256
FXUS63 KGRB 012301
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
601 PM CDT Thu Oct 1 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Areas of frost possible at times across northern Wisconsin into
  early next week. Greatest chances for a widespread frost and/or
  freeze late Friday night and late Sunday night.

- Mainly dry through the middle of next week, with the lone
  exception a 30-50% chance of rain showers for northern WI late
  Saturday through Saturday night.

&&

.DISCUSSION...
Issued at 113 PM CDT Thu Oct 1 2026

Rain slowly ending over eastern WI this afternoon. A few spots
have reached 0.50 inch of rain, but most locations have stayed
well under 0.25 inch. No rain over north-central and far northeast
WI, where it is desperately needed. Chances of rain moving
forward will be few and far between. Shortwave trough and
associated sfc low zips across the upper Great Lakes Saturday
night. An isolated light shower could form as early as Saturday
afternoon, but greatest chances (30-50%) will occur Saturday
night. Light QPF expected with only 10-15% chance of seeing
anything more than 0.25 inch. Next chance of rain, showing up more
in the deterministic models versus ensembles does not arrive
until next Wednesday. High pressure will be the primary weather
feature around through that time.

Temperatures/Frost: Main impact in the weather will be cooler
temps and frost/freeze potential. Risk starts up as early as
tonight. Better chances, by far, set up for Friday night into
early Saturday, then again Sunday night into early Monday. NBM
probabilities of seeing temps less than 33F surge to 50-90% mainly
from Rhinelander to Marinette northward. When raising the temp
threshold up to lower than 36, the risk for frost expands into
central WI (30-60%) Sunday night into early Monday. Possible that
frost risk could even expand toward the Fox Valley this time as
well, and late Monday night into Tuesday morning as the high
center drifts overhead. Headlines will be needed as we have not
stopped the Frost/Freeze program yet for the season.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 600 PM CDT Thu Oct 1 2026

Scattered to broken low clouds above 3 kft will linger over KGRB
and KATW through 01-02Z and Manitowoc through 04-05Z this evening.
Mid and high clouds remain widespread across the region late this
afternoon and will take until late tonight to finally clear the
area. As northwest winds bring in colder air aloft, a few lake
clouds could move into KRHI between 07-14Z but confidence is low.

Mainly clear skies on Friday except for few to sct fair weather
clouds over far northern WI.

Northwest winds 5-10 kts will remain relatively steady through the
TAF period.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......MPC

NWS GRB Office Area Forecast Discussion