500
FXUS63 KGRB 081653
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1153 AM CDT Wed Jul 8 2026

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- There is a 15-30% chance of severe thunderstorms along with
  heavy rain possible this afternoon and evening, primarily across
  central and east-central Wisconsin. Damaging winds and localized
  flooding will be the main threats, but small hail and an
  isolated tornado are also possible.

- Continue to monitor the potential for excessive heat early next
  week as high temperatures rise into the low to middle 90s on
  Monday and Tuesday.

&&

.DISCUSSION...
Issued at 122 AM CDT Wed Jul 8 2026

A complex of thunderstorms across Minnesota was working into
northwest WI early this morning. There have been a few warnings
with this complex so far. This complex is expected to move
into north-central WI between 09z-12z and across far northeast WI
after 12z. Several models continue to show convection developing
south of the current cluster of storms towards 12z that could
impact locations south of Highway 29. Previous forecast had pops,
thus not much change in this area. Later this morning into the
afternoon, several solutions to contend with that leave some
questions in how widespread severe weather will be. This was
seen in the Storm Prediction Center Day 1 Outlook that has shifted
the Slight Risk (Level 2) is little further south. The latest
HRRR would support the morning convection south of Highway 29
with another complex developing along and south of the Highway 29
corridor later this afternoon, between 2 pm and 4 pm west of the
Fox Valley, and from 4 pm to 7 pm for Green Bay and the Fox Valley
east to the lakeshore. Bufkit soundings indicated 1,000 to 2,000
J/KG of CAPE and 0-6 km shear values around 30 knots to support
severe storms. Strong/damaging winds and heavy rainfall that could
lead to localized flooding are the main risk. Small hail and an
isolated tornado are also possible. Showers and scattered storms
will continue tonight, ending across the north late. Showers and
a few storms will continue across east-central WI through the
night into Thursday.

The chances of showers and storms continue into Thursday afternoon
across central and east-central WI, although severe weather is not
expected. Dry conditions expected this weekend into early next
week. 500mb ridge building across the central United States early
next week will bring well above normal temperatures along the
potential for excessive heat and heat related impacts as high
temperatures Monday and Tuesday will be in the upper 80s to middle
90s.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1153 AM CDT Wed Jul 8 2026

Late this morning, a cold front stretches from west-central
Wisconsin to north-central Wisconsin. MVFR to IFR ceilings exist
along and north of the front while VFR conditions prevail to the
south and south of RHI.

This front will provide the focus for clusters of showers and
storms this afternoon and evening. Thunderstorm redevelopment is
expected 19-20Z with impacts into RHI/AUW/CWA starting during this
timeframe. These storms are expected to increase in coverage and
proceed into the Fox Valley in the 22-23Z period. Strong storms
are likely with gusts in excess of 40 mph possible with ceilings
and visibilities falling to MVFR and IFR/LIFR respectively.
After the initial push of storms, scattered showers with embedded
thunder looking to continue through much of the evening, while
light showers could persist across parts of central and east-
central WI into Thu morning.

Late tonight, there is a decent signal for ground fog to develop.
Central and north-central WI have potential for sub-IFR
visibilities. The fog should lift into a MVFR stratus deck after
about 15Z.

Winds will be light over the period.

&&

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

&&

$$

DISCUSSION.....Eckberg
AVIATION.......MPC

NWS GRB Office Area Forecast Discussion