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Area forecast discussion 
National Weather Service Sioux Falls South Dakota
633 PM CDT sun Sep 21 2014

Short term...(this evening through monday)
issued at 309 PM CDT sun Sep 21 2014

Receding short wave will bring a night of clear skies with
subsidence as high pressure moves across the area. Lingering
scattered clouds east will dissipate very early. Winds should be
light to calm including over the decoupled west as weak southerly
low level flow tries to get started. Despite the clear skies and
light to calm not see fog Worth mentioning on this day
before the equinox. Dry air should limit and very shallow fog to
isolated low areas including a few spots over relatively warm
lakes/ponds/rivers. General visibility should not suffer.
Temperatures will cool decently to the 40 to 45 range.

Monday will start clear ... high and eventually some middle
clouds will begin to increase from the west/southwest in the area
west of the James this mornings California upper low
approaches slowly through the upper ridge. Support moisture and
instability all far too weak to think about any showers extreme
southwest through the end of the day. Sunshine will rule east of the
James River. The southerly flow will increase slowly but steadily at
the surface but should stay below 10 miles per hour in southwest Minnesota and
northwest Iowa. High temperatures will show a tad of warming from
today with low to middle 70s.

Long term...(monday night through sunday)
issued at 309 PM CDT sun Sep 21 2014

The primary story in the medium and long term forecast is with an
upper level system moving into the northern plains by
Tuesday...and eventual development of long wave ridging over the
eastern half of the Continental U.S. By midweek.

Upper low currently over California/Nevada will slowly track
northeast...arriving in the northern plains by Monday night. Large
area of rain should form over Nebraska and south central South
Dakota Monday night...with this area of precipitation moving
northward into the area on Tuesday. Soundings indicate very limited feel the chances of thunder are relatively low.
Activity should be fairly scattered on Tuesday...and it will prove
difficult to pinpoint temperatures.

Rain should gradually dissipate by Wednesday morning as middle-level dry
air moves into the area. This upper low will gradually meander
through the plains for the remainder of the week...getting caught
under the larger synoptic ridge that will develop by mid-week.
However...moisture will become limited and in the end we should just
see a bit more diurnal cloud cover than usual. The biggest story
heading into next weekend will be the pleasant conditions and above
normal temperatures. Low-level temperatures will remain well above
normal...and will translate into high temperatures nearly 10
degrees above normal through Sunday.


Aviation...(for the 00z tafs through 00z Monday evening)
issued at 631 PM CDT sun Sep 21 2014

VFR conditions are anticipated through Monday. The only thing to
watch for is any reduced visibilities near sunrise Monday...
especially in northwest Iowa into the MVFR category. This
possibility was not included in the ksux taf as any fog will
development should be very patchy and shallow.


Fsd watches/warnings/advisories...
South Dakota...none.


Short term...
long term...dux

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