017
FXUS63 KGRB 271947
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
247 PM CDT Mon Jul 27 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Lingering heat indices are forecast into the upper 90s to low
  100s across central Wisconsin this afternoon and early evening.

- Gusty northerly winds will build waves from 3 to 5 feet on Lake
  Michigan south of Two Rivers this evening into Tuesday
  afternoon.

- Otherwise quiet conditions this week behind the active weather
  from today. Active weather potential will remain minimal until
  the end of the week.

&&

.DISCUSSION...
Issued at 247 PM CDT Mon Jul 27 2026

Much quieter conditions are expected to move into the region
behind the very active start to the day. Mean surface flow will
likely remain southerly through the afternoon, which will prolong
the heat impacts to central Wisconsin until the evening. A few
heat indices will likely continue to touch into the upper 90s to
lower 100s before winds shift over to the north overnight.

Quieter and much drier arrives tonight as winds pick up from the
north. Gusts up to 20 to 25 mph at times will help usher in a dry
and sunny day Tuesday as high pressure moves into the region.
Temperatures are expected to remain near or above normal on
Tuesday before warm air advection again increases through the
middle of the week. High temperatures on Thursday could get back
towards the middle to upper 80s and maybe even low 90s, which
could produce a few sporadic showers in the afternoon. Still, no
widespread active weather is expected until sometime Thursday
night into Friday with the next frontal passage. Rain and storms
then stick around Friday into early Saturday before some quieter
conditions return for the latter half of the weekend.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1246 PM CDT Mon Jul 27 2026

Strong thunderstorms will be working their way through the region
at the beginning of the TAF period, impacting GRB, ATW, OSH, and
MTW for the first few hours. Included thunder and a TEMPO for the
leading wind gusts. Behind this, a period of MVFR ceilings will
be in the area for the afternoon but signs point to clearing as
winds gradually shift northwards through the evening. Expect the
drier conditions to help clear out fog potential for the overnight
hours.

Outlook: High pressure brings widespread VFR conditions and
lighter winds Tuesday into Wednesday.

.KOSH...
Thunderstorms expected to roll through the Oshkosh area through
the next hour or two, accompanied by lightning, strong winds, and
possibly brief hail. Active weather should move through quickly
followed by a period of MVFR ceilings around 2-3k ft. Additional
convection behind the morning storms appears unlikely at this
time, so kept the rest of the forecast quiet. As winds become
light and more northerly behind the storms, expect clearing skies
for the late evening and overnight period which should bring back
VFR conditions overnight into Tuesday morning.

&&

.MARINE...
Issued at 247 PM CDT Mon Jul 27 2026

A tightening pressure gradient will cause northerly winds to
increase to 15 to 25 knots tonight into Tuesday. Waves will build
to 3 to 5 feet on the Lake Michigan nearshore waters south of Two
Rivers, and a Small Craft Advisory will be issued. Winds and waves
will gradually subside Tuesday afternoon as high pressure builds
in from the north.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT this evening for WIZ035-036-045.
&&

$$

DISCUSSION.....Uhlmann
AVIATION.......Uhlmann
MARINE.........Uhlmann

NWS GRB Office Area Forecast Discussion