NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 251904
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
204 PM CDT Thu Jun 25 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Scattered showers and isolated thunderstorms ending late this or
  early this evening.

- Below normal temperatures through Friday, then a warming trend
  for the weekend.

- Building heat and humidity will potentially bring heat-related
  impacts next week. Along with the heat, there are periodic
  chances of thunderstorms, which some of the storms could be
  strong or severe at times.

&&

.DISCUSSION...
Issued at 204 PM CDT Thu Jun 25 2026

Scattered showers and isolated thunderstorms will continue to move
southward this afternoon. It was a cool afternoon with temperatures
in the middle 60s to lower 70s.

For the rest of the afternoon and tonight, the showers and isolated
storms will come to an end by early evening, then skies become
clear to partly cloudy. Lows tonight should drop into the middle
40s to middle 50s. On Friday, partly cloudy skies prevail with
highs in the lower to middle 70s. Over the weekend, temperature
will gradually warm, returning to near normal levels on Sunday.
Saturday will be tranquil, but still some question marks on how
quick the rain returns Sunday and Sunday night. Do have low pops
(15-30% chance) going due to uncertainty if showers/storms arrive
during the day Sunday. Rain chances increase to 30-50% Sunday
night as low level jet increases to 30 knots and warm front lifts
northward. The GFS bufkit sounding indicated 0-6km shear values of
30 knots and CAPE values around 1,500 J/KG to get some possibly
strong/severe elevated storms. However, wetbulb zero heights are
near 13,000 feet which may lower the risk of large hail.

500mb ridge is expected to build across the eastern United States
early next week, bringing heat and humidity. The region will be
in the ring of fire with periodic chances of thunderstorms through
the week. With the warm front north of the area, gusty southwest
winds and very warm 850mb temperatures around 25C support highs
close to 90 on Monday. With dewpoints rising in the upper 60s to
lower 70s will result in the heat index climbing to 95F to 105F.
Monday night will be very warm with lows in the upper 60s to
middle 70s. For Tuesday and Wednesday, it will be downright hot
if we don't see any thunderstorm activity. Models are differing
on the southward extend of thunderstorm complexes moving around
on the backside of the ridge. Confidence is lower with the
expected high temperature and maximum heat index values with on
Tuesday and Wednesday due to the potential for convection both
days. The Canadian model would suggest both days would be
active, with the potential for strong/severe storms.  The latest
12z ECMWF also supports for an active day on Tuesday. From Tuesday
through Friday, there will be periodic chances of thunderstorms.
Timing these features this far out is difficult at best. It does
appear to be an active pattern.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1214 PM CDT Thu Jun 25 2026

Scattered showers and isolated storms will continue to sink
southward this afternoon. The probabilities of thunder was so
low, only went with a tempo group for showers at the TAF sites.
Also, any lingering MVFR CIGS will rise into the VFR category
during the afternoon. Skies will become clear to partly cloudy,
with only high clouds streaming across central and east-central
WI after sunset. Fair weather cumulus is expected to develop
again late Friday morning from 1,500 to 2,500 feet.

&&

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

&&

$$

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