405
FXUS63 KGRB 020621
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
121 AM CDT Sun Aug 2 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- There is an increased risk for rip currents along Lake Michigan
  beaches in Kewaunee and Manitowoc counties today.

- Relatively quiet weather expected through Monday night.

- Isolated to scattered showers and thunderstorms return Tuesday
  and Wednesday as a cold front moves through the region.

&&

.DISCUSSION...
Issued at 121 AM CDT Sun Aug 2 2026

Increasing northeast winds on a tightening pressure gradient have
advected in an MVFR stratus deck across much of northeast,
central, and east-central Wisconsin early this morning. These
low ceilings are expected to gradually lift into a
stratocumulus/cumulus field by late this morning as diurnal
heating and dry air advection take hold. Skies should then clear
from north to south this afternoon as strong surface high pressure
builds south out of Ontario. High temperatures today will be
somewhat suppressed by the low clouds and onshore flow, ranging
from the mid 70s near Lake Michigan to around 80 degrees across
central Wisconsin.

High pressure will center over the western Great Lakes tonight
through Monday night, bringing a period of quiet and pleasant
weather with near-normal temperatures and comfortable humidity.
Highs on Monday will reach the upper 70s to mid 80s under mostly
sunny skies.

The next weather maker approaches Tuesday as a shortwave trough
and associated surface cold front track eastward across the Upper
Midwest. Convective parameters ahead of the boundary appear
modest, with MUCAPE values peaking around 500 to 1000 J/kg and
deep-layer shear around 25 to 30 knots. This combination suggests
a minimal threat for organized severe weather. However,
precipitable water values rising to 120 to 130% of normal
alongside deep-layer flow aligned parallel to the surface frontal
boundary could promote localized training of showers and storms,
presenting a low risk for localized heavy rainfall. Recent model
runs are a bit drier with the initial showers and thunderstorms,
particularly across east-central Wisconsin. In fact, there is a
possibility most of these areas could remain mostly dry until late
Tuesday night when the main low lifts out of the southern Plains
and an area of mid level frontogenesis develops across the western
Great Lakes.

Most global ensemble guidance rapidly pushes the cold front east
of the area by Wednesday morning, though lingering light rain
showers cannot be ruled out over northeast Wisconsin early
Wednesday. A notable outlier in deterministic guidance (GFS)
holds the front up and delays its eastern progression,
maintaining heavy rainfall potential into Wednesday, but this
solution lacks support from ensemble cluster means. High pressure
builds back into the Upper Mississippi Valley behind the front
for Wednesday and Thursday, returning dry weather and seasonal
conditions. The next upper-level shortwave and cold front will
bring the next opportunity for showers and thunderstorms toward
next Friday into Saturday. Temperatures throughout the 7-day
period will remain right around seasonal averages, with daily
highs in the mid 70s to mid 80s and overnight lows in the upper
40s to low 60s.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1100 PM CDT Sat Aug 1 2026

MVFR cigs moved into central and east-central WI late this
evening, while mostly clear skies prevailed in north-central WI.
A few showers also lingered in portions of east-central WI late
this evening but all terminals are expected to remain dry.

Northeasterly winds will continue to funnel low-level moisture
into the area keeping the MVFR cigs across the east-central WI TAF
sites and into the central WI TAF sites at times. Confidence is
lower for the MVFR cigs reaching the RHI TAF site. Cigs may
briefing drop to IFR at the east-central WI TAF sites late tonight
into early Sunday morning. The MVFR cigs should lift into a SCT
cumulus field by late Sunday morning and eventually clearing out
by Sunday evening.

Northeast winds are expected through this TAF period generally
under 10 kts, however, gusts to 15 to 20 kts are anticipated at
the east-central WI TAF sites through late Sunday afternoon. Winds
will become light and variable by late Sunday evening.

&&

.MARINE...
Issued at 121 AM CDT Sun Aug 2 2026

The persistent northeast fetch will also create hazardous
conditions for mariners on Lake Michigan, with winds increasing to
15 to 25 knots and waves building to 3 to 5 feet today. With
winds and waves expected to increase today, hazardous conditions
are expected south of Sturgeon Bay.

As for headlines, kept the small craft advisory between Sturgeon
Bay and Two Rivers starting at 6 AM. The Beach Hazard Statement
and Small Craft Advisory adjacent to the Manitowoc shoreline will
continue as well.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from 6 AM CDT this morning through this
evening for WIZ050.
&&

$$

DISCUSSION.....Kurimski
AVIATION.......Kruk
MARINE.........Kurimski

NWS GRB Office Area Forecast Discussion