830
FXUS63 KGRB 161730
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1230 PM CDT Sun Aug 16 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Isolated to scattered showers (10 to 30% chance) possible
  mainly along the Door peninsula this afternoon.

- Shower and storm chances (20 to 50%) return late Monday night,
  continuing through Tuesday. Potential for excessive rainfall
  and severe weather have decreased.

- Drought conditions expected to worsen due to rainfall deficit
  and little to no chances for wetting rain in the forecast.

&&

.DISCUSSION...
Issued at 1200 PM CDT Sun Aug 16 2026

This afternoon... Brief shower chances remain possible through
this afternoon mainly along the Door peninsula as weak frontal
boundary gradually shifts east. With little to no upper support
and limited instability due to cloud cover, have for the most part
kept thunder out of the forecast. Increasing gradient winds behind
the front may result in 20 mph gusts across the area through this
afternoon.

Minimal shower/storm chances... Better chances for scattered
showers and embedded thunder come Monday through Tuesday as stout
northwest flow brings another front through the upper Mississippi
Valley. Most recent suite of model runs retain the trend of
quicker and earlier FROPA late Monday night into Tuesday morning;
as such, excessive rainfall and severe potential have gone down.
Regardless, airmass behind the front doesn`t look particularly
juicy, with better moisture transport from the Gulf remaining to
our southwest anyway. WPC has thus shunted both the slight and
marginal ERO to the south, though marginal risk remains
along/south of Hwy 10. Any excessive rain potential would likely
come with training storms or repeated showers. Cannot rule out the
possibility of a diurnal storm or two, possibly on the stronger
side, as modest instability (500 to 700 J/kg) coincides with 40+
knots of bulk shear during peak heating.

Cooler and more stable air filters in behind the front on
Wednesday, with temperatures steadying out in the upper 70s to low
80s. Next period of concern would then be Friday into Saturday as
potent shortwave and attendant front traverse the Midwest. Though
storm predictability is low this far out, ML guidance paints a
broad 5 to 15% prob severe, so will continue to monitor.

Worsening drought conditions... Forecast concerns gradually shift
to worsening drought conditions due to the lack of wetting rain
we`ve received recently. Additionally, little to no relief is in
sight as better jet dynamics remain to our north with greater
moisture return/instability reserve holed up to our south. As of
August 11th, the majority of Wisconsin sits in D1 drought status
(Moderate), with pockets of D2 (Severe) drought across northwest
and north-central Wisconsin where they have received only 25 to
50% of normal precip over the past 30 days. If current dry spell
continues, fire weather concerns could come into play during late
summer/early fall due to low afternoon RHs and drying fuels.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1200 PM CDT Sun Aug 16 2026

MVFR stratus deck behind the front persists over the northwest
half of the state as of early this afternoon, though improvement
to VFR stratocu is expected at all terminals within the next few
hours as the front shifts east. Low MVFR/IFR stratus then
increases from the north late tonight into Monday morning, though
could be similar situation to this morning where patchy fog and
locally reduced vsbys end up manifesting.

Winds continue to veer and increase out of the northwest early
this afternoon, with gusts to 20 knots possible into this evening.
Winds then subside overnight, becoming light and variable into
Monday morning.

&&

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

&&

$$

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

NWS GRB Office Area Forecast Discussion