Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 150335

Area Forecast Discussion
National Weather Service Green Bay WI
1035 PM CDT Sat Oct 14 2017

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Sunday
Issued at 325 PM CDT Sat Oct 14 2017

Showers moved into the southern part of the forecast area by
1930Z, reaching most locations south of Highway 29. The showers
are expected to spread across the rest of the area during the
evening and overnight hours as a surface low passes through
Wisconsin, followed by a mid level short wave trough. So far the
lightning detection network has shown no lightning anywhere in
Wisconsin. Would not rule out thunder since there is plenty of it
in upstream in Iowa and some elevated instability was evident on
Bufkit time/height plots. Would expect heavier rainfall this
evening and tonight as well.

Showers should exit the area on Sunday with some clearing in
central and north central Wisconsin during the afternoon. The
surface pressure gradient on the back side of the departing low
is expected to be rather tight, so winds across Door County will
probably reach wind advisory criteria on Sunday.

Lows tonight should be mainly in the 40 to 50 degree range. Cold
advection behind the departing surface system will bring cooler
high temperatures on Sunday. Readings should top out in the mid
40s to lower 50s.

.LONG TERM...Sunday Night Through Saturday
Issued at 325 PM CDT Sat Oct 14 2017

The upper trough that is forecast to move through
Sunday night will probably produce lake effect clouds across
northern Wisconsin with clearing across central Wisconsin. Frost
possible across central Wisconsin if skies are clear. Lows will be
in the low to mid 30s.

Pretty quiet weather is expected monday through Saturday with
mostly zonal flow and just a few weak shortwaves moving through
with little moisture. So dry and mild is what we are forecasting.

.AVIATION...for 06Z TAF Issuance
Issued at 1026 PM CDT Sat Oct 14 2017

Flight conditions were IFR/LIFR across most of the forecast area
late this evening. One area of showers and embedded thunderstorms
was headed for the Fox Valley and Lakeshore areas, and is expected
to exit eastern WI early in the TAF period. Another area of rain
associated with an upper level trough covered most of Minnesota
and northwest WI, and is expected to move through the forecast
area late tonight into Sunday morning. The rain will taper off
during the mid to late morning as the trough departs. Strong gusty
northwest winds will develop as low pressure departs and a cold
front moves through late tonight into Sunday morning, with gusts
to 30 to 35 knots expected. Flight conditions should steadily
improve during the morning, and return to VFR in most locations
by late morning or early afternoon. Clearing skies and decreasing
winds are expected in the late afternoon and evening.

Issued at 325 PM CDT Sat Oct 14 2017

An intensifying area of low pressure will move through the region
tonight into Sunday morning.

East winds reaching small craft criteria may briefly diminish
this evening as the low moves across Wisconsin. As the surface
low departs later tonight, winds are forecast to rapidly shift to
the northwest and become gusty into Sunday. A period of gale force
gusts are expected from late tonight through Sunday afternoon when
a Gale Warning is in effect for the entire area.

Wind Advisory from 7 AM to 4 PM CDT Sunday for WIZ022.


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