Scandinavia, Wisconsin Weather Forecast Discussion

095
FXUS63 KGRB 090924
AFDGRB
Area Forecast Discussion
National Weather Service Green Bay WI
424 AM CDT Tue Sep 9 2025
Forecast discussion for routine morning forecast issuance
.KEY MESSAGES...
- Temperatures climbing back to or slightly above seasonal normals
  this week, with highs in the 80s in spots possible Friday and
  Saturday.
- Chances (30-60%) for rain showers and a few storms today through
  Wednesday, especially west and north of the Fox Valley/lakeshore
  areas.
- Conditions hazardous to small craft, along with dangerous
  swimming conditions, expected on the bay and Lake Michigan
  through this afternoon/evening.
- Chances for showers and thunderstorms return for the start of
  the weekend.
&&
.DISCUSSION...
Issued at 424 AM CDT Tue Sep 9 2025
A cold front was situated across NW MN early this morning. Showers
and scattered thunderstorms had develop ahead of the front in NE
MN, far northern WI and the Upper Peninsula of MI, in conjunction
with a short-wave, H8 WAA on the nose of a 40-50 knot LLJ, and
PWATs of 1.25-1.5 inches. So far, shower activity had mainly
impacted Vilas County through the overnight hours.
Moisture (PWATs 1-1.3 inches) will continue to increase across
the region today and tonight, ahead of the cold front. The front
is expected to weaken as it moves through the forecast area late
tonight into Wednesday, and upper forcing will also be weak. Will
gradually spread chance pops through the NW half of the forecast
area today, then to the western Fox Valley/bay tonight. Will also
add some fog over the northwest half overnight. Isolated to
scattered showers should linger into Wednesday, especially over
northern WI. Models show little instability (mainly less than 250
j/kg) through this period, and keep most of the rain west and
north of the Fox Valley through Wednesday. Have capped storm
chances at 20 percent or less with this system, given the paltry
instability.
High pressure builds into the region as the front shifts southeast
Wednesday night, and should bring dry weather through most of
Friday. 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 expectedto develop as this occurs.
Dry weather should return late in the weekend as strong ridging
aloft builds across the western Great Lakes.
Temperatures will remain close to normal through midweek, then
rise above normal Friday into Saturday, with highs reaching the
upper 70s and lower 80s in most areas.
&&
.AVIATION...for 06Z TAF Issuance
Issued at 945 PM CDT Mon Sep 8 2025
Winds at the surface continue to die down late this evening as
850 mb winds gradually ramp up. LLWS thus remains a concern
across the western TAF sites during the beginning of the TAF
period (until ~12Z). South/southwest winds briefly pick up Tuesday
afternoon with better mixing, with widespread gusts to 20 knots
possible.
CAM consensus continues to shows the brunt of the precip remaining
to our north overnight, with showers not making it down to RHI
until late Tuesday morning/early afternoon. Opted to include
-SHRA across all western TAF sites by Tuesday evening, though
withheld mention of thunder due to low confidence. Possibility of
localized IFR cigs creeping into the far north toward the end of
the TAF period.
&&
.MARINE...
Issued at 424 AM CDT Tue Sep 9 2025
Southwest/south winds will gust to around 25 kts into this
afternoon, then diminish later today into tonight. No changes
were made to the Small Craft Advisory (and Beach Hazards
Statements), with the bay ending around midday today as winds
decrease, and Lake Michigan ending later this afternoon/evening
as waves slowly subside. The large waves will result in dangerous
swimming conditions at Lake Michigan beaches through late
afternoon/evening.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement through this evening for WIZ022.
Beach Hazards Statement through this evening for WIZ040-050.
&&
$$
DISCUSSION.....Kieckbusch
AVIATION.......Goodin
MARINE.........Kieckbusch

NWS GRB Office Area Forecast Discussion