Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 171109

Area Forecast Discussion
National Weather Service Green Bay WI
509 AM CST Fri Nov 17 2017

Updated aviation portion for 12Z TAF issuance

.SHORT TERM...Today...Tonight...and Saturday
Issued at 300 AM CST Fri Nov 17 2017

After some light snow showers and flurries early this morning,
additional precipitation will arrive from the west as a low
pressure system tracks through the western Great Lakes region.
Model soundings indicate moisture will be at a premium this
morning, with a layer of warm air around 800 to 850 mb. This will
open the door to all kinds of precipitation types, from snow,
freezing drizzle, sleet and plain drizzle. Surface and road
temperatures indicate the best possibility for icy roads will be
north of a line from Marshfield, to Shawano, to Wausaukee. This
could negatively impact the morning commute across these areas.
The threat for icy roads will diminish from south to north as road
temperatures warm above freezing this morning. Given the narrow
window of icy precipitation no headlines are anticipated this

By this afternoon deeper moisture is expected to arrive, which
will transition the drizzle to more of a light rain across the
region. Afternoon highs are expected to range from the middle 30s
across north-central Wisconsin, to around 40 across east-central
and the lakeshore counties.

Rain will diminish from west to east tonight as the low tracks
away from the region. Model soundings once again show moisture
stripped out of the column and a transition from rain to more of a
drizzle precipitation type. As temperatures once again fall
freezing drizzle will once again be on the table across north-
central and portions of central Wisconsin late tonight. Lows
tonight are expected to range from the upper 20s across the north,
with lows in the lower to middle 30s across the south.

A mid level PV anomaly will track through on Saturday, bringing
another chance for precipitation to the area as a surface low
tracks to the south. Across the north, lake effect snow showers
will form across far north-central Wisconsin as the Lake Superior
snowbelt becomes activated. Model soundings continue to indicate
a lack of deep moisture, making for a wintry mix across most of
the area during the morning hours. Highs on Saturday will
generally be in the 30s.

.LONG TERM...Saturday Night Through Thursday
Issued at 300 AM CST Fri Nov 17 2017

Fairly tranquil pattern expected across the region through the
period. There are small chances for lake effect snow showers
across far northern Wisconsin Saturday night into Sunday morning,
and then again Tuesday into Tuesday night.

Gusty northwest winds will gradually diminish Saturday night.
It will be seasonably cold with lows in the teens to middle 20s.
Any lake effect snow showers should be light in intensity across
Vilas county, however could still produce some slick spots on
area roads. On Sunday, skies will be partly cloudy with high
temperatures running about five degrees below normal. Much warmer
conditions return on Monday ahead of the next cold front. Highs
most places will be in the 40s. The front will come through dry
Monday night with high temperatures on Tuesday about 5 to 10
degrees cooler than Monday. Seasonable temperatures are expected
for the remainder of the work week.

.AVIATION...for 12Z TAF Issuance
Issued at 509 AM CST Fri Nov 17 2017

Solid MVFR and IFR conditions have settled in across the TAF sites
early this morning. A band of mixed precipitation will mainly
affect the north this morning, before deeper moisture causes
mainly rain during the afternoon as temperatures rise above
freezing. Mixed precipitation is possible again late tonight
across the north as surface temperatures cool and mid level dry
air causes the loss of ice crystals. Further south rain will
transition to drizzle with the loss of deeper moisture overnight.
Conditions are expected to bounce between MVFR and IFR for most of
the TAF period.

Issued at 300 AM CST Fri Nov 17 2017

A low pressure system tracking through the Great Lakes will bring
additional chances for gale force winds, first from the south today
ahead of the system, then from the northwest behind the system on
Saturday and Saturday evening. A Gale Warning continues for the
Lake Michigan nearshore waters today, however confidence is not
high enough to issue any headlines for Saturday as recent model
runs have lowered wind gusts across the nearshore waters.



SHORT TERM.....Kurimski
LONG TERM......Eckberg
MARINE.........Kurimski is the U.S. government's official web portal to all federal, state and local government web resources and services.