Area Forecast Discussion
Issued by NWS Green Bay, WI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KGRB 060439

Area Forecast Discussion
National Weather Service Green Bay WI
1039 PM CST Mon Dec 5 2016

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Tuesday
Issued at 231 PM CST Mon Dec 5 2016

Short term forecast will feature a couple chances for spotty
precipitation, however in general low impact weather is expected.

Precip chance 1...drizzle/freezing drizzle this evening and early

Strong WAA continues to push into northeast Wisconsin this
afternoon, with low clouds and some fog developing in the vicinity
of the warmest air aloft. Cloudy skies and patchy fog will
continue to nudge northward through the afternoon as the strongest
WAA moves into the area. The question will be if any drizzle can
be squeezed out of these clouds. Right now, moisture is lacking
and any pcpn has yet to be reported. However, some of the hi-res
short term models do show low level moisture pooling in northern
Wisconsin late this evening. If enough moisture can develop, drizzle
is possible late this evening through around midnight. Freezing
drizzle may become an issue if we do eventually get anything to
develop as it would be after sunset. Not much QPF is expected so
no major impacts are expected if freezing drizzle does occur,
though a few spots may become slick. Drizzle should come to an end
after midnight as the surge of WAA shifts outside of the area.

Precip chance 2...cold front Tuesday

A cold front will sweep through NE WI Tuesday and bring a chance
of precipitation to the area. Models show some disagreement on
how widespread the precip will be. Based on the moisture profiles-
favored a slower, less widespread solution. With moisture limited
to the vicinity of the cold front, think precip chance will be
tied to the frontal passage and not much showery activity will
develop far ahead of it. Strong low to mid level forcing with the
front combined with upper level divergence does mean showers are
likely to develop where there is enough moisture. As we deepen the
forcing and cloud mechanisms, snow will become the predominant
type through Tuesday morning as the front pushes through northern
and central Wisconsin. As the front and associated precip move
into eastern portions of the state, low level temperatures should
be warm enough for a rain/snow mix or just rain. Otherwise, a
cloudy day is expected.

The bigger impact from the cold frontal passage will be
temperatures. Behind the front, arctic air will filter into the
state. In north central Wisconsin, Tuesday will be the kind of
day where highs will be in the morning, and temperatures will
then fall through the day. Eastern Wisconsin should see some
warming before the cold front swings through early Tuesday
afternoon. Near to below normal temperatures are then expected
through the near future at least.

.LONG TERM...Tuesday Night Through Monday
Issued at 231 PM CST Mon Dec 5 2016

Temperatures will be turning colder during the forecast period,
but will only be 3 to 5 degrees below normal. There will be a
steady wind with wind chills in the single numbers and teens much
of the time.

Not much snow expected with northwest flow surface and aloft,
except in far northcentral Wisconsin where parts of Vilas county
could get several inches of lake effect snow Wednesday night
through Thursday night. Parts of the forecast area could see a
light snowfall Saturday night and Sunday, but there is a lot of
disagreement among the models.

The long range weather pattern favors a trend towards colder
weather by mid December, but the really cold air looks to stay in
Canada for the time being.

.AVIATION...for 06Z TAF Issuance
Issued at 1034 PM CST Mon Dec 5 2016

Expect IFR/LIFR ceilings and some MVFR/IFR fog the rest of
tonight and early Tuesday morning. A cold front will arrive in
north central and central WI Tuesday morning, and eastern WI in
the afternoon. Moisture may deepen enough for a brief period of
light freezing rain or freezing drizzle in north central and
central WI very late tonight into early Tuesday. The front will
bring a period of snow showers to north central and parts of
northeast and central WI, and mainly flurries or drizzle
elsewhere. North central WI could pick up an inch or so of
accumulation. Gusty west-southwest winds will develop in the wake
of the front late in the day. A gradual improvement in ceiling
heights is anticipated during the afternoon and early evening.

LLWS is possible at the RHI/AUW/CWA TAF sites through the
overnight hours, as south winds increase to 35 to 40 kts off the



SHORT TERM.....Allen
AVIATION.......Kieckbusch is the U.S. government's official web portal to all federal, state and local government web resources and services.