Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 201739

Area Forecast Discussion
National Weather Service Green Bay WI
1139 AM CST Tue Feb 20 2018

Updated aviation portion for 18Z 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

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 18Z TAF Issuance
Issued at 1138 AM CST Tue Feb 20 2018

Primarily LIFR conditions will continue through the afternoon as
ceilings range from about 200 to 500 feet. Fog will also reduce
visibility to 1 mile or less across parts of north- central
Wisconsin, and light rain is expected at times across the Fox
Valley and east- central Wisconsin through mid-afternoon, which at
times will lower visibilities and ceilings. This evening ceilings
should raise to MVFR heights, followed by skies becoming clear
late tonight and Wednesday morning and a return to IFR conditions.

Winter Weather Advisory until noon CST today for WIZ038>040-

Winter Weather Advisory until 3 PM CST this afternoon for WIZ005-


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