Area Forecast Discussion
Issued by NWS Green Bay, WI

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FXUS63 KGRB 251741

Area Forecast Discussion
National Weather Service Green Bay WI
1241 PM CDT TUE OCT 25 2016

Updated aviation portion for 18Z TAF issuance

.SHORT TERM...Today...Tonight...and Wednesday
Issued at 337 AM CDT Tue Oct 25 2016

After a cold mostly sunny morning, clouds will increase today
ahead of an approaching trough developing across the central
Plains. Rain from this system is not expected to arrive until
tonight when better moisture and mid level frontogenesis arrive
from the southwest. Pops will gradually increase tonight from
southwest to northeast as this system approaches. While surface
temperatures in the lower 30s across the far north seem cold
enough for snow tonight, the abundant cloud cover should mean
evening lows with increasing temperatures later at night.

The surface low will pass to the south on Wednesday, with abundant
moisture and isentropic lift. Rainfall amounts later tonight and
into Wednesday could approach or exceed an inch, especially across
the southern cwa closer to the better moisture and lift. Despite
the high QPF amounts, the time range the rain is expected should
help minimize flooding concerns. Highs on Wednesday will be well
below normal, with temperatures in the lower to middle 40s.

.LONG TERM...Wednesday Night Through Monday
Issued at 337 AM CDT Tue Oct 25 2016

The latest gfs ensemble mean indicates that the upper flow will
consist of upper troughs off the west and east coast of the conus,
and above normal heights over the middle of the country for much of
this period.  Low amplitude shortwave impulses will periodically
eject out of the west coast trough and provide the region with
precip chances.  One of these impulses will be exiting the region on
Wednesday night.  Another system is progged to cross the region late
Friday into early Saturday, but models show plenty of spread with
the timing and strength of this system.  Will take a blend of the
gfs/ecmwf to mitigate some of the differences.

Wednesday night through Thursday night...Low pressure will be moving
across the southern Great Lakes on Wednesday night. Light
precipitation is expected to continue over much of the area during
the evening within the comma head of the system, then exiting
overnight over northeast WI.  925mb temps will be falling below zero
in the evening, so some snow flakes may mix in with the rain over
the higher terrain areas of n-c WI.  Clouds will be slow to depart
within cyclonic flow on Thursday, but should see some clearing
arrive from west to east during the afternoon with the arrival of a
surface high.  This high quickly departs on Thursday night, with mid
and high clouds increasing once again.  No significant changes to

Rest of the forecast...Precip chances will increase again Friday
afternoon into Friday night as low pressure moves over the Upper
Peninsula region.  Temps will be warmer on Fri though due to the
warm advection regime ahead of the surface low.  Precip chances look
to end late Friday night for most of the area, except for north-
central WI where some wrap around showers could linger into
Saturday.  Then cool and dry weather conditions return for Sunday
before the next system arrives early next week.

.AVIATION...for 18Z TAF Issuance
Issued at 1241 PM CDT Tue Oct 25 2016

VFR conditions will continue through the evening hours, however
flying conditions are expected to gradually deteriorate from south
to north late tonight into Wednesday morning as a weak surface
low and mid-level trough approach from the southwest. Rain showers
are forecast to reach central and east-central Wisconsin before
daybreak and reach the U.P. of MI by mid-morning Wednesday. Once
the precipitation begins, cigs/vsbys will drop into the IFR range
with local LIFR condition under heavier bands of rain. The poor
flying conditions are expected to persist through the daylight
hours of Wednesday and may not improve until late Wednesday night.
In addition to the incoming rain, blustery conditions are expected
and have inserted LLWS into the TAF`s for late tonight/Wednesday
morning with wind speeds rapidly increasing just above the



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