534
FXUS63 KGRB 220626
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
126 AM CDT Sat Aug 22 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Isolated to scattered showers and storms (30-50% chance)
  expected over north-central to eastern WI, mainly in the
  afternoon. A strong storm with gusty winds and hail is possible.

- Dry weather returns Sunday and Monday, with a period of
  unsettled weather arriving for the middle of next week.

- Slightly below normal temps this weekend, then a return to near
  normal readings for most of next week.

&&

.DISCUSSION...
Issued at 126 AM CDT Sat Aug 22 2026

This Weekend...Recent rainfall, mostly clear skies and light
winds has led to some patchy ground fog development, especially
across northern WI. Some clouds moving in should help keep the
fog in check, but at least some patchy fog will continue early
this morning, then burn off after sunrise. Northwest, cyclonic
flow will prevail across the Great Lakes through the weekend with
a couple shortwaves moving with this flow bringing chances for a
few showers and storms. The first weak shortwave arrives this
morning, bringing a stray shower or sprinkle across far northern
WI. A second shortwave will dive across northeast WI this
afternoon, bringing isolated to scattered showers and storms
(20-50% chance) mainly to far northern and eastern WI. While weak
deep layer shear (under ~25 kts) will limit overall organization
of the storms and the severe threat, SBCAPE of up to ~1200 J/kg,
inverted-V soundings and very steep low-level lapse rates will
promote some gustier winds and small hail in the stronger
showers/storms. Northwest winds will increase to 15 to 25 mph this
morning and afternoon.

Surface high pressure and drier air will keep the area dry tonight
into Sunday. Northwest winds will be a little lighter on Sunday,
but still gust to 20 mph.

Next Week...Dry weather continues on Monday, then another
shortwave trough is forecast to move across the region late
Tuesday into Wednesday, bringing the next chance (40-65%) for
showers and thunderstorms. Instability appears modest with this
mid-week feature, keeping severe probabilities low.

Temperatures...Temps this weekend will dip a little below normal
as northwest flow prevails, with highs mainly in the 70s to near
80 (with a few upper 60s over far northern WI on Sunday). A couple
chilly nights are in store this weekend, especially across
northern WI where lows will dip into the upper 30s to low 40s.
Temps nudge back to near or slightly above normal for much of next
week with highs mainly in the mid 70s to low 80s.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1016 PM CDT Fri Aug 21 2026

A cold front is exiting northeast Wisconsin and over Lake
Michigan late this evening. Scattered showers and thunderstorms
will have or about to exit by TAF issuance time.

Winds will shift to the northwest as the front passes. Scattered
VFR clouds will likely persist into the overnight hours before
clearing occurs for a short time. Patchy ground fog is possible,
particularly over the northwoods (RHI).

Clouds increase on Saturday morning as an upper disturbance dives
into the region from the northwest. While sct-bkn MVFR ceilings
could move into far north-central WI after 10Z, expect low end VFR clouds
to build with daytime heating in the 15-16Z timeframe. Expect
scattered showers and isolated storms to develop over northeast WI
in the 19-23Z timeframe which could impact GRB/MTW so added a
prob30 group consequently. ATW is on the western edge of the
shower potential, but will continue to monitor trends.

Northwest winds will be a bit breezy on Saturday with gusts to 20
kts at all terminals.

Clearing skies are anticipated after 00z Sun.

&&

.MARINE...
Issued at 126 AM CDT Sat Aug 22 2026

Northwest winds of 10-20 kts are expected this weekend. Gusts to
25 kts will be possible, mainly near Death`s Door. HREF 10m gust
ensemble mean and max bring 25 kt winds right to Washington
Island, but keep the stronger winds towards northern Lake
Michigan. Due to the very small area and marginal winds, will hold
off on issuing a Small Craft Advisory.

Offshore winds will limit waves to 1 to 3 ft for most spots on the
bay and nearshore waters, with any 3-4 foot waves staying in the
open waters.

&&

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

&&

$$

DISCUSSION.....Bersch
AVIATION.......MPC
MARINE.........Bersch

NWS GRB Office Area Forecast Discussion