Area Forecast Discussion
Issued by NWS Green Bay, WI

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962
FXUS63 KGRB 201151
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
551 AM CST Tue Feb 20 2018

Updated aviation portion for 12Z TAF issuance

.SHORT TERM...Today...Tonight...and Wednesday
Issued at 351 AM CST Tue Feb 20 2018

Low pressure moving slowly across the state will produce one more
round of significant precipitation this morning, and it will arrive
right when most people are going to school or work. Ice accumulations
of one to two tenths are not out of the question across central
Wisconsin with less to the north and east. Some elevated thunderstorms
are possible south of highway 10. The precipitation could change
briefly heavy snow if the convection makes it this far north. The
precipitation should taper off or end by midday over all but east
central Wisconsin.

Highs today will range from the upper 20s in the far north to the
40s south of east of Green Bay as mild air moves north as winds
shift to the southwest as the surface system passes by to the west
of the Fox Valley. Shortened the duration of the advisory in east
central Wisconsin already, and next shift may be able to end it by
midday.

Colder and drier air will arrive tonight and Wednesday as a
surface high moves into the Midwest. Temperatures will be near
or a little below normal.

.LONG TERM...Wednesday Night Through Monday
Issued at 351 AM CST Tue Feb 20 2018

Upper level flow is expected to be mainly out of the southwest
during this part of the forecast, resulting in above normal
temperatures and some issues with precipitation timing and type.

Surface high pressure should help to keep the area dry Wednesday
night, but there is a slight chance for snow in parts of central
and north central Wisconsin Thursday afternoon in an area of warm
advection ahead of an approaching mid level short wave. Snow
spreads across the entire area Thursday night, but there could be
some freezing or mixed precipitation in the southern part of the
forecast area. Precipitation should exit by midday on Friday but
will change to liquid or a wintry mix as temperatures warm. Dry
weather is in store for Friday afternoon through Saturday morning
as the next surface high passes across the region. There is a
chance for rain or snow across much of the area Saturday afternoon
ahead of a strengthening surface low and mid level trough. The
00Z GFS had a stronger surface and upper system than either the
00Z ECMWF or Canadian, and it kept precipitation in the area
longer. There should be a break in the action Sunday afternoon
through Sunday night, followed by another chance for rain and/or
snow on Monday with the next system.
&&

.AVIATION...for 12Z TAF Issuance
Issued at 551 AM CST Tue Feb 20 2018

Poor flying weather and challenging airport conditions expected
this morning as freezing rain and sleet move across the region as
low pressure moves northeast across the state. Deicing will be
needed for aircraft and pavement through middle to late morning.
The precipitation will diminish or end by afternoon in most
places. Temperatures will warm above freezing by afternoon east of
a Stevens Point to Marinette line. Temperatures will stay near or
below freezing further west. FLying conditions will improve this
afternoon and become VFR by tonight.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 3 PM CST this afternoon for WIZ005-
038>040-045-048>050.

Winter Weather Advisory until 6 PM CST this evening for
WIZ010>013-018>022-030-031-035>037-073-074.
&&

$$

SHORT TERM.....RDM
LONG TERM......MG
AVIATION.......RDM



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