Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 220138

Area Forecast Discussion
National Weather Service Green Bay WI
738 PM CST Tue Nov 21 2017

New Information added to update section

Issued at 732 PM CST Tue Nov 21 2017

Updated to add a mention of freezing drizzle over north central
and northeast WI Wednesday night. BUFKIT soundings indicate
potential for a brief period of light snow or flurries, followed
by a few hours of freezing drizzle as mid-level moisture erodes.
With the potential for early holiday travel, opted to update now
and put a mention of freezing drizzle and slick roads in the
Hazardous Weather Outlook. Snowfall should be a dusting to a half
inch, with only a light glaze of ice anticipated.


.SHORT TERM...Tonight and Wednesday
Issued at 235 PM CST Tue Nov 21 2017

Lake effect snow showers in northern Wisconsin should dissipate
by late evening as low level winds diminish and become westerly.
Skies should clear over most of the area overnight as a surface
high moves across Wisconsin. Skies should begin as sunny
Wednesday, but high clouds will arrive in the afternoon ahead of a
weakening clipper system. Lows tonight and highs Wednesday will
be 5 to 10 degrees below normal.

.LONG TERM...Wednesday Night Through Tuesday
Issued at 235 PM CST Tue Nov 21 2017

Various systems passing by in the northwest flow aloft will
provide a few chances of precipitation and fluctuating
temperatures for much of the period. Cold air on northwest winds
at times will produce periods of lake effect snows far north.

A quick moving clipper system with frontal system will be passing
over the region Wednesday night. System will be moisture starved
but a few snow showers or flurries will be possible along or near
the fropa. At this time a dusting of snow cover is possible late
Wednesday night. If accumulation trends increase, then a mention
in the HWO will be needed.  High pressure to quickly slide over
Thursday with return flow already developing toward Thursday night
and continuing into Friday morning.

Next more robust clipper or shortwave trough to drop over the
area later Friday into Saturday morning. Air mass will be warm
enough at the start for mainly rain but colder air advecting into
the region behind the system will turn the pcpn type to a mix
and to mainly snow north. System precipitation departs rather
quickly before colder air arrives, so snow amounts appear limited.
Winds will be rather strong with this system.

Rest of the weekend will be breezy and cold before another warming
trend for the start of the new work week ahead of another system.

.AVIATION...for 00Z TAF Issuance
Issued at 529 PM CST Tue Nov 21 2017

VFR ceilings between 3500 and 4000 feet should erode in northeast
and east central WI early this evening. MVFR ceilings and
scattered lake effect snow showers or flurries will probably
persist over north central WI past midnight, then decrease as
high pressure builds in and causes winds to turn west.

Mostly clear skies should prevail late tonight through mid-
afternoon Wednesday, then mid-level clouds will arrive ahead of a
weak clipper system. This system may produce a few hours of light
snow or light freezing rain Wednesday night.



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