Area Forecast Discussion
Issued by NWS Green Bay, WI

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986
FXUS63 KGRB 260447
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1047 PM CST Sat Feb 25 2017

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Sunday
Issued at 224 PM CST Sat Feb 25 2017

The latest RAP analysis and satellite/radar imagery show a large low
pressure system continuing to exit the region over northwest Quebec.
Cloud cover, snow showers, and flurries wrapping around the low are
persisting early this afternoon over north-central and eastern
Wisconsin.  The back edge of the clouds are pushing into western
Marathon and Wood counties, and should exit northeast Wisconsin by
late this afternoon or early this evening.  Looking to the west, a
corridor of clearing has moved into western Wisconsin and eastern
Minnesota in close proximity to a surface ridge axis.  The next
system, however, is already diving southeast across the northern
Plains with scattered snow showers over North Dakota and northern
Minnesota.  Forecast concerns revolve around cloud trends this
afternoon, followed by snow shower chances late tonight into Sunday
with this next system.

Tonight...A weak surface ridge axis will pass across the area and
provide a brief period of clearing during the first half of the
evening.  Then will see increasing clouds again from the west as
warm advection pushes in aloft ahead of a weak shortwave. Saturation
looks deep enough over north-central and central WI for a chance of
snow showers overnight, but not expecting much in the way of
accumulations.  With cloud cover and a tight pressure gradient, low
temps should not fall much, and will go with lows in the teens.

Sunday...That shortwave will slide across the area while pushing a
cold front into central and north-central WI.  The front looks
relatively sharp with decent convergence that will provide a focus
for snow shower development with heating of the day.  Would not be
surprised if a few snow showers become briefly heavy given mid-level
lapse rates around 7 c/km.  Up to an inch of snow looks possible
over Vilas county. Chances of snow showers are less over eastern
Wisconsin but dont think can rule them out with passage of the
shortwave and aforementioned lapse rates.  High temperatures will
rise to near 30 degrees in the north, to the middle 30s south and
east.

.LONG TERM...Sunday Night Through Saturday
Issued at 224 PM CST Sat Feb 25 2017

A weak ridge near the surface will help keep the area dry Sunday
night and into Monday night, ahead of an approaching surface low
with associated upper level trough.

As precipitation enters the region, a brief period of wintry mix
is expected to move across areas of northern Wisconsin while rain
remains the primary weather type towards the Fox Valley. As warm
air advection takes over near the surface in the mid to late
morning, rain will overspread the remaining areas in the north. A
slow switch back to snow is anticipated in the evening. This
transition will spread north to south as weak cold air advection
filters in behind this system. A brief break in the action is
expected as some dry air works its way in the back end of this
system in the early morning Wednesday before another shortwave
comes through to fill in some additional snow shower chances for
Wednesday morning to afternoon. A brief clipper system is still
expected to follow Thursday as northwesterly flow dominates,
bringing additional snow chances mainly to the northern areas.
Weak lake effect snow signals then linger on into next weekend.

A warming trend is expected ahead of the trough through Tuesday as
temperatures rise to well above normal, followed by a slow
cooling trend back to near normal by Thursday. Northwesterly flow
into the weekend will then bring temperatures to a few degrees
below normal by Saturday.
&&

.AVIATION...for 06Z TAF Issuance
Issued at 1047 PM CST Sat Feb 25 2017

Clouds continue to track from west to east tonight, bringing a
shield of clouds back to the TAF sites. Clouds will gradually
lower overnight into the low MVFR range over central and north-
central Wisconsin, with potential for light snow
showers/flurries. Scattered snow showers will likely persist
across northern Wisconsin for much of Sunday with arrival of a
cold front, and possibly push into the Fox Valley/Lakeshore areas
during the morning. IFR visibilities will be possible within any
snow showers. Conditions should then improve back to VFR by Sunday
afternoon and evening as the front tracks east.
&&

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

$$

SHORT TERM.....MPC
LONG TERM......Uhlmann
AVIATION.......Kurimski



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