NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 091139
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
639 AM CDT Mon Mar 9 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Warm and breezy this afternoon, with highs reaching well into
  the 60s in central, northewast and east central WI. Record highs
  may be surpassed in several locations.

- Windy with a mix of rain, freezing rain, sleet and snow
  developing Tuesday into Tuesday night, changing to all snow on
  Wednesday. Snow and ice accumulations are likely. Hazardous
  travel Tuesday night into Wednesday.

- Windy with rain and snow Thursday night into Friday. Snow
  accumulations possible. Another potentially impactful wintry
  system arrives later in the weekend.

- Runoff from recent rainfall and warmer temperatures may result
  in ice break-up on rivers and localized ice jam and river
  flooding into early this week.

&&

.DISCUSSION...
Issued at 210 AM CDT Mon Mar 9 2026

A strong clipper system was moving through southwest Ontario early
this morning, with a cold front extending southwest into MN. This
system was bringing scattered thunderstorms to the MN Arrowhead
and western Lake Superior. Ahead of the front, southwest winds
gusting to 20 to 25 mph were keeping surface temperatures in the
middle 40s to middle 50s range.

A dry cold front will move through the forecast area today.
Compressional heating ahead of this boundary should boost high
temperatures well into the 60s over the southeast half of the
forecast area. Several climate sites are expected to set new
records (see the climate section below). Farther northwest, high
temperatures will be in the upper 40s and 50s. Gusty southwest
winds will become northwest in the wake of the frontal passage.

A strong low pressure system over KS Tuesday morning is expected
to track toward southern Lake Michigan by Tuesday evening, then to
far southeast Ontario by Wednesday evening. This track keeps the
forecast area on the cold side of the system, with potential for
rain, freezing rain, sleet and snow changing to all snow on
Wednesday. Probabilistic forecasts show a 40 to 70 percent chance
of 2+ inches of snow over north central and northeast WI, and a 40
to 60 percent chance of ice accumulations over the southern two-
thirds of the forecast area Tuesday night into Wednesday morning.
This system will likely generate strong NE winds in the Fox
Valley/lakeshore areas Tuesday into Tuesday night, followed by
gusty NNW winds Wednesday into Wednesday night. NBM probabilities
for gale force gusts on Lake Michigan have dropped to 20 to 40
percent. All of this leads to growing potential for Winter Weather
Advisories (for snow in the far north and a wintry mix/ice
accumulations farther south). Will monitor trends for possible
Gale Warnings too.

A strong clipper system is expected to pass through WI Thursday
night into Friday, bringing another round of strong winds,
potential gales on Lake Michigan (50-70%) and accumulating snow
(40-70% chance of 2+ inches and 30-50% chance of 4+ inches over
northern WI).

Another potentially impactful low pressure system approaches
later in the weekend. Model differences are significant this far
out, but significant snowfall accumulations appear plausible with
this system.

Ice Jam/Ice Floe Potential...Runoff from recent rain and
continued mild temperatures will increase the threat of ice break-
up early this week. This will result in susceptible rivers rising
to bankfull or even minor flood stage.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 631 AM CDT Mon Mar 9 2026

Strong LLWS will end across the region by mid to late morning.
Gusty southwest surface winds will veer W-NW as a cold front moves
through, then become NE later this afternoon into tonight. The NE
winds will become gusty in the Fox Valley/lakeshore areas
tonight.

The cold front will move through dry today. A band of light snow
may develop across far northern WI late tonight, but should remain
north of RHI. A couple bands of lower clouds could impact the
region. The first, which was moving through the MN Arrowhead,
could brush into far north central WI this morning before eroding.
A second area is expected to move into the region during the late
evening and overnight hours. MVFR ceilings may develop in some
areas later tonight, especially in NC WI.

&&

.CLIMATE...
Issued at 210 AM CDT Mon Mar 9 2026

Record highs are in jeopardy of being broken on Monday, March 9.
Here are the current record high temps and forecast highs:

Antigo: 52 in 1930,1966,2025 (forecast 55)
Appleton: 61 in 2021,2025 (forecast 64)
Green Bay: 60 in 2025 (forecast 64)
Manitowoc: 60 in 2025 (forecast 59)
Marshfield: 62 in 2021 (forecast 60)
Merrill: 60 in 1977 (forecast 55)
Oshkosh: 68 in 1956 (forecast 63)
Rhinelander: 57 in 1977 (forecast 52)
Stevens Point: 63 in 1987 (forecast 62)
Sturgeon Bay: 55 in 2025 (forecast 57)
Wausau: 60 in 2021 (forecast 59)
Wisconsin Rapids: 68 in 1987 (forecast 64).

&&

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

&&

$$

DISCUSSION.....Kieckbusch
AVIATION.......Kieckbusch
CLIMATE........Kieckbusch