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Area forecast discussion 
National Weather Service Green Bay WI
1057 PM CDT Sat Jul 12 2014

Updated aviation portion for 06z taf issuance

Short term...tonight and Sunday
issued at 337 PM CDT Sat Jul 12 2014

Showers and thunderstorms are the main concern during this part of
the forecast.

A weak cold front across north central Wisconsin has moved little
during the day. This front was forecast to make it about Half Way
through the area before weakening and dying. Dew points across the
area were mostly in the middle 60s to around 70 degrees. MUCAPE
values were in excess of 1000 j/kg across parts of north central
Wisconsin by midday...with little to no cin...and there was some
upper level divergence associated with a 300mb jet maximum. But it
took until early this afternoon before some short wave energy
pushed eastward and convection reached the western part of the
forecast area. Expect showers and thunderstorms to continue to
push eastward during the late afternoon and evening with the
passing short depicted by hrrr. 12z grb sounding had precipitable water
of 1.51 inches so heavy rainfall is possible with storms. Models
were generally dry overnight and on Sunday. A cold front...that
was moving into North Dakota this afternoon...will push through
the area on Sunday and bring drier and much cooler air into Wisconsin.

Long term...Sunday night through Saturday
issued at 337 PM CDT Sat Jul 12 2014

The much publicized cold upper low will approach
northern Wisconsin late Sunday night. Showers are possible in
the north towards daybreak. The upper low then is forecast to move
slowly across the northern Great Lakes Monday and Tuesday. The GFS
is faster in moving the system through the region than the European model (ecmwf).
Cold temperatures aloft and cyclonic flow should make for considerable
shower activity Monday and to a lesser degree Tuesday. 850mb temperatures
are forecast to drop to around 4 to 6 c by Monday afternoon and continue
through Tuesday. This should result in high temperatures in the upper
50s to middle 60s Monday and Tuesday and break a few low maximum
temperature records. Low temperatures will not get than cool due
to cloud cover and at least some wind. High pressure builds in
Wednesday and Thursday with pleasant Summer weather. There is a
small chance of showers Friday or Saturday as southerly flow
brings moisture northward from the Southern Plains. Think the air
will be sufficiently dry in the low levels to keep precipitation
away until Saturday night or Sunday.

Aviation...for 06z taf issuance
issued at 1053 PM CDT Sat Jul 12 2014

Showers will be east of the region by taf issuance time...although
a secondary cold front may bring isolated rain showers back into NC WI overnight.
Of greater concern is the area of low clouds that has developed over
parts of northwest/NC WI. Expect these low clouds to expand eastward...and
bring IFR ceilings to the rhi/auw/cwa taf sites overnight and possibly
into early Sunday morning. For now...will only mention scattered low clouds
at the eastern WI taf sites. The low clouds should mix out by
mid-morning...followed by VFR conditions for the rest of Sunday
and Sunday evg. West winds will gust to near 20 kts during the
late morning and afternoon.

Grb watches/warnings/advisories...


Short term.....Mg
long term......rdm

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