon. The only exception may be for some patchy MVFR VSBY between 07z-13z overnight into Saturday morning due to light fog. Otherwise, east-southeast flow expected through Saturday afternoon. The next chance of storms will not be until late Sunday afternoon and Sunday night. Hot weather is expected at times next week with highs in the 90s across much of the area away from the bay and Lake Michigan.

GRB WATCHES/WARNINGS/ADVISORIES
None.