789
FXUS63 KGRB 031708
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1208 PM CDT Mon Aug 3 2026

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- There is a 20-40% chance of rain across the region on Tuesday,
  with a 50-80% chance Tuesday night across east-central
  Wisconsin and the lakeshore. The severe weather risk is low.

- There is a 20-40% chance of rain lingering Wednesday and
  Wednesday night across east-central Wisconsin and the lakeshore.
  The severe weather risk will remain low.

- There is a 30-50% chance for rain at times during the upcoming
  weekend.

&&

.DISCUSSION...
Issued at 151 AM CDT Mon Aug 3 2026

Dry weather through tonight...

Latest IR satellite imagery indicates despite temperatures near
the dew point, clear skies, and light winds, fog is not forming
across the region. In addition, recent model and ensemble data is
less bullish on fog formation early this morning other than some
patchy fog and minor visibility restrictions. Therefore, fog is
not expected to have much of an impact this morning or during the
morning commute. High pressure will keep the weather dry across
the region through tonight.

A cold front brings rain chances Tuesday through Wednesday
night...

A cold front sinking south will bring a chance (20-40%) of rain as
it tracks through the region Tuesday. The initial surge will not
have much in the form of dynamics; therefore, precipitation is not
expected to be ubiquitous with this first shot.

The front stalls across the western Great Lakes region Tuesday
night as the main surface low lifts north from the southern Plains
and strong mid level frontogenesis develops along the front. This
will bring an increased chance (50-80%) for showers and
thunderstorms Tuesday night across east-central Wisconsin and the
lakeshore. Modest instability (MUCAPEs of 500-1000 J/kg) and shear
(25-30 knots) should keep storms below severe limits. PWATs up to
2 inches and long skinny CAPE profiles will mean excessive rain
will be a threat, especially Tuesday night across eastern
Wisconsin.

The front will sink a bit farther southeast as a mid level trough
and attendant shortwave track through the western Great Lakes.
This will bring a continued chance (30-50%) for additional showers
and thunderstorms across this same area Wednesday and Wednesday
night. Given the front will be a bit farther southeast, the
additional rainfall should mainly be a glancing blow during this
period with the heaviest rain expected to be southeast. Continued
high PWATs of 1.5 to 1.75 will mean excessive rainfall will still
be a threat, especially for areas that receive repeated rounds of
heavy rain during this period.

Dry weather expected late in the week with active weather again
for the weekend...

High pressure is then expected to bring dry weather Thursday and
Friday across the area. Another cold front sinking south will
bring additional chances (20-40%) for the upcoming weekend. NWP
models and ensembles are murkier for the upcoming weekend as
timing and placement of the upcoming thunderstorms across the
region differ quite a bit. Therefore, the entire weekend will
neither be completely dry or a complete washout.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1207 PM CDT Mon Aug 3 2026

Relatively good flying weather is expected through most of the TAF
period. Widely scattered fair weather clouds are expected this
afternoon, which should dissipate by early evening. High clouds
will increase across the region tonight ahead of the next cold
front. A brief period of low level wind shear is possible over
north-central WI which could impact RHI between 09-13Z Tue.

Clouds thicken and lower on Tuesday morning as a cold front moves
into the region. A period of MVFR ceilings is possible at
RHI/AUW/CWA after 15Z Tue. Models depict scattered shower
activity along the front, and will add a prob30 group to RHI.

Southwest winds under 10 kts through tonight will become gusty up
to 20 kts on Tuesday before veering to the west behind the front
on Tuesday afternoon.

&&

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

&&

$$

DISCUSSION.....Kurimski
AVIATION.......MPC

NWS GRB Office Area Forecast Discussion