Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 282334

Area Forecast Discussion
National Weather Service Green Bay WI
634 PM CDT WED SEP 28 2016

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Thursday
Issued at 249 PM CDT Wed Sep 28 2016

Surface and upper level cyclones centered over northern Indiana
this afternoon were forecast to move to Kentucky by 00Z Friday.
There were scattered showers across eastern and central Wisconsin
today but low level dry air resulted in some clearing from about
the Fox Valley east to Lake Michigan as of 19Z. Low level lapse
rates were quite steep over most of the area during the afternoon,
so showers should die off with the loss of daytime heating. Water
vapor IR imagery showed some drier air across the northwest half
of Wisconsin as it gets wrapped around the upper cyclone.

Showers should end late this afternoon, but clouds will hang
around a while longer across much of the forecast area. Have
mentioned patchy fog late tonight since models suggest that there
will be some fog development in northern and central Wisconsin.
Kept it out of the east due to stronger surface flow. Expect
sunshine and warmer than normal temperatures on Thursday.

.LONG TERM...Thursday Night Through Wednesday
Issued at 249 PM CDT Wed Sep 28 2016

Progs continue to focus on the upper low, which dominated the
weather regime early this week, to lift back northward friday and
linger over the area for much of the weekend. As a result, plenty
of clouds along with a chance of showers will persist into at
least Saturday before tapering off from west to east Saturday
night into Sunday. Various relative humidity panels and cyclonic
flow support clouds lingering into Sunday. Drier air wrapping
around the low may hold off pcpn and clouds a bit over far
northern and western areas at times this weekend.

An upper ridge drifts over late Sunday into the start of the new
work week in the upper lows departure, for a drier period. Some
progs do develop some spotty light pcpn in the return warm air
return flow ahead of an approaching trough over the plains. Progs
then divert next week with the next chance of rainfall due to
differences with a nearly stalled upper pattern for next week
which includes location and tracking of a tropical system across
or near the east coast next week.

.AVIATION...for 00Z TAF Issuance
Issued at 623 PM CDT Wed Sep 28 2016

Surface/upper lows have dropped into the Ohio Valley, causing
showers to end and skies to clear over most of the forecast area.
Northeast flow off Lake Superior will probably result in a feed
of scattered to broken low clouds into north central WI tonight.
MOS guidance and models suggest that some fog may develop in north
central WI overnight, but with some lingering wind at the surface
and 15 to 20 kt boundary layer winds, suspect this may end being
more of a stratus deck. Have put a tempo group in the RHI TAF for
a period of low stratus late tonight into early Thursday morning.
Expect VFR conditions at the other TAF sites, with gusty northeast
winds perking up again by late morning, especially in the Fox
Valley region.




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