NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 091130
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
630 AM CDT Sun Aug 9 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Showers and storms return later this morning. Main severe risk
  remains over southern Wisconsin, though gusty winds and heavy
  rain will be possible with any storm activity.

- Additional rounds of showers and storms through the middle of
  next week, though confidence in storm timing and severity
  remains low.

- Slightly cooler in the 70s today. High temperatures in the low
  80s early to mid-week, followed by a cooling trend late next
  week.

&&

.DISCUSSION...
Issued at 1135 PM CDT Sat Aug 8 2026

Rain/storm chances... Prior forecasts remain on track as prevailing
northwest flow containing several embedded shortwaves brings
periodic chances for rain/storms through the better part of next
week. Greatest opportunity for heavy rain and storms look to be
later this morning as surface low crosses the upper Mississippi
Valley, though severe chances remain nebulous. Better jet dynamics
remain off to our south during this time, and environment looks
relatively capped from around 850 to 700 mb up into northeast
Wisconsin. Regarding heavy rainfall potential, LREF probabilistic
guidance only shows a 10 to 15% chance for receiving 1" of rain
across our southern tier of counties through Monday morning.
However, timing of the boundary will play a large role in whether
or not we can get excessive rain, as some long-range models hint
that the front might stall out over southern Minnesota into
central Wisconsin. In this case, we would mostly rely on training
storms to get heavy rain across portions of central to east-
central Wisconsin.

Next noteworthy chances for rain/storms look to come late Monday
into Tuesday, though similar pattern emerges where better
dynamics look to remain holed up to our south in proximity to the
front. Suspect that any storms that are able to get going would
be more diurnally-driven Tuesday afternoon. More or less rinse and
repeat for Wednesday until the front shifts far enough south that
we're afforded a brief dry spell.

Extended... Temperatures to read generally in the low 80s through
mid-week as upper flow flattens out and weakens. Signal for a
cooler and drier pattern shift then exists late next week as
polar airmass builds to the north and is transported south via
troughing regime. Highs will fall into the 70s for most during
this time.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 615 AM CDT Sun Aug 9 2026

Low clouds will continue to increase this morning as a cold front
approaches from the west, bringing our next chances for
showers/storms. Greatest chances for storms look to be associated
with SCT to BKN convection over the central Wisconsin sites this
morning; have thus added PROB30 inclusions of TSRA at AUW and CWA
through 16Z. Showers and storms then diminish in coverage as they
track further east. Expect reductions to MVFR, and even locally
IFR, cigs during this time. Vsbys may also drop into IFR territory
where a heavier shower or storm moves directly over a TAF site.
Conditions then return to VFR by this evening. Otherwise, southerly
winds gradually veer to northerly into tonight, gusting to 15
knots this afternoon. Patchy to areas of fog may then develop due
to remnant moisture near the surface toward the end of the TAF
period.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION.....Goodin
AVIATION.......Goodin