Area Forecast Discussion
Issued by NWS Green Bay, WI

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192
FXUS63 KGRB 242345
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
545 PM CST Tue Jan 24 2017

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Wednesday
Issued at 244 PM CST Tue Jan 24 2017

Main focus for this period will the system moving across the
region later tonight and Wednesday. Already delayed the start
of the winter weather advisory by a few hours based on the latest
meso models which don`t have the precipitation arriving until
around 06z in our southwest counties. There may be some
drizzle or freezing drizzle before, changing to snow across
central and east-central Wisconsin. The change over to snow
across the far north may not occur until late tonight or Wednesday
morning.

The system is expected to pass south of the area on Wednesday.
Most of the precipitation should be in the form of snow. Maybe
a little freezing drizzle early far north with drizzle during the
rest of the day. Temperatures across central and east-central
Wisconsin may be warm enough for light rain if precipitation
becomes light. Current headlines seems to be in good shape. May
need to watch our southwest counties as they would be approaching
warning criteria snow. With temperatures above freezing, the wet
snow will compact and probably melt some during the day Wednesday.
Total snowfall amounts of less than an inch is expected over the
far north, 1 to 3 inches from Rhinelander and Merrill east to
Marinette and northern Door Counties, and 4 to 7 inches south of
a Wausau to Sturgeon Bay line with the highest totals near Wautoma
and Wisconsin Rapids. Only minor changes made to the max/min
temperatures. Did go lower than guidance for highs on Wednesday
due to precipitation in the area.

.LONG TERM...Wednesday Night Through Tuesday
Issued at 244 PM CST Tue Jan 24 2017

Focus in the long term begins with the ongoing system Wednesday
evening into early Thursday. With the overall timing of the
system slowing down in recent model runs decision was made to
extend the Winter Weather Advisory until 06Z for the southern
counties. Most models show pcpn in this area through 06Z. GFS and
ECMWF still showing QPF in the southeast through 12Z Thursday
before pulling east. Raised PoPs in this area to reflect the
change and slower timing. Going with mainly snow as the dominate
precipitation type during this time; however, model soundings do
indicate some loss of ice crystals aloft. Kept mention of some
mixed precip/freezing drizzle, especially towards the north where
the drier air arrives first.

Northwest flow behind this system allows for a cooler airmass to
advect into the area. High temperatures expected to get closer to
seasonal normals by Friday, with low temperatures still about 10
to 15 degrees above normal through early next week.

The main influence of this pattern shift will be the cooler
northwest winds and the potential for lake effect snow in north
central Wisconsin through the weekend. Low levels winds look
somewhat favorable Thursday afternoon into Friday when the low
pressure pulls east. Winds may back too far west Friday afternoon
to get any substantial snow in Vilas County. Right now only minor
accumulations look to occur through Friday. Trajectories show
signs of veering to a more favorable NNW direction on Saturday
which may allow for a better accumulating snow in the north
central Wisconsin snow belt region.

Early next week, GFS, ECMWF, and Canadian models all show an area
of low pressure moving along the southern Canadian border. Trailing
cold front could trigger off some snow across the area during the
Tuesday/Wednesday time frame. With temperatures closer to normal
by this point precipitation type does not look to be a concern.
&&

.AVIATION...for 00Z TAF Issuance
Issued at 545 PM CST Tue Jan 24 2017

A solid MVFR deck has settled in across the region this evening.
Cigs will continue to lower tonight to IFR with some drizzle
developing ahead of an approaching low pressure system. Snow
should arrive around 06z at KISW/KMFI/KY50/KOSH. The snow should
arrive around 08z for KAUW/KCWA/KGRB/KMTW/KATW. Snow will continue
through much of the remainder of the night into Wednesday evening,
before tapering off to drizzle or ending.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from midnight tonight to midnight CST
Wednesday night for WIZ045-048.

Winter Weather Advisory from 2 AM Wednesday to midnight CST
Wednesday night for WIZ038>040-049-050.

Winter Weather Advisory from 2 AM to 6 PM CST Wednesday for
WIZ030-031-037.

Winter Weather Advisory from midnight tonight to 6 PM CST
Wednesday for WIZ035-036.
&&

$$

SHORT TERM.....Eckberg
LONG TERM......KLB
AVIATION.......Kurimski



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