543
FXUS63 KGRB 091131
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
631 AM CDT Wed Sep 9 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Gusty west winds of 25 to 30 mph, with localized gusts up to 35
  mph over north-central Wisconsin, this afternoon.

- Periods of showers and thunderstorms return late Friday through
  Monday. Greatest chance for severe storms is currently expected
  to come Monday afternoon/evening.

&&

.DISCUSSION...
Issued at 204 AM CDT Wed Sep 9 2026

Storm Chances: A narrow band of showers and thunderstorms is
developing across central WI early this morning along a slow moving
cold front. As this front continues east across the area expect
continued scattered storm development from central to far
northeast WI through mid morning before the region drys out.
Behind the front a much drier air mass will move into the region
leaving mostly dry conditions for the remainder of the work week.
Next chance (60-70%) for showers/storms comes late Friday into
Saturday as an upper trough drags another cold front across the
region. While a few stronger elevated storms capable of producing
hail and 40-50 mph wind gusts are possible with 500-800 J/kg of
MUCAPE and 30-35kts of deep-layer shear, a strong cap around 800mb
will limit the potential for surface based storms and the risk
for severe storms.

Global ensembles are more impressed with the severe/heavy rain
potential on Monday as a seasonally strong upper jet streak (55-
60kts) overspreads a moist and unstable airmass. There is still a
lot of uncertainty with the details for Monday, but it will be a
period of monitor, especially for those with outdoor plans.

Windy Today: A tightening pressure gradient and deep mixing today
will lead to breezy west to northwest winds. Strongest gusts of 25-
35 mph are expected this afternoon. As the pressure gradient
relaxes winds will trend lighter Thursday.

Temperatures Trends: Temperatures will remain a few degrees warmer
than normal today before becoming more seasonal Thursday.
Temperatures will then trend near to slightly above normal through
the weekend and into early next week. There is some signal for a
cooler period arriving towards the end of next week.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 631 AM CDT Wed Sep 9 2026

An area of mid-leve status continues to drift east early this morning
with a back edge  extending from KMNM to KISW. Below the overcast
status deck there are a few pockets of low status creating MVFR cigs
over the Fox Valley. These lower cigs should clear out by mid
morning with mostly clear skies expected for the remainder of the
TAF period. Across central and northern WI where skies are clear
patchy areas of shallow ground fog have developed creating isolated
pockets of IFR conditions. Fog will clear out by 13-14Z as winds
begin to increase and mixing deepens. By late this morning expect
breezy northwesterly winds to develop with sustain winds around 10-
15 kts and gusts reaching 20-25kts through the afternoon. Winds will
diminish this evening.

&&

.MARINE...
Issued at 204 AM CDT Wed Sep 9 2026

Another Small Craft Advisory may be needed this afternoon/evening
for increasing west winds, but forecast wind gusts have trended
weaker over recent forecast cycles. Have held off on issuing new
marine headlines at this time given the uncertainty with wind gusts
as well as the relatively short duration of the stronger gusts this
afternoon.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement until 7 AM CDT this morning for WIZ022-
040-050.
&&

$$

DISCUSSION.....GK
AVIATION.......GK
MARINE.........GK

NWS GRB Office Area Forecast Discussion