Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 150357
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
957 PM CST Tue Nov 14 2017

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Wednesday
Issued at 235 PM CST Tue Nov 14 2017

An approaching surface system and mid level trough will combine
with increasing low level moisture to bring rain to the area
during the night. A coupled upper jet structure is expected to
enhance rainfall across parts of northeast Wisconsin late tonight
into early Wednesday morning.

Temperatures were in the mid 30s to lower 40s at 20Z and there was
some fog and drizzle, mainly in north central and parts of
central Wisconsin. The surface pressure gradient is tight enough
to keep winds from dropping off during the night and there will be
plenty of clouds over the forecast area. Expect the wind, clouds
and warm advection to result in nearly steady or slowly rising
temperatures most of the night, though it will cool off a bit
late this afternoon into early this evening.

Colder air moving in behind the departing surface system will
result in falling temperatures starting around midday on
Wednesday. Rain should gradually come to an end during the day,
but snow showers are expected across north central Wisconsin due
to cold advection over the warmer waters of Lake Superior. Any
accumulation before 00Z Thursday should be minor.

.LONG TERM...Wednesday Night Through Tuesday
Issued at 235 PM CST Tue Nov 14 2017

The main forecast concern is the potential for minor LES snow
accumulations over Vilas county Wednesday night, and impacts from
a potentially strong storm Friday into Saturday night.

Conditions still look favorable for a brief period of lake-
enhanced snowfall over far north central WI (especially Vilas
county) on Wednesday night. Low-level wind trajectories will veer
NNW as Lake-850 mb delta-T`s increase to 15-17 C, and the passage
of a sharp upper trof will provide a few hours of synoptic
enhancement in the evening. Will continue to carry likely pops in
northwest Vilas county, along with snowfall totals of 1-2 inches.

High pressure will bring a brief period of dry weather on
Thursday and Thursday evening.

Models have continued their trend toward a somewhat weaker low
pressure system affecting the region for the end of the work week
and beginning of the weekend. Most of the individual GFS ensemble
members are also weaker than the previous model run. Any phasing
or rapid deepening of the low appears likely to occur well east
of WI, resulting in less chance of accumulating snow or Gale force
winds. Despite this, there could be some minor travel impacts due
to mixed precipitation over north central and parts of central
and northeast WI Friday morning. Precipitation should change to
all rain Friday afternoon, then transition back to mixed rain/snow
or snow from northwest to southeast Friday night into Saturday
morning. Lake effect snow showers are expected in north central WI
Saturday afternoon and night, followed by fairly quiet weather for
the beginning of next week.

Temperatures will be below normal through most of the period,
with the coldest readings occurring Saturday night through Sunday
night.
&&

.AVIATION...for 06Z TAF Issuance
Issued at 957 PM CST Tue Nov 14 2017

Look for widespread IFR and LIFR conditions overnight as a
frontal system tracks across the region. Light rain and drizzle
will become more widespread overnight. Areas of fog over central
and north central Wisconsin will spread eastward overnight and
linger into Wednesday morning. Conditions to gradually improve
after the cold front passage Wednesday morning. West winds in the
wake of the cold front will turn blustery in the afternoon while
cigs and vsbys continue to improve to a MVFR level or lower end
VFR levels over most areas. Scattered snow showers will be on the
increase over north central Wisconsin Wednesday evening as colder
air on northwest winds pour over Lake Superior.
&&

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

$$

SHORT TERM.....MG
LONG TERM......Kieckbusch
AVIATION.......TDH



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