Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 182138

Area Forecast Discussion
National Weather Service Green Bay WI
338 PM CST Wed Jan 18 2017

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Thursday
Issued at 337 PM CST Wed Jan 18 2017

Clouds trends, fog potential and temperatures are the main
forecast concerns.

West-southwest winds and daytime heating have eroded the low
clouds across the region, with only a few small patches of
stratus lingering in our far eastern counties this afternoon.
With a strengthening low-level inversion expected tonight and
some low-level moisture from melting snow/ice in place, low
clouds may redevelop late tonight. The most likely area of
development will be the higher terrain of north central WI,
where models suggest the greatest 950-925 mb RH will reside,
and some weak upslope will occur. Patches/areas of fog are
also possible, especially over north central and far northeast
WI, where boundary layer winds will decrease to 15-20 kts
overnight. Used a blend of the better performing guidance sets
for Min temps tonight, with readings expected to range from the
lower 20s far northeast to the middle to upper 20s elsewhere.

On Thursday, expect a gradual erosion of the low stratus over
north central WI, with fog mixing out by late morning. Although
high/mid clouds will gradually increase during the day, there
should be enough sunshine to boost high temperatures into the
upper 30s and lower 40s in most areas. The warmest readings are
expected in the higher elevations of north central WI (where
mixing will tap into the warm layer aloft), and the typical
warm spots in central WI.

.LONG TERM...Thursday Night Through Wednesday
Issued at 337 PM CST Wed Jan 18 2017

A closed 500mb low will become an open wave as it approaches the
Great Lakes Region from the Plains. It will bring precipitation
chances to the forecast area starting on Thursday night, but type
is a concern since warm advection aloft will likely result in
liquid falling into the surface cold layer. Low level temperatures
will determine who gets rain and who gets freezing rain. A little
sleet is also in the forecast but think that rain or freezing
rain will be the primary precipitation types until low levels warm
up by Friday afternoon and bring any freezing rain to an end.

PoPs decrease as the system departs but another mid level trough
will move into Wisconsin and bring precipitation, mainly rain,
chances into the area starting on Friday night. The blended model
solution keeps at least slight chance PoPs for every period
throughout the rest of the forecast. A more significant system
will develop over the western CONUS and begin to impact the area
around the middle of next week. There were still timing
differences among the models so confidence in the exact timing is

Expect daytime highs to remain well above normal through the end
of the forecast period.

.AVIATION...for 18Z TAF Issuance
Issued at 1127 AM CST Wed Jan 18 2017

Low stratus will continue to erode across eastern WI early this
afternoon, leaving mostly clear skies across the region. Some
borderline LLWS is expected to develop later this afternoon and
continue into the evening, as west winds increase to about 35 kts
just above a low-level inversion. Low stratus and possibly some
fog is expected to redevelop overnight, mainly over north central



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