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Area forecast discussion 
National Weather Service Sioux Falls South Dakota
629 PM CDT Monday Sep 1 2014

Short term...(this evening through tuesday)
issued at 355 PM CDT Monday Sep 1 2014

Isolated storms in the eastern County Warning Area primarily diurnally driven and
should diminish toward sunset. Farther west...upper wave tracking
out of the western High Plains will continue to spark mainly middle
level based thunderstorms as it moves east across the forecast area
overnight. While most storms should remain below severe limits...
with relatively dry sub-cloud layer...cannot rule out isolated
stronger wind gusts into the early evening. With expected cloud
cover as the wave moves through...bumped up lows a bit from previous
forecast...with middle to upper 50s expected in most areas.

Showers/thunderstorms should exit the eastern County Warning Area early Tuesday
morning...followed by mostly sunny skies and mild temperatures
warming into the upper 70s to lower 80s.

Long term...(tuesday night through monday)
issued at 355 PM CDT Monday Sep 1 2014

Middle level warm air advection develops Tuesday night...allowing
clouds to increase from the south overnight. Could see enough weak
convergence to trigger some isolated showers and perhaps a few
rumbles of thunder across our western and northern forecast
area...mainly late at night into Wednesday morning as the low level
jet noses into south central South Dakota and a weak middle level
impulse lifts northeast into the area. With some decent warming and
breezy southerly winds dominating Wednesday...temperatures will warm
significantly in our west...approaching highs near 90. Further
east...temperatures will also improve improve into the middle to upper
80s...but could be tempered some by residual middle level clouds into
the afternoon hours.

Surface low deepens over the central Dakotas Wednesday night and
lifts into northern Minnesota Thursday afternoon as an upper trough
skims the North Dakota and Canadian border. Isolated warm air
advection showers and thunderstorms will again be possible across
our northeastern half...mainly in the late afternoon and evening on
Wednesday. A cold front tracks east across the forecast area during
the day on Thursday...bringing another chance of showers and
thunderstorms along with the front...mainly in the evening across
northwest Iowa and adjacent counties. Still quite a bit of
uncertainty in the timing and location of this front...with the Gem
dropping the front much further south than the other
models...and well away from the forecast area on Thursday.

Surface ridge expands into the region Friday through
Sunday...leading to some pleasant...cool and dry weather conditions.
Highs will drop well below normal...only topping out in the upper
60s and lower 70s on Friday and Saturday...and improving a few
degrees on Sunday. Models diverge signficantly early next
week...with the GFS developing some strong warm air advection into
western and central South Dakota and some scattered showers and
thunderstorms as early as Sunday night. Confidence remains low
however...given the much drier pattern seen in the European model (ecmwf).

&&

Aviation...(for the 00z tafs through 00z Tuesday evening)
issued at 611 PM CDT Monday Sep 1 2014

Scattered convection developing over central South Dakota will
move eastward overnight...affecting the taf sites in the evening
hours. May see patchy fog development later at night around kfsd
and ksux after showers end with light winds situated across the
area.

&&

Fsd watches/warnings/advisories...
South Dakota...none.
Minnesota...none.
Iowa...none.
NE...none.
&&

$$

Short term...
long term...
aviation...jm

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