Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 161005

Area Forecast Discussion
National Weather Service Green Bay WI
405 AM CST Tue Jan 16 2018

Forecast discussion for routine morning forecast issuance

.SHORT TERM...Today...Tonight...and Wednesday
Issued at 404 AM CST Tue Jan 16 2018

lake effect snow will exit Kewaunee and Manitowoc counties around
daybreak as winds back towards the north. In addition, lake effect
snow in Vilas county will diminish by midday. Highs today will be
pretty close to normal.

Strong pressure gradient sets up late tonight which should keep
temperatures from falling much below normal despite fresh snow.

Pressure gradient tightens even more Wednesday, and models forecast
925 mb winds to increase to 40 to 50 knots across northeast
Wisconsin by midday. Low level temperature inversion will keep
winds that strong from mixing down to the surface, but think that
wind gusts to 30 mph or more are possible across the bay and the
Door peninsula, where a foot or more of fresh snow has fallen.
This could produce whiteout conditions over the frozen bay and
parts of the lake shore counties. Drifting snow driven by southwest
winds could make travel on north south roads difficult.

.LONG TERM...Wednesday Night Through Monday
Issued at 404 AM CST Tue Jan 16 2018

The latest ensemble means indicate that the upper air pattern
will undergo a transition later this week, as the large western
North American ridge flattens, while a potent Pacific trough moves
into the desert SW. This Pacific trough could have significant
impacts on our weather late this weekend. In the meantime, the
ecmwf and gfs are in relatively good agreement, so a general blend
will suffice.

Wednesday night through Thursday night...High pressure will be
centered over the Gulf coast while the next clipper will be quickly
diving southeast over far south-central Canada on Wednesday night.
The airmass will be quite dry ahead of the clipper, and will likely
only see an influx of high clouds.  However, the pressure gradient
will remain relatively tight, so blowing and drifting snow will
remain a concern, especially over eastern WI.  The clipper will move
across the Lake Superior region on Thursday.  The deepest
moisture/forcing will remain north of the state, but will have just
enough for chance of snow over far northern WI.  Not expecting much
accums though.  Temps will continue to moderate, and winds will
remain breezy.  The clipper exits by Thursday night, and should see
the clouds depart.  Winds will slacken somewhat, but should not
decouple, so temps should remain mild.

Rest of the forecast...Warmer air will continue to invade the region
for Friday into Saturday.  Temps will likely be well above normal
for these days, with only periods of scattered to broken mid and
high clouds overhead.  Colder air will be pushing southward out of
Canada on Sunday as high pressure builds into the northern Plains.
Meanwhile, low pressure will be gathering strength over the southern
Plains.  There will not be much cold air over the region by this
time, so track of the cyclone will be critical for the impacts on
our weather.  Regardless, there is enough agreement between the
ensemble means and the operational models to suggest a large system
will impact the region in the Sunday to Monday time period.

.AVIATION...for 06Z TAF Issuance
Issued at 846 PM CST Mon Jan 15 2018

Ceilings will remain mixed VFR and MVFR as scattered snow showers
and flurries affect much of the area. The exception will be the
east, where lake-effect snow showers will continue into early
Tuesday, resulting in IFR and even LIFR conditions at times.

Winter Storm Warning until 6 AM CST early this morning for


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