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000
FXUS63 KGRB 171138
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
638 AM CDT Sat Jun 17 2017

Updated aviation portion for 12Z TAF issuance

.SHORT TERM...Today...Tonight...and Sunday
Issued at 356 AM CDT Sat Jun 17 2017

The main area showers and thunderstorms shifted east of the region
as a short-wave trof exited early this morning, but isolated
showers persisted due to the arrival of the LFQ of an upper jet
streak. Models suggest that much of the day will be fairly quiet,
followed by scattered showers and thunderstorms developing over
mainly north central WI as a weak cold front approaches late in
the afternoon. Severe weather chances look minimal, as CAPE is
only forecast to be 500-1000 j/kg. Abundant cloud cover will hold
temperatures back a bit, with highs only reaching the upper 70s
and lower 80s.

Shower and thunderstorm chances will ramp up tonight as a potent
short-wave trof and the LFQ of a strong jet streak move through
the region. Have bumped pops up to categorical north, and likely
south during the overnight hours. Instability is expected to be
quite weak by the time the best dynamics arrive, so severe weather
is unlikely. Low temperatures should range from the middle 50s
northwest to the lower 60s southeast.

On Sunday, another short-wave trof and a secondary cold front will
move through the region and trigger numerous showers and scattered
thunderstorms. Small hail will likely accompany any storms. CAA,
clouds and showers will result in cooler temperatures, ranging
from the middle 60s northwest to the lower to middle 70s
southeast.

.LONG TERM...Sunday Night Through Friday
Issued at 356 AM CDT Sat Jun 17 2017

Flow aloft starts out cyclonic over the Great Lakes at the start
of the work week. Once the main trough axis passes east of
Wisconsin the flow becomes northwest before backing to a more
zonal pattern and then southwest during the latter half of the
week. High temperatures are expected to be several degrees below
normal on Monday and Tuesday before a warming trend brings near
normal highs to the area for Thursday and Friday.

Cyclonic, followed by relatively low amplitude flow aloft will
bring chances for showers and storms to some part of the forecast
area for much of the upcoming work week. The best chance for a
period of dry weather looks to be Tuesday night through Wednesday
with surface high pressure over the Great Lakes and a weak mid
level ridge passing through the area.
&&

.AVIATION...for 12Z TAF Issuance
Issued at 633 AM CDT Sat Jun 17 2017

VFR conditions and generally quiet weather are anticipated across
the region during the day, though scattered showers and storms
may develop near a weak cold front in north central WI late in
the afternoon. Showers and scattered thunderstorms will increase
across the region tonight, as a strong upper level disturbance
moves through. Ceilings are expected to lower to MVFR/IFR over
north central and central WI late, and visibilities will be
reduced at times due to steadier/heavier rainfall.

&&

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

$$

SHORT TERM.....Kieckbusch
LONG TERM......MG
AVIATION.......Kieckbusch