Green Bay, Wisconsin 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

658
FXUS63 KGRB 040704
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
204 AM CDT Mon May 4 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Warm and breezy today with lower RH values. 60-90% chance of
  wind gusts 35 to 40 mph central to eastern WI. Elevated fire
  weather conditions where fine fuels have dried out and green up
  is not as advanced.

- Band of showers and storms (20-40% chance) develops mid to late
  afternoon, especially southern Fox Valley to the lakeshore.
  Stronger storms could produce wind gusts 40-50 mph.

- Temperatures fall below normal for the rest of the week. Risk
  for Frost/Freeze Headlines ramps up beginning Tuesday night.

&&

.DISCUSSION...
Issued at 204 AM CDT Mon May 4 2026

Breezy and warm today with elevated fire weather conditions. Also,
still a small chance of some showers and storms, especially later
in the afternoon. Cooler for the rest of the week, with frost/freeze
headlines likely needed multiple nights.

Elevated fire weather conditions today: Cold front over northern
MN arrives late today. Ahead of the front, another warm and breezy
day is expected today. Highs will reach the lower to middle 70s
where clouds will not be as prevalent early on (north-central).
That will have to be monitored though as it will be gusty there as
well with low RH values. Based on deep mixing, wind gusts should
reach 35 to 40 mph, with even isolated higher gusts late morning
through mid afternoon. Strongest winds will be from central to
eastern WI (60-90% chance of gusts over 35 mph). Conditions will
be most favorable for fire spread where green up is not quite as
advanced, but with the gusty winds and warm temps (10-15 above
climo), have issued an SPS for all areas except north-central.

Shower and storm potential this afternoon: Dry airmass will impact
potential for showers and storms mid to late afternoon. Upstream
soundings at Omaha, Davenport are quite dry, so even with the
front moving in during peak heating, dry air and some evidence of
capping up to H7 looks to limit convective potential. Used gradient
of MLCAPE (up to 400J/kg) as guide and placed narrow ribbon of
chance pops from southern Fox Valley to the lakeshore. A few
showers could occur northwest of this area, but this is where
thunder is most favored. Given winds aloft and inverted-V look to
soundings, if a storm develops, gusty winds 40-50 mph would be in
play. Honestly, given the winds aloft, even a more developed
shower could pull down similar wind gusts this afternoon. Will be
a near term forecast item for dayshift to keep tabs on. Any
showers quickly end early this evening and it will be a bit
breezy behind the front as well as cooler air begins to arrive.

Cooler with frost/freeze potential rest of the week: Small chances
for a few showers or sprinkles cannot be ruled out Tue or Wed over
northern WI. Better chances still in forecast for Thursday all
areas as stronger wave crosses the region. May be just cold enough
for some graupel or snowflakes to mix with the showers that day,
at least during the morning. Frost/Freeze potential highest Tuesday
night through Thursday night, and maybe on Friday night as well.
Right now, appears that greater frost potential is setting up
more west of the Fox Valley and lakeshore. Daytime temperatures
will mainly be in the 50s, though highs likely stay in the 40s
over the far north. Temperatures will begin to rebound to around
climo starting next weekend.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1041 PM CDT Sun May 3 2026

Behind a cold front, mostly clear skies prevail across the region
late this evening. Mid and high clouds will return and lower late
tonight.

LLWS is expected to develop by 07z at KRHI and after 11z at the
other terminals, then diminish as winds mix down 14-15z. Surface
winds will then gust to 25-30 knots out of the southwest until
early Monday evening.

Another cold front will shift over the area from northwest to
southeast late Monday morning through the afternoon. Ahead of the
front, shower coverage is looking sparse and confidence remains
low. However, there seems to be sufficient saturation for a prob30
group at KRHI on Monday afternoon. Decided to maintain the dry
forecast at the other terminals. Will continue to monitor trends
over east- central WI for a shower addition in later taf cycles.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......MPC