Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 170323

Area Forecast Discussion
National Weather Service Sioux Falls SD
1023 PM CDT Sat Sep 16 2017

.SHORT TERM...(This evening through Sunday)
Issued at 338 PM CDT Sat Sep 16 2017

The frontal boundary has slipped just to the south and east of our
coverage area, with it currently running along a line from near
Omaha to Storm Lake to Minneapolis. Behind it, there remained just
enough elevated instability to allow for some drizzle/showers and
isolated storms during the morning hours that have since largely
voided the area. As the main trough and associated jet streak pivot
closer to the region later this afternoon and evening, could see
some re-enhancement of showers and storms closer to the boundary
across our far southeastern counties in northwest Iowa. With this
said, short range high res guidance is rather unimpressive with this
potential. Any activity that does fire in this area is not expected
to be severe behind the boundary. Otherwise, look for precipitation
chances ending, and clouds beginning to clear from west to east
through the evening hours.

Tonight`s temperature forecast is a bit tricky. With clearing skies,
decreasing winds and a chilly airmass now in place, expecting
temperatures to fall into the low 40s and perhaps even a few upper
30s out near the Missouri and James River valleys. Further east, mid
to upper 40s will be more common of low temperatures.

Sunday is expected to be quieter as surface high pressure sets up
over the area. Temperatures will rebound several degrees from
today`s highs into the mid 60s to low 70s but still remain generally
5-10 C below their climatological normals. Mid level clouds will be
on the increase by the late afternoon hours.

.LONG TERM...(Sunday night through Saturday)
Issued at 338 PM CDT Sat Sep 16 2017

Mid and long range forecast will be an active one, as a large closed
upper level low wobbles over the Pacific northwest, into the
northern Plains.

A shortwave lifts out of the Nebraska panhandle Sunday evening and
tracks into northeast Nebraska by daybreak Monday. Scattered showers
and non severe thunderstorms will move into the Missouri Valley in
the evening and spread across the area, mainly to the south of I-90
overnight. This spotty activity will continue into Monday morning,
then dissipate from west to east by afternoon.

Tuesday looks like a dry but windy day, with strong southerly flow
developing ahead of an approaching front and trough. With strong
mixing and gusty southerly winds, expect a warm day, with highs
around 80 to 85 degrees. Showers and thunderstorms will be possible
ahead of the boundary late Tuesday afternoon into Tuesday night.
Strong shear and good instability will bring the potential for a
severe weather threat, especially in the evening.

Wednesday and Thursday looks to be largely mild and dry out ahead of
the next shortwave to push into the northern Plains. Models are a
bit split on the timing of the frontal push into the region moving
into late week. Think that the timing of the blended pops is a bit
too bullish for Friday, so lowered the likelies to chances. Looking
at a better chance for Friday Night into Saturday.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1021 PM CDT Sat Sep 16 2017

Low clouds continue to pull off to the east through the late
evening, with VFR conditions through the TAF period.




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