609
FXUS63 KGRB 110339
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
939 PM CST Sat Jan 10 2026

Updated aviation portion for 06Z TAF issuance

.UPDATE...
Issued at 841 PM CST Sat Jan 10 2026

The forecast is mostly on track this evening. Double-barreled
upper low is spinning over Wisconsin and northern Lake Michigan.
Meanwhile, a low level trough extends west from a surface low
east of Georgian Bay to the western Upper Peninsula.

A band of intense of intense snow continues along this trough,
augmented by 900-700mb fgen. Visibilities have ticked up over the
past hour after a several hour period of 1/4-1/2sm visibilities
from Iron Mountain to Washington Island. A report from Menominee
County, Michigan showed 7.5" has fallen and believe that is a
decent comp for northern Door county.

This band has started the return south over the past hour and
should approach the northern Fox Valley around 11 PM or so.
Guidance generally shows the band weakening as it heads south.
Areas within this band may see up to an additional inch from
Florence to Door County. As it moves across east-central WI,
a half inch to an inch is possible, but more likely on the lower
end of this range.

Winter Weather Advisories and Warnings continue this evening,
though early cancellations seem probable.

&&

.KEY MESSAGES...

- Significant accumulating snow and hazardous travel conditions
  will continue across far northeast Wisconsin into tonight.
  Winter Weather Advisories remain in effect for Florence and
  Marinette counties, with a Winter Storm Warning for Door County.
  Additional light snow will occur across the rest of the
  forecast area, but accumulations should be light and generally
  under an inch.

- There is a chance of light snow accumulations across northern
  Wisconsin Sunday night.

- Light mixed precipitation is expected late Monday night into
  Tuesday night, with accumulating lake-effect snow expected in
  north central Wisconsin late Tuesday night into Wednesday.

- Temperatures will rebound to above normal early next week, then
  fall again into midweek.

&&

.DISCUSSION...
Issued at 245 PM CST Sat Jan 10 2026

A band of moderate snow had shifted northeast this afternoon,
and was situated across Florence, Marinette and Door County
at 2 pm. Snowfall reports have been spotty during the day, but
most reports in the headline areas indicated 2 to 3 inches.
Clearing occurred over the southwest part of the forecast area
after the snow band moved east, but low clouds and numerous light
snow showers were approaching north central and central WI, in
association with an upper low.

The snow band is expected to pivot WNW to ESE across far northeast
WI, then drop south through the region and gradually weaken later
this evening and overnight. Most of the impacts with this should
be felt across eastern WI, with continued significant
accumulations occurring in Florence, Marinette and Door counties
through midnight, and lesser amounts up to an inch across the rest
of eastern WI. The snow showers associated with the upper low
will be most numerous over the southwest part of the area into the
early evening, but patchy light snow showers or flurries could
persist into the overnight period. Clearing is expected across all
but north central WI Sunday morning, but this will short-lived,
as clouds will increase ahead of a clipper system later in the
afternoon.

Rest of the Forecast... A weak clipper system will brush through
northern WI Sunday night, and could bring light accumulations and
slippery roads there. A second stronger clipper arrives late
Monday night, bringing light mixed precipitation through Tuesday
night. Accumulating lake-effect snow is expected over north
central WI late Tuesday night into Wednesday. Additional chances
for light snow arrive Thursday night into Friday, and last into
the weekend, but no big storms are anticipated and details remain
sketchy this far out.

Temperatures will warm to above normal again early next week. A
decent surge of colder air and gusty north winds follows the
midweek clipper system, leading to cooler temperatures for the
latter half of the work week.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 939 PM CST Sat Jan 10 2026

A band of moderate snow will drop south across eastern WI late
this evening into early overnight. This band of snow will be
weakening but could still drop visibilities to IFR briefly at
GRB/MTW in the 04-07Z timeframe. Light snow will still impact the
other terminals with MVFR ceilings and visibilities
predominately. Flurries will likely linger after the band of snow
exits until late tonight.

Low- level wind shear remains a concern overnight as a 35-40 kts
develops around 2,000 ft AGL.

Drier air arriving from the northwest will lead to clearing and a
return to VFR for most sites by 14Z-17Z Sunday. MVFR ceilings
will likely persist longest at KRHI due to lake-effect clouds.
West to northwest winds will remain gusty through much of the TAF
period with gusts peaking 20 to 25 kts.

Light snow may redevelop (30-40% chance) over far northern WI
(RHI) on Sunday evening along with low level wind shear.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight CST tonight for WIZ012-
013-073.

Winter Storm Warning until 3 AM CST Sunday for WIZ022.
&&

$$

UPDATE.........MPC
DISCUSSION.....Kieckbusch
AVIATION.......MPC

NWS GRB Office Area Forecast Discussion