Starlake, Wisconsin Weather Forecast Discussion

982
FXUS63 KGRB 121748
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
1248 PM CDT Fri Sep 12 2025
Updated aviation portion for 18Z TAF issuance
.KEY MESSAGES...
- Showers and scattered thunderstorms this evening through
  Saturday morning. Severe weather is not expected, but an
  isolated strong storm or two is possible.
- Areas of dense fog on Lake Michigan into Saturday. Marine Dense
  Fog Advisory in effect.
- Above normal temperatures through next week, with small rain
  chances middle to late part of the week.
&&
.DISCUSSION...
Issued at 400 AM CDT Fri Sep 12 2025
High pressure, light winds and good radiational cooling conditions
have resulted in widespread fog and low stratus development across
the forecast area this morning. Most observing sites had vsbys in
the 1/4sm-1sm range, except in the far western tier of counties,
where low stratus was more prevalent. Temperatures were quite
cool, in the 40s to middle 50s. A Dense Fog Advisory has been
issued for the entire forecast area through 10 am today.
The high pressure system will edge east tonight into Saturday,
which will allow a warm front to lift into far southern WI.
Southwesterly 850 mb flow will increase to 20 to 25 kts tonight,
resulting in increased WAA, with frontogenetic forcing and the
passage of a short-wave trough providing additional lift. Models
have trended toward more instability, with MUCAPE of 500-1000
j/kg, and deep layer shear has also edged up to 25 to 35 kts.
Have increased pops to high-end chance to low-end likely, and now
acknowledge the potential for a stray strong storm or two with
heavy downpours and small hail. The main item of contention is
where the main precipitation bands will set up, as models offer
varying opinions. For now will focus the highest pops over
northern WI during the evening, then mainly along and south of Hwy
29 for the overnight period. The showers should exit the region
Saturday morning.
Dry weather returns for the rest of the weekend as strong upper
level ridging occurs, and this will likely linger into early next
week. A chance of showers and storms arrives during the mid to
late part of the next work week, as the upper ridge shifts east
and an upper trough and weak cold front edge east across the
region.
Temperatures will remain close to normal today, then rise above
normal for much of the next week, with highs reaching the upper
70s and lower 80s on most days.
&&
.AVIATION...for 18Z TAF Issuance
Issued at 1247 PM CDT Fri Sep 12 2025
Fog and low stratus from earlier has diminished. MTW may be
close enough for brief appearance of lower conditions early in TAF
period as dense fog is lurking just to the east on Lake Michigan.
Otherwise, only expecting high clouds rest of today, with little
cu.
Showers and storms ongoing over MN and Dakotas likely come through
in a couple waves tonight. First wave (eastward extension of
activity currently southwest of DLH) will impact west/north this
evening (perhaps as early as 22-23z at RHI) mainly in the 00z-04z
window, with second wave occurring mainly central and east-central
after midnight through daybreak on Saturday (06z-12z). Showers
and storms may linger through mid morning (15z) far east-central,
mainly impacting MTW. Conditions may drop to MVFR from vsby
and/or cigs during showers and storms. On Saturday, mainly VFR
cigs early on will drop to MVFR late morning into the afternoon.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION.....Kieckbusch
AVIATION.......JLA

NWS GRB Office Area Forecast Discussion