Washington Island, Wisconsin Weather Forecast Discussion

220
FXUS63 KGRB 111147
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
647 AM CDT Thu Sep 11 2025
Updated aviation portion for 12Z TAF issuance
.KEY MESSAGES...
- Areas of fog, locally dense, will impact travel across parts of
  the region early this morning, and again late tonight into early
  Friday. A Dense Fog Advisory is in effect for far northern WI
  through 9 am today.
- Chances for showers and thunderstorms return Friday night into
  Saturday morning, but severe weather is not expected.
- Above normal temperatures are expected from Friday through next
  Thursday, with rain chances increasing by the middle of next
  week.
&&
.DISCUSSION...
Issued at 337 AM CDT Thu Sep 11 2025
A passage of a weak cold front brought low stratus to all but the
far southern part of the forecast area this morning. The stratus
had slowed fog development, so there was no plan to expand the
Dense Fog Advisory beyond far northern WI. Although widespread
dense fog was not occurring in the far north, visibilities were
below a mile in parts of Vilas County, and very low ceilings
(200-500 ft) had potential to lower to the surface over the next
couple hours, so headlines were maintained. Temperatures were in
the 50s and lower 60s.
Fog is expected to mix out by 14z-15z this morning, but low
stratus will likely linger until late morning or early afternoon.
Partial clearing in the afternoon should allow for a slight
warmup, with highs reaching into the upper 60s to middle 70s. The
high will persist across the region through Friday, along with dry
conditions and continued potential for fog, locally dense, late
tonight into early Friday. More sunshine on Friday should allow
temperatures to reach well into the 70s, though southeast winds
will keep readings in the 65 to 70 range near Lake Michigan.
The high pressure system will edge east Friday night into
Saturday, allowing the front to return as a warm front. Scattered
showers and thunderstorms are expected to develop as this occurs.
Models have a difference of opinion on where the main band of
showers and storms will form, with some showing from near the
WI/Upper MI border into far NE WI, and others south of Hwy 29,
closer to the SFC/H8 warm fronts. Given this uncertainty, decided
to keep chance pops across all of the forecast area. The showers
should exit the region Saturday morning, with dry weather
returning for the rest of the weekend as strong upper level ridging
occurs. The chance of showers and storms returns as the upper
ridge shifts east next week and southwest flow brings a more moist
and unstable air mass and periodic short-wave energy to the
western Great Lakes. The best chance of showers and storms
arrives Wednesday into Thursday, as a cold front and upper trough
impact the region.
Temperatures will remain close to normal today, then rise above
normal from Friday through next Thursday, with highs reaching the
upper 70s and lower 80s in most areas.
&&
.AVIATION...for 12Z TAF Issuance
Issued at 636 AM CDT Thu Sep 11 2025
Widespread low stratus and patchy fog will impact aviation
operations early this morning, but conditions will steadily
improve during the mid to late morning, with most locations
returning to VFR by early afternoon. Conditions will be favorable
for stratus and fog development again late tonight.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....Kieckbusch
AVIATION.......Kieckbusch

NWS GRB Office Area Forecast Discussion