Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 262327

Area Forecast Discussion
National Weather Service Sioux Falls SD
627 PM CDT FRI AUG 26 2016

.SHORT TERM...(This evening through Saturday)
Issued at 324 PM CDT Fri Aug 26 2016

The main changes to the forecast will be an overall decrease in
precipitation chances. At this time the trends from overnight into
the current model runs are that precipitation will likely remain to
the south and east of the area. While some light rain still remains
a possibility, the chance for a more widespread moderate rain is
unlikely. The main culprits appear to be deeper instability along
the surface to 925mb boundary which is closer to southeast Nebraska
into southern Iowa, little to no instability along the mid level
front and some drying in the mid levels. Suspect that there will
still be quite a bit of cloud cover and with the upper level wave
moving through late tonight spotty light rain and very isolated
thunderstorms will still be possible.

Saturday will see gradual clear from southwest to northeast as the
upper level low moves through northeast SD. Will maintain the low
threat for showers and isolated thunderstorms along highway 14 as
this low passes.

.LONG TERM...(Saturday night through Friday)
Issued at 324 PM CDT Fri Aug 26 2016

On Saturday night the upper low to the north continues to shift off
to the east.  Despite the unstable environment, have kept the
forecast dry with lack of any trigger across the region. Have raised
forecast lows into the low and mid 60s with low level moisture
hanging around the area.

On Sunday, models hint at a series of disturbances moving from west
to east mainly south of the forecast area.  Disturbances appear to
be very convectively driven, so am a little suspect of their
validity.  Regardless, models keep chance of precipitation south of
the area till Sunday night.

Monday and Tuesday an upper level ridge builds into the northern
plains. Have raised forecast highs into the upper 80s and lower 90s.
Could see a few nocturnal storms mainly east of I-29 Monday and
Tuesday night as low level jet develops across the eastern half of
the forecast area.

Wednesday, a wave moves across knocking the ridge back temporarily.
Timing still appears late enough in the day that temps will be warm
on Wednesday.  Thursday into Friday looks warm with relatively dry
conditions as upper level ridge builds back into the region.


.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 620 PM CDT Fri Aug 26 2016

VFR will likely prevail through 06Z Saturday. However after 06Z,
it is anticipated that conditions will deteriorate as an upper air
disturbance moves across the area. First of all, left the mention
of rain chances out of the TAF sites and it appears too stable for
thunderstorms. Thoughts are that potential fog formation may be a
bigger issue for the TAFs later tonight then any rainfall. KSUX
could certainly drop into IFR conditions before Saturdays sunrise,
and possibly go even LIFR for a brief period of time right after
sunrise. KFSD should see some widespread MVFR conditions late
tonight and Saturday morning, with some possible MVFR fog near
sunrise at KHON. By late morning and midday and Saturday, all
sites should be VFR again.


.FSD Watches/Warnings/Advisories...


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