NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 252357
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
657 PM CDT Mon May 25 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- The potential for rain and thunderstorms for Tuesday afternoon
  has increased, with a few strong to marginally severe storms
  possible with large hail and strong winds.

- Above normal temperatures are expected through the week, with
  highs forecast mainly in the upper 70s and 80s. A few spots may
  approach or reach 90 degrees on Tuesday.

- Due to persistent southerly winds and building waves, Small
  Craft Advisories and Beach Hazard Statements begin on Lake
  Michigan at 4:00 PM today.

&&

.DISCUSSION...
Issued at 301 PM CDT Mon May 25 2026

Precipitation...There have been a few weak radar echos in east-
central WI this afternoon, but no reports of anything reaching the
ground, which aligns with the fact that cloud bases are around
10kft and there is fairly dry air beneath them. Removed any PoPs
for the rest of today as chances are very minimal at this point.

CAMs showing a few showers popping up late tonight, although
confidence in this occurring is low given the lack of forcing and
dry air still present. Added a few 15-20% PoPs late tonight into
Tuesday morning. The main opportunity for any rain and
thunderstorms comes Tuesday afternoon and evening as a cold front
slowly sags south across Wisconsin. Steep low-level lapse rates
and MUCAPEs of 1500-3000 J/kg (depending on the model) develop
during peak heating, which would be sufficient to produce
scattered thunderstorms capable of producing marginally strong to
severe hail and winds. CAMs have also become more robust with
this development over the past couple runs. SPC has added the
southern two-thirds of the forecast area to the Marginal Risk
(level 1/5) of severe storms for Tuesday, which is reasonable.
Showers and storms weaken and dissipate Tuesday evening.

There remains a small chance (20-30%) of showers and thunderstorms
Wednesday afternoon; then surface high pressure dominates the
area from Thursday through next weekend which will result in
little to no precipitation.

Temperatures...Readings will trend above normal for the next
week, peaking Tuesday with highs the 80s to possibly low 90s. NBM
shows a 50-75% probability for parts of central into northeast WI
reaching or exceeding 90 degrees. While dew points will be
tolerable in the 50s to low 60s, there is a moderate (level 2 of
4) heat risk, meaning prolonged periods outside could affect those
who are sensitive to heat.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 639 PM CDT Mon May 25 2026

Quiet conditions are expected through Tuesday morning, with only a
small chance of showers in northern WI late this evening into the
early overnight, and some LLWS late tonight. A cold front will sag
south across the forecast area on Tuesday, with scattered
thunderstorms developing during the mid to late afternoon, and
continuing across C/EC WI into the evening. For now, have just
added Prob30 for thunderstorms the last couple hours of the TAF
period.

Southwest winds will gust to around 15 kts at times through most
of the TAF period, but will turn NW-NE across NC/NE WI in the wake
of the frontal passage Tuesday afternoon.

&&

.MARINE...
Issued at 301 PM CDT Mon May 25 2026

Persistent southerly winds gusting to 20 to 25 kts late this
afternoon into this evening will result in building waves to 3 to
5 ft along the Lake Michigan nearshore waters. No changes to the
Small Craft Advisory which runs from 4PM today through 7AM Tuesday
for the Lake Michigan nearshore waters. Given the higher waves
and the holiday, a Beach Hazards Statement for Lake Michigan
beaches in Manitowoc, Kewaunee, and Door counties also remains in
effect for the same time despite the swim risk being moderate
(instead of high).

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement through Tuesday morning for WIZ022-040-
050.
&&

$$

DISCUSSION.....KLJ
AVIATION.......Kieckbusch
MARINE.........KLJ