Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 151815

Area Forecast Discussion
National Weather Service Green Bay WI
1215 PM CST Wed Feb 15 2017

Updated aviation portion for 18Z TAF issuance

Issued at 245 AM CST Wed Feb 15 2017

Quiet mid-winter weather expected. Seasonable temperatures today
and tomorrow, then a prolonged stretch of much above normal

The upper flow across central and eastern North America will
remain split during the period as a positive upper height anomaly
shifts from the intermountain West to around 80W. The forecast
area will remain primarily under the influence of the northern
branch of the split. This will result in little precipitation
until at least early next week. The upper flow feeding into the
forecast area is currently northwesterly. This will result in near
normal temperatures the next couple days as the southwest flank
of a cold Canadian air mass brushes across the area. Once that
air mass shifts off to the east, readings will warm to
significantly above normal levels for the rest of the period.

.SHORT TERM...Today...Tonight...and Thursday
Issued at 245 AM CST Wed Feb 15 2017

Subsidence and dry air have kept lake-effect in check thus far.
Trajectories will remain favorable for snow showers and flurries
in the snowbelt today, but accumulations will be minor. Otherwise,
it appears clouds will overspread the rest of the area today. Then
expect variable sky conditions late today through Thursday as
patches of clouds at various levels stream across the region.

Guidance has generally been on the low side for temperatures
recently. Expect that trend to continue for today and Thursday
despite the arrival of a cooler air mass. Temperatures tonight
are more problematic. Surface ridge will be edging into the area,
resulting in diminishing winds. There is enough lingering snow
cover, especially across the north, to allow temps to drop sharply
during any periods with clear skies. But considering the
uncertainty/expected variability in sky condition, the best course
of action seemed to be to stick close to a broad-based blend of
guidance products for tonight`s low temperatures.

.LONG TERM...Thursday Night Through Tuesday
Issued at 245 AM CST Wed Feb 15 2017

Split flow will be the predominate pattern across North America for
much this period, with above normal mid-level heights over the
western Great Lakes.  Though much of the period is expected to be
dry, will see increasing chances of rain early next week when low
amplitude shortwaves slide east out of the mean west coast trough.
The gfs and ecmwf are having trouble resolving the details of these
shortwaves, but will put more weight into the ecmwf.

Thursday night through Sunday night...Warmer air will begin to
invade the region on Thursday night into Friday.  Some mid and high
clouds will accompany the warm advection, but the atmosphere looks
too dry for any precip chances.  Will see increasing sunshine on
Friday as the warm advection clouds pull out.  Widespread 40s are
expected for highs on Friday, though a light southeast wind will
keep the lakeshore areas in the upper 30s.  Winds will turn more
offshore on Friday night into Saturday which should lead to the
warming trend continuing.  Still see signs of a weak trough crossing
the area on Saturday, but there is no moisture above 850mb.  Quiet
and mild weather will continue on Saturday night and Sunday, before
clouds increase ahead of the next system on Sunday night.

Rest of the forecast...Rain chances will increase on Monday and
Monday night as a shortwave and associated cold front pass across
the region. Temps will remain too warm for any threat of snow with
the system. Upper flow will remain out of the southwest behind the
system, so think will see another precip chance arrive by midweek.
Temps will likely start to cool off behind this mid week system.

.AVIATION...for 18Z TAF Issuance
Issued at 1215 PM CST Wed Feb 15 2017

MVFR or low end VFR cloud bases are expected to continue this
afternoon across northern and eastern WI as lake effect clouds
slowly erode as wind trajectories become less favorable. Snow
showers and flurries are also expected through the afternoon,
mainly across northern WI and Door County. Mid and upper level
clouds are expected across central WI through the afternoon as
well. Cloud bases across the area tonight are expected to mainly
be VFR; however, some lower bases are possible across central and
north central WI overnight into Thursday.



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