Marine Weather and Tide Forecast for Sister Bay, WI

DISCUSSION
Issued at 346 AM CST Mon Nov 10 2025

Lake effect snow remains the main focus for one more day.

Center of anomalously deep/cold upper low is over southern Lake Michigan, spurring on intense lake bands into far southeast WI into the Chicagoland area this morning. Though farther removed from this activity, setup is still very favorable for locally vigorous lake effect bands into northern Lake Michigan and still up into central Upper Michigan and Lake Superior as well.
Soundings into northern Lake Michigan indicate that lake EQLs over 15kft don't cease until later this evening, so we'll still be dealing with the lake effect in Door County.

Early this morning, decent convergence band set up with radar algorithm pointing to snowfall rates up to 1"/hr. In the last hour as 925-850mb winds veered more northerly, the band has shifted to the east of Door County and weakened. Similar to yesterday though, though not as strong intensity, do expect snow bands to reform through the morning especially over northern Door County as plumes of lake effect and moisture off Lake Superior translate across the bay and Door County, enhancing snow showers. Manually bumped up QPF/snow, with a hint from max HRRR members (as nothing else showed it, nor did they yesterday either). A few more inches could occur through the day, with locally higher amounts possible far northern Door, toward Washington Island. Seems a good "floor" for additional snow amounts in northern Door into this afternoon is around 2 inches. Winter Weather Advisory issued until 6 PM tonight.

Winds shifting northwest will bring light lake effect into Vilas County as this event thus far has hit areas farther west and farther north. However, lowering inversions and less lift/moisture in the DGZ will limit additional snowfall to maybe up to 1 inch.
No plans to extend Winter Weather Advisory past 6 AM this morning for Vilas County. Otherwise, another cool day expected with highs mainly in the 30s and a few flurries at times in general NW to N flow across the area. A lull this evening, then as winds aloft back southwest, warm air advection aloft kicks in. Soundings show saturation aloft west to east after midnight. Some dry air in lowest 5kft. Envision some flurries or maybe a light dusting of snow working across the area. Some of this light snow may still be around for the morning commute on Tuesday over eastern WI, including the Fox Valley. Even with that timing, light nature of the snow in terms of accumulation and visibility, don't foresee much in the way of impacts. Any light snow exits by mid morning, allowing highs to reach upper 30s to lower 40s. Southwest winds could be gusty over eastern WI, though more significant gusts over 30 mph appear unlikely.

Rest of the week into the weekend...Light lake effect snow, maybe even mixed with drizzle at times owing to marginally cold airmass by that time occurs Tuesday night into Wednesday far north- central. Bulk of this light lake effect will be over Upper Michigan with NW wind direction. Warming trend continues overall with highs back into lower 50s by Thu/Fri and even mid 50s possible on Saturday. These warmer temps are ahead of a stronger northern stream shortwave trough and sfc low. Eventually some rain and wind could arrive over the region later in the weekend as this system moves through. NBM/LREF in agreement that probabilities highest for rain are Saturday night into Sunday. Both these forecast systems also suggest rain amounts of 0.25-0.25 inch could be in store.

AVIATION
for 06Z TAF Issuance Issued at 1041 PM CST Sun Nov 9 2025

Except for some MVFR CIGS and VSBYs across the far north overnight into Monday morning, VFR conditions will prevail through Monday evening. Winds have diminished during the evening and should continue to diminish towards daybreak on Monday. Gusty northwest winds will return by 15-16z Monday and continue through the afternoon, with gusts of 20-25 knots from the northwest are expected.

GRB WATCHES/WARNINGS/ADVISORIES
Winter Weather Advisory until 6 AM CST early this morning for WIZ005.

Winter Weather Advisory until 6 PM CST this evening for WIZ022.