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Area forecast discussion 
National Weather Service Sioux Falls South Dakota
625 PM CDT sun Aug 2 2015

Short term...(this evening through monday)
issued at 254 PM CDT sun Aug 2 2015

Surface high pressure continues to sink southward this
afternoon...driving a frontal boundary into the middle-Missouri River
valley. The front is currently sitting just outside the County Warning Area
boundary...however moisture has pooled just behind the boundary.
With temperatures approaching 90 degrees...this is making for a
rather humid afternoon in the southern tier or two of counties.
Convection chances still appear minimal...or focused just outside of
the County Warning Area.

The overnight hours...for most areas...should be cloud free and cool
as temperatures fall either side of 60 degrees. Further
south...elevated 700 mb boundary remains just south of the County Warning Area over
northern/central Nebraska and west central Iowa. A few
showers/storms could develop along this boundary towards
daybreak...but any impact should remain south of the County Warning Area.

A quiet day is expected on Monday as surface ridging prevails.
Temperatures will hover around 80 degrees with light and variable

Long term...(monday night through sunday)
issued at 254 PM CDT sun Aug 2 2015

Monday night through the weekend will be noted by near to below
normal temperatures and fairly frequent shower/thunderstorm
chances. Both are due to the flattening/suppressing of the plains
upper ridge to the south by several short waves crossing the central
and northern plains. Precipitation chances will gradually push into
the area Monday night through Tuesday night as a weak wave cuts
across the middle of the ridge. Lingering northwesterly upper flow
on west side of major northern Great Lakes trough will make the
advent of rain chances slow into the northeast part of the region.
The entire area should see the threat by Wednesday. Models vary on
rainfall potential over the area with different treatments of this
wave. The NAM is modest...the GFS is gung Ho...and the Gem/Canadian
lets the wave slip much further south with little rain over the
area. The modest approach on amounts seems best for now. Nighttime
temperatures will be fairly close to normal while daytime highs will
definitely be on the cool side.

Another wave is pegged to come across the area Thursday with a
system coming across on a track further north by Friday. This
northern wave seems strong enough to force some ridging behind it
and lead to a dry day or so...which seems targeted for Friday night
and Saturday right now. Then another system approaches in the
progressive flow by Sunday with another rain threat.

The cool days and normal to slightly cool nights theme should
continue through all of this.


Aviation...(for the 00z tafs through 00z Monday evening)
issued at 625 PM CDT sun Aug 2 2015

VFR conditions expected to prevail through the period...though will
have to watch for patchy MVFR-IFR shallow fog toward daybreak Monday
as surface ridge brings light winds to the area. Have not included
in tafs at this time...but most likely location would be in ksux
where boundary layer mixing was most limited during the day today.


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


Short term...dux
long term...

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