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Area forecast discussion 
National Weather Service Twin Cities/Chanhassen Minnesota
646 am CDT Tuesday Sep 16 2014

Update...for 12z aviation discussion below


Short term...(today and tonight)
issued at 310 am CDT Tuesday Sep 16 2014

Surface high pressure will dominate the region through the
short-term period...and result in benign weather through tonight.

After a chilly start to the morning with areas of frost over parts
of west central Wisconsin...a light southwest wind will develop and
temperatures will moderate to around 5 degrees warmer than observed
readings on Monday.

Clear skies continue into tonight and winds become light and
variable. Looks to be more of a potential fog situation than
frost...with low temperatures ranging from 40 to 50 degrees and prognosticated
dew point depressions around 1 degree. Have included areas of fog in
the forecast for areas generally along/north of Interstate 94.

Long term...(wednesday through monday)
issued at 310 am CDT Tuesday Sep 16 2014

Few changes Wednesday through Thursday night with only minor adjustments to
temperatures Wednesday night/Thursday with a backdoor cold front moves southward
across the western Great Lakes.

The mean pattern has an upper ridge moving across the upper
Midwest Thursday night/Friday. Return flow on the nose of this upper
ridge...may allow for a few rain showers/thunderstorms and rain to develop late Thursday
night/Friday. But chances remain low due to the proximity of the
low level jet/thermal ridge. Late Friday/Saturday will see big changes across
the region as a positive long wave trough and associated height
falls/surface front moves across the area. Some minor differences
remain in the quantitative precipitation forecast fields...but precipitation remains favorable for
late Friday night/Saturday morning. Differences arise Saturday
afternoon/evening as the latest ec has a much deeper upper low
developing/moving southeast across the western Great Lakes compared to
the GFS/Gem. However the ensemble mean of the GFS does show some
similarities to the deeper solution of the ec. Basically this
means that the precipitation may linger longer across the eastern
County Warning Area Saturday night/Sunday morning before the mean upper low moves
southeast of our region.

This deepening of the upper low and associated digging of the long
wave trough across the eastern U.S. May hold off the warm up for
early next week. It still remains favorable for much warmer temperatures
for the week of 22nd. may be delayed a day or so if
the stronger ec is correct.


Aviation...(for the 12z tafs through 12z Wednesday morning)
issued at 646 am CDT Tuesday Sep 16 2014

High confidence in VFR conditions with sunny skies through this
evening...and then light winds and clear skies could bring fog to
parts of west central WI overnight. Have included MVFR ceilings at
Keau...and kept other sites VFR for now. Southwest winds increase
to between 7 and 10kts for the day...then become light and
variable this evening. concerns.

/Outlook for kmsp/
Wednesday...VFR. Winds vrb 5 kts.
Thursday...VFR. Winds southeast at 10-15 kts.
Friday...VFR likely. Slight chance MVFR with -shra. Winds S-SW
10-20kts g 25kts.


Mpx watches/warnings/advisories...
WI...frost advisory until 8 am CDT this morning for wiz016.



long term...jlt

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