Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 200332

Area Forecast Discussion
National Weather Service Green Bay WI
1032 PM CDT WED OCT 19 2016

Updated aviation portion for 06Z TAF issuance

.SHORT TERM...Tonight and Thursday
Issued at 213 PM CDT Wed Oct 19 2016

The latest RAP analysis and satellite/radar imagery show a cold
front moving southeast from Red Wing to Rhinelander early this
afternoon.  Temps are in the 60s ahead of the front, and fall back
into the 50s behind it.  Some cu has developed along and behind the
boundary, but the widespread overcast conditions reside north of the
U.P. border and farther west into Minnesota.  The rest of area is
seeing scattered mid and high clouds overhead, with a more
widespread batch over South Dakota that is struggling to move into
Wisconsin.  With no precip expected along or behind the front, sky
and temp trends are the main forecast concerns.

Tonight...The cold front will be exiting eastern WI during the
evening.  Little in the way of clouds associated with the front, but
scattered to broken mid and high clouds will continue to pass
overhead before departing overnight.  Scattered lake clouds may also
move into far northern WI as 850mb temps fall to -5C over western
Lake Superior. Colder lows with a slight north wind into the low 30s
north to low 40s south.

Thursday...A large scale trough will be moving into the western
Great Lakes above a chilly airmass with brisk northwest winds.  With
daytime heating and flow continuing off Lake Superior, should see
plenty of cloud cover develop over northern Wisconsin.  Downsloping
should help keep eastern WI partly sunny.  As a result, temps will
be cooler over the north, only into the low to mid 40s.  Highs over
eastern WI should reach into the lower 50s.

.LONG TERM...Thursday Night Through Wednesday
Issued at 213 PM CDT Wed Oct 19 2016

Ridging will become established across the western Great Lakes
region by late this week, bringing a long period of dry weather
that is expected to last through the weekend and into early next
week. The main concern during this period will be temperatures, as
a cold airmass brings overnight lows into the upper 20s to middle
30s Thursday night and Friday night, with daytime highs on Friday
limited to the middle 40s to around 50 degrees. Once this cold
period is overcome, temperatures will slowly rebound during the
weekend and into early next week, with highs on Sunday reaching
the middle to upper 50s.

After the relatively dry, quiet period has passed a powerful low
pressure system will affect the western Great Lakes Tuesday and
next Wednesday. This system will bring the possibility of heavy
rain and some thunderstorms as modest instability advects north
Tuesday night and next Wednesday. There are still significant
model differences regarding the strength, timing and path of this
system so details are uncertain. However it appears more likely
that there will be a period of unsettled weather during this
portion of the extended.

.AVIATION...for 06Z TAF Issuance
Issued at 1030 PM CDT Wed Oct 19 2016

The main aviation forecast issue continues to be what will happen
to expansive low cloud deck across much of MN and Lake Superior.
It has begun sagging south this evening, and expect that trend to
continue. Weak downslope component into east-central WI will
probably delay low clouds in that area until some convective
cloudiness forms mid-morning tomorrow.



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