Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 141810

Area Forecast Discussion
National Weather Service Green Bay WI
1210 PM CST Thu Dec 14 2017

Updated aviation portion for 18Z TAF issuance

.SHORT TERM...Today...Tonight...and Friday
Issued at 333 AM CST Thu Dec 14 2017

Cyclonic upper flow and cold air blowing over Lake Superior will
produce lake effect clouds and snow showers and flurries today,
especially across northcentral Wisconsin. There should be some
sunshine at times across the eastern part of the state. Highs will
be 5 to 10 degrees below normal.

The left exit region of an upper jet will move across the region
tonight. This will result in upper level diffluence and weak low
level warm advection. The atmosphere is relatively dry, but a
dusting to an inch of snow is possible, especially north of
highway 29.

Friday should be blustery and cold with lots of clouds and some
lake effect snow showers in cyclonic upper flow . Highs will be
about five degrees below normal.

.LONG TERM...Friday Night Through Wednesday
Issued at 333 AM CST Thu Dec 14 2017

500mb ridge across western North America and downstream troughing
across eastern Canada into the northern United States is expected
to flatten over the weekend. A zonal flow aloft is expected for
much of next week, keeping the bitter arctic up in Canada.

Timing of the systems through the mean flow continues to be
problematic during the forecast period. The system for Saturday
into Saturday night has been pushed up to the Friday night and
Saturday period. Per coordination with surrounding offices to the
south, have increased the chances of light snow for this period
and added up to a couple inches of snow possible. Once this
features exits the area, this next system is on it way which will
bring a small chance of light snow to northern Wisconsin Saturday
night into Sunday. Dry conditions are expected Sunday and Monday.
Dry conditions will continue Tuesday and Wednesday, except across
the far north where chances of light snow showers exist.

Temperatures will return closer to normal on Saturday, then above
normal temperatures are expected for Sunday into Tuesday.
Temperatures are then expected to return to near normal levels
on Wednesday.

.AVIATION...for 18Z TAF Issuance
Issued at 1209 PM CST Thu Dec 14 2017

A weak upper level disturbance will spread snow showers and
flurries from west to east across the area this afternoon and
evening, with another disturbance crossing the area overnight.
These will bring mainly MVFR cigs and periods of MVFR vsbys to
the area. A period of VFR conditions are expected across eastern
WI this afternoon before the lower clouds move in. Periods of IFR
conditions are possible across north central WI, impacting RHI.
The flurries and snow showers activity is expected to diminish
Friday morning, with some partial clearing.



LONG TERM......Eckberg
AVIATION.......Bersch is the U.S. government's official web portal to all federal, state and local government web resources and services.