NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 120403
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1103 PM CDT Wed Mar 11 2026

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- A few slippery spots are possible this evening from lingering
  light snow, but overall expect clearing and improved road
  conditions.

- Medium to high (30-60%) chances for at least 6 inches of snow
  across northern Wisconsin Thursday night into Friday, along
  with strong, gusty winds.

- The potential for widespread snow with moderate to major impacts
  remains consistent. There is a 60-90% chance for at least 6" of
  snow, with potential for much higher amounts. Those with weekend
  travel plans should closely monitor the weather.

&&

.DISCUSSION...
Issued at 411 PM CDT Wed Mar 11 2026

Exceptionally active spring pattern this week, with one system
exiting this afternoon, and two more on the horizon through the
rest of the week.

Light snow remains in northeast and east-central WI as of 20Z with
vsbys of 1-2SM at times. Otherwise, road impacts have been
minimal with melting occurring on contact and just wet roads for
most. Lingering snow ends in the east around sunset, followed by
clearing of the clouds (already seen in central WI). Quiet tonight
with lows in the teens to low 20s, cooler than recently.

Thursday Evening into Friday...Surface low pressure tracks from
the northern Plains midday Thursday, across northern WI Thursday
night, and through the Great Lakes Friday. This is a fast moving
clipper, but a very dynamic system with strong forcing from the
LFQ of the upper jet, mid-level shortwave, LL warm advection, and
fgen. The forcing is solidly in the DGZ leading to intense
snowfall rates around 1"/hour at times Thursday night,
particularly across northern WI where a Winter Storm Watch has
been issued. Northern WI is currently forecast to remain north
of the warm front; while south of Hwy 29 is more questionable, as
there will likely be a sharp cutoff in higher/lower snow amounts
based on exactly where the low tracks and how far north the warm
front gets. Areas along and south of the warm front will get a
wetter snow with lower snow-to-liquid ratios and rain also mixing
in.

Most snow will occur between 7PM Thurs to 7AM Friday, with new
snow winding down by the morning commute time. However, continued
snowy roads and lower vsbys are expected due to strong winds and
blowing/drifting snow. There is a 30-60% chance for wind gusts of
40mph or greater Thursday night into Friday from central to east-
central WI, and slightly lower chances farther north.

Overall, the probability for 6 inches or more of snow is still
about 40-60% across northern WI (in the Watch area), with a sharp
cutoff in percentages farther south.

Saturday Evening into Monday...The weekend system is a more
classic long-duration Colorado Low event, with the system moving
from Colorado through the central Plains Saturday-Sunday, and
tracking across lower Lake Michigan Sunday evening and northeast
from there. The combination of the strong dynamics, ample moisture
(QPF potential of 2 to 3" in spots), and the long duration of the
event have generated the potential for high snowfall amounts with
major impacts. The consensus is high that this event will occur
and impact Wisconsin, but the location of the most intense
snowfall amounts can still jog to the north or south, especially
since it is 4 to 5 days away. Right now NBM probabilities stand at
a 60-90% chance for 6"+ of snow, and 50-70% chance of 12"+ of
snow. In addition to the snow, winds will be strong leading to low
vsbys and blowing/drifting snow. Potential for 30+ mph winds is
30-50%, but this will likely increase as the event gets closer.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1102 PM CDT Wed Mar 11 2026

VFR conditions will continue overnight into Thursday afternoon,
with only some mid and high clouds moving across the area. Then
conditions will quickly deteriorate Thursday evening into Thursday
night as a strong clipper system brings accumulating snow to most
of the area. The most persistent, heaviest snow and worst flying
conditions (LIFR/IFR and possibly briefly VLIFR) will be over
northern WI, where several inches of snow is expected. Light to
moderate snow is also expected further south, mixing with some
rain at times at GRB/ATW/MTW Thursday night, dropping conditions
to IFR and possibly LIFR, but snow totals will quickly drop off
south of Hwy 29.

Northwest winds under 10 kts are expected overnight into early
Thursday morning. Winds will shift to the south and increase
Thursday afternoon, with gusts to 25 kts in the late afternoon and
evening. Some higher gusts, to around 45 kts, will be possible in
the heavier areas of precip. The gusty winds could produce some
blowing and drifting snow Thursday night. The very strong winds
above the surface (~65 kts at 5000 ft) will lead to periods of
LLWS when surface winds are not gusting.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Thursday evening through Friday
afternoon for WIZ005-010>013-018-019-021-073.
&&

$$

DISCUSSION.....KLJ
AVIATION.......Bersch