800
FXUS63 KGRB 081110
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
610 AM CDT Tue Sep 8 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Rain and storms chances (60-80%) early this morning through late
  late tonight. A few strong storms are possible this morning and
  again this evening and night.

- Gusty winds and high waves today through Wednesday will result
  in hazardous conditions to small craft. There will also be an
  increased risk of rip currents at Lake Michigan beaches Tuesday
  into Wednesday morning.

- Temperatures at or above normal continue into the weekend.

&&

.DISCUSSION...
Issued at 1247 AM CDT Tue Sep 8 2026

Storm Chances Today/Tonight: A strong 40-45kt LLJ has developed over
over the central and northern Plains early this morning spurring on
scattered storms across central MN into far western WI. As the LLJ
shifts east early this morning storms will push into central and
north-central WI. There is enough (250-500 J/kg) elevated
instability for these storms to continue producing lightning as well
as sporadic strong wind gusts and hail through the morning. Storm
activity will gradually decrease late morning and afternoon as the
LLJ weakens, however, CAMs do show some isolated storms percolating
through much of the day as return flow brings a narrow ribbon of
moist and weakly unstable air into the region. Another uptick in
storm activity is expected this evening/overnight as a cold front
swings across the region. There is a marginal (1/5) risk for strong
to severe storms along and just ahead of the front despite rather
unimpressive thermal profiles as a seasonally strong 40-50kt 500mb
jet overspreads the region. One aspect to monitor with any storms
will be high rainfall rates as PWATs are expected to near 2" and
warm cloud depths of 10-12kft will promote efficient warm rain
processes. Storm motions will not be overly slow, so any flood
threat may mainly be tied to any training storms.

Along with the storm chances today expect breezy south winds with a
tightening pressure gradient. There is a 30-50% chance for peak wind
gusts over 30 mph across northern WI while areas in central and east-
central WI may see wind gusts peak around 20-25 mph this afternoon.

Rest of the Forecast: A few isolated showers may linger through
early Wednesday morning as the aforementioned front pushes east of
the region. Dry conditions are then forecast for the remainder of
Wednesday through much of Friday. Following the frontal passage , a
tight pressure gradient will develop on Wednesday leading to gusty
westerly winds of 30-35 mph. The next chance of showers and storms
arrives Friday night into Saturday with a cold frontal passage.
Confidence is low on timing and placement of convection. Aside from
near normal temperatures on Thursday, but temperatures will remain
above normal.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 610 AM CDT Tue Sep 8 2026

Widespread area of rain has spread across central and norht-central
WI early this morning and will continue to expand across the region
through mid-morning with isolated embedded thunderstorms at times.
Withing the steadiest rain across central WI vsbys have been falling
as low as 1 1/2SM while most sites are reporting 4-5SM. Rain shower
gradually dry up late this morning and afternoon leaving mainly VFR
conditions, except across northern WI there MVFR cigs may develop
behind the rain. A second period of showers/storms is possible late
this evening, after 03Z, as a cold front passes the region. There is
uncertain with the timing and intensity of any storms along the front
so for now have framed out the best timing with PROB30 groups at all
TAF sites. Behind the cold front a blanket of IFR status is expected
to develop Wednesday morning across much of the region.

Southerly winds ramp up ahead of an approaching cold front this
afternoon. Prevailing winds will be around 10 to 15 knots, with
gusts to 20 knots at all sites. Locally higher gusts may be possible
near MTW.

&&

.MARINE...
Issued at 1247 AM CDT Tue Sep 8 2026

Southerly winds will increase today and result in high waves on the
nearshore waters of Lake Michigan and northern Green Bay. A lull in
the winds is expected early Wednesday morning, before increasing
again and veering west late Wednesday morning. Conditions will be
hazardous to small craft during these times. There will also be an
increased risk of rip currents mainly Tuesday into Wednesday
morning, until winds turn offshore. Small Craft Advisories and Beach
Hazards Statements are in effect through 7AM Wednesday. Another
Small Craft Advisory will be needed for Wednesday afternoon/evening,
once the westerly winds increase.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from 1 PM CDT this afternoon through
Wednesday morning for WIZ022-040-050.
&&

$$

DISCUSSION.....GK
AVIATION.......GK
MARINE.........GK

NWS GRB Office Area Forecast Discussion