Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 262029
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
229 PM CST Sat Nov 26 2016

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Sunday
Issued at 228 PM CST Sat Nov 26 2016

Partly sunny skies prevailed across the region this afternoon.
Temperatures were in the middle to upper 30s north, and in the
40s over the remainder of the forecast area.

Main concern for tonight will be low temperatures and fog. With
clear to partly cloudy skies, light winds and relatively high
dewpoints this afternoon, expect areas of fog to form late this
evening and continue into Sunday morning. The fog will be locally
dense with visibilities of a quarter of a mile or less, especially
across north-central Wisconsin where a snowpack lingers. Also of
concern, the combination of the fog and road temperatures expected
to fall below freezing tonight may result in areas of black ice to
develop on area roads, bridges and sidewalks.

The fog will linger into Sunday morning across much of the area.
There is some concern the fog could linger into the afternoon
across far north-central Wisconsin where upslope flow would occur
and where there is a snow pack. It will be mild on Sunday with
highs mainly in the 40s, although it may remain in the upper 30s
where fog lingers into the afternoon.

.LONG TERM...Sunday Night Through Saturday
Issued at 228 PM CST Sat Nov 26 2016

Precipitation trends and type in association with an upper level
low will be the main forecast concerns through the extended
period.

Stacked surface/upper lows will track from the Northern Plains
on Sunday to northwest WI by Tuesday or Tuesday night. A
significant band of rain will develop in advance of this system,
and lift northeast through the forecast area Sunday night. This
band will form in association with strong WAA/Isent Lift with a
40-50 kt low-level jet. Weak dry slotting should cause the steady
rain to become showery or to change to drizzle at times on Monday.
A second significant band of rain will develop as an occluded
front and the RRQ of an upper jet moves through on Monday night.
Lingering showers can be expected over northern WI on Tuesday.
1000-850 mb thicknesses and low-level wet bulb temperatures
support all rain through Tuesday, with the exception of a possible
mix of rain/snow over far north central WI late Tuesday afternoon.

The upper low is expected to wobble around the Minnesota/Western
Great Lakes region through the latter half of the work week, with
scattered rain or snow showers continuing, especially west and
north of the Fox Valley and Lakeshore areas. Overall,
precipitation amounts should be light during this period.

Temperatures will start off well above normal, then trend closer
to normal, at least for high temperatures, later in the week.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1144 AM CST Sat Nov 26 2016

Some patchy MVFR cigs continued across portions of north-central
and northeast Wisconsin late this morning, and should continue
into the afternoon before the entire area becomes VFR. The VFR
conditions will not last long, as low clouds and fog are expected
to develop across much of the area later this evening and
especially into the overnight hours and early Sunday morning.
IFR conditions or lower are expected across north-central
Wisconsin where lights winds and snow cover will aid in the
formation of fog. The fog will gradually burn off on Sunday
morning. It will probably take longest across north-central
Wisconsin due to upslope flow and snow cover and the low sun
angle. It is possible the fog may not clear until afternoon.
&&

.MARINE...
Issued at 228 PM CST Sat Nov 26 2016

Gale force gusts are possible late Sunday night into Monday
night. The pressure gradient will tighten as a strong low
pressure system approaches the Upper Mississippi Valley Sunday
night. 925/850 mb winds are forecast to increase to 35-45 kts,
and mixing should allow higher momentum to mix to the surface,
especially on our Lake Michigan zones. Changed the start time to
midnight Sunday night, as gusts to gale force look like they will
commence a little earlier than previously thought, at least over
our southern marine zones.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....Eckberg
LONG TERM......Kieckbusch
AVIATION.......Eckberg
MARINE.........Kieckbusch



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