Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 241946

Area Forecast Discussion
National Weather Service Green Bay WI
246 PM CDT Sat Jun 24 2017

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Sunday
Issued at 246 PM CDT Sat Jun 24 2017

Expect the majority of the showers and scattered thunderstorms,
that were across northeast Wisconsin this afternoon, to diminish
as a cold front passes and the sun sets. Think there will still
be at least scattered showers around this evening before activity
increases again with a 500 mb low moving into, and then across,
Wisconsin overnight. Models showed a 500 mb ridge moving though
the area Sunday morning before the next 500 mb trough moves in
later in the day so activity should increase later in the day.
Cold air aloft and a surface trough/front will also contribute to
the chance for showers and storms. Low wet bulb zero heights will
bring a chance for small hail with thunderstorms and gusty winds
are also possible.

Cooler than normal conditions will prevail tonight and highs on
Sunday will be at least 10 degrees below normal at most locations.

.LONG TERM...Sunday Night Through Saturday
Issued at 246 PM CDT Sat Jun 24 2017

Upper mean flow over CONUS still expected to transition from the
large mean trough over eastern half of the U.S. with ridge over
over the far west to a more zonal pattern.

Cool air aloft may produce enough instability for a few showers
Monday afternoon, but overall, the work week will start out drier
than this weekend.

Gulf moisture returns and moderate warm air advection sets stage
for thunderstorms Wednesday of shortwave trof in zonal flow.
Occlusion/cold front moves through late Wednesday, but question as
to how far south front moves before stalling and possible surface
wave development. There`s actually some general agreement between
GFS and ECMWF on this scenario, but details to be determined. In
any event, active weather expected in the western Great Lakes
region for the Wednesday-Friday period.

After a cool start to the week, temps will be a couple degrees
either side of normal for much of the period.

.AVIATION...for 18Z TAF Issuance
Issued at 1242 PM CDT Sat Jun 24 2017

Ceilings at 17Z were MVFR across much of the area north of
Highway 29 and VFR over the rest of the area. Showers, with
isolated thunder, developed across the northeast part of
Wisconsin. Expect more showers and storms to develop later in the
afternoon. A 500mb low is forecast to move into Wisconsin during
the evening and pass through the state overnight, so would not
expect showers/storms to completely end with loss of daytime
heating. There may be some MVFR/IFR fog across the northern part
of the state overnight.



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