Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 071058

Area Forecast Discussion
National Weather Service Green Bay WI
458 AM CST Thu Dec 7 2023

Updated aviation portion for 12Z TAF issuance

- Warmer temperatures are expected today, and well above normal
  temps (10-20 degrees), but below records, remain likely on

- Although considerable uncertainty remains, probabilities are
  slowly rising (20-40%) of greater than 2 inches of snowfall on
  Saturday over north-central Wisconsin.

- Precipitation will consist of mainly rain over the Fox Valley
  and northeast Wisconsin on Saturday. An isolated rumble of
  thunder is also possible.


Issued at 254 AM CST Thu Dec 7 2023

SHORT TERM...Today...Tonight...and Friday

Wisconsin will be located between high pressure over the
southeast United States and a developing low pressure which will
move into the Dakotas today. As south winds strengthen, a warm
front will be lifting northeast across northern Wisconsin. Surface
to 800mb dewpoint depressions remain quite large (5 to 10C) so no
precip is expected with the warm front. But temps will be quite a
bit warmer today under partly cloudy to mostly sunny skies with
highs in the low to middle 40s.

Gulf moisture will surge into the region tonight, which will
likely lead to a low stratus deck developing after midnight into
Friday morning. Because of south winds and low stratus, raised low
temps compared to the previous forecast.

Forecast soundings indicate that the low stratus will mix out with
daytime heating by mid to late Friday morning, which should lead
to plenty of sunshine, although mid and high clouds will increase
some in the afternoon. Mixing heights remain low, perhaps up to
1500 ft above ground level, so warm temps aloft will struggle to
mix to the surface. But breezy south winds should bring temps into
the mid 40s to low 50s.

LONG TERM...Friday Night Through Wednesday

The primary weather concern will occur on Saturday when a fast-
moving low pressure system will sweep up from the south and
deliver wet, windy weather. Computer models vary considerably on
the track of the low, which will play a big role in how much
wintry precipitation falls and for what portion of our region.
From an areal perspective, if the ensemble track forecast holds
true, substantial snowfall rates could be achieved in some areas,
with perhaps 10 percent coverage of greater than 3 inches of
snowfall in northern WI on Saturday. However, there is a wide
range of possibilities with this dynamic system. Forecast
confidence is at least moderately high with timing of the system
occuring on Saturday. A secondary shortwave has potential to
deliver an inch of snow to a large portion of our area on Sunday.


.AVIATION...for 12Z TAF Issuance
Issued at 458 AM CST Thu Dec 7 2023

Relatively quiet weather is expected until late in the taf period.
Light winds and VFR ceilings will prevail through 06z Friday.

Models indicate that gulf moisture will return from south to north
after midnight. Sufficiently strong winds in the boundary layer
will likely result in this moisture manifesting as low stratus.
Kept ceilings in the IFR range, though guidance indicates lower
ceilings are possible. MVFR visibilities will also be possible
late tonight.

Lastly, winds are marginal for low level wind shear after midnight
across central and east-central Wisconsin.





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