Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 041628
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1028 AM CST Sun Dec 4 2016

New Information added to update section

.UPDATE...
Issued at 1016 AM CST Sun Dec 4 2016

Light to moderate snowfall continues to overspread the area ahead
of a shortwave trough now moving into the northern Mississippi
Valley. Some of the coldest cloud tops are moving northeast from
eastern Iowa and heading for northeast Wisconsin. Based on these
trends and short-term guidance, have expanded the winter weather
advisory a row of counties north into north-central Wisconsin and
also Door County, where 3 to 4 inches of accumulations are now
expected. Some uncertainty in snowfall amounts remains along the
lakeshore, mostly due to a developing south wind and its impact on
temperatures this afternoon. Temps aloft look cold enough for
mainly snow, except right near the lakeshore. So think Kewaunee
and Door counties will fair well with accumulations. Also changed
the ending time of the advisory until 03z tonight for far
northeast Wisconsin, since another inch of accumulations will be
possible after 00z.

&&

.SHORT TERM...Today...Tonight...and Monday
Issued at 300 AM CST Sun Dec 4 2016

Light snow was moving into western Wisconsin as of 08Z, ahead of
a mid level trough that was over the Plains. As the trough moves
into the Great Lakes Region today, snow timing and amounts are
the main forecast concerns.

The 00Z GRB sounding revealed plenty of dry air with the exception
the 900mb-850mb layer that was just below a strong inversion. The
DVN and MPX soundings were not as dry. Moisture is expected to
deepen enough overnight to possibly bring a dusting of snow to
central Wisconsin by 12Z. Snow will spread across the forecast
area during the morning and continue this afternoon.

Think that totals should be in the 2 to 4 inch range across central
and parts of east central Wisconsin today, with the highest totals
in central Wisconsin. It should be slightly warmer farther east,
with highs above freezing, which could melt some of the snow
resulting in lower totals. Even warmer air along Lake Michigan
shoreline should keep snow amounts even lower there.

There could be up to an inch of accumulation during the evening
before this system departs, generally in the far northeast part of
the area. Dry conditions should prevail after midnight and through
Monday. Clouds will keep temperatures from dropping much during
the night.

.LONG TERM...Monday Night Through Saturday
Issued at 300 AM CST Sun Dec 4 2016

A low pressure system over the northern Midwest will strengthen
as it drifts northeast into Canada toward Hudson Bay. The low will
pull cold air south from Canada into Wisconsin. Temperatures will
drop to at or below normal for this time of year starting
Wednesday and continuing through next weekend. Normal high
temperatures are around 30 in the Fox River Valley region and mid
to upper 20s for northern Wisconsin. Normal lows range from around
15 degrees in the Fox Valley to around 10 degrees in northern
Wisconsin.

For the work week, there is a slight chance for light snow across
the area on Tuesday, but moisture will be limited and snowfall
accumulation should generally be under an inch. Starting
Wednesday, moisture from Lake Superior will fuel periodic lake
effect snows over far northern Wisconsin for several days starting
Wednesday.
&&

.AVIATION...for 12Z TAF Issuance
Issued at 537 AM CST Sun Dec 4 2016

Ceilings were mainly VFR in eastern Wisconsin and MVFR across
the central and north central parts of the state. MFI had IFR
visibility with light snow at 11Z. Expect MVFR, then IFR, ceilings
to spread across the area along with the snow during the morning
hours. Snow will also reduce visibility to IFR, and at times
LIFR. The snow should end during the evening, so visibility should
improve but the low ceilings will remain. Expect some improvement
to MVFR during the overnight hours across central and parts of
east central Wisconsin.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM CST this evening FOR
WIZ018>020-030-031-035>038-045-048-049.

Winter Weather Advisory until 9 PM CST this evening FOR WIZ022-
039-040-050-074.
&&

$$

UPDATE.........MPC
SHORT TERM.....MG
LONG TERM......ML
AVIATION.......MG


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