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Area forecast discussion 
National Weather Service Sioux Falls South Dakota
1055 PM CDT Thursday Jul 30 2015

Short term...(this evening through friday)
issued at 306 PM CDT Thursday Jul 30 2015

Another nearly perfect afternoon across the tri-state area as skies
remain clear...temperatures hover in the 80s...and winds are very
light. These pleasant conditions will continue overnight as a very
weak frontal boundary sinks through the area. Much like last
night...expecting very patchy valley fog with temperatures falling
into the 50s and low 60s.

Friday will be a tad warmer again...with seasonal humidity levels in
the 30-40 percent range. There may be slightly more daybreak cloud
cover...but for the most part Friday will be sunny. Best chanced
for convection will be focused along a weak convergence zone across
north central and central Nebraska.

Long term...(friday night through thursday)
issued at 306 PM CDT Thursday Jul 30 2015

Friday night and Saturday looks to bring a gradual buildup of
instability and moisture to accompany a favorable upper flow for
scattered storms to develop and potentially become severe. Expect
the bulk of these storms over the southeast half of the area late
Saturday and Saturday response to the heating and best
moisture with the analysis in this mornings Storm Prediction Center day 3 outlook
seeming very reasonable. The low levels don't seem to present a
tornado threat and damaging winds would likely be spotty...but some
fairly big hail could develop. A marginal risk looks very good right
now given the hint at an upgrade when details become firmer closer
to the period.

High temperatures Saturday look like middle 80s to lower 90s.
Humidity will pick up a bit. Saturday morning lows will still be
in the upper 50s to lower 60s with the fairly light winds. With
the increasing moisture...early Saturday morning golfers will
likely have plenty of dew to sweep. Will not put any fog in the
grids as anything should be local and quite shallow.

Very weak high will help bring some drying for Sunday and there
seems little to initiate any storms so will keep the forecast dry
despite a weak approaching low level trough. The passage of this
trough will bring a gradually developing easterly flow and slow
cooling trend next week after a warm Sunday. Now having some
confidence in this cooling trend with the models gradually nudging
the main upper ridge to the south. The ec does this more than the
GFS...but even the GFS is no longer trying to build the ridge into
the northern plains to bring a hot weather spell. The low and middle
level flow resulting and an influx of moisture should bring a threat
of storms to the area during the week...though lack of a decent
upper system would seem to Nix the threat of a significant wet
period. Below normal high the 70s over the area by
next Thursday...look good.


Aviation...(for the 06z tafs through 06z Friday night)
issued at 1055 PM CDT Thursday Jul 30 2015

VFR conditions are expected to dominate into Friday evening. However
lingering near surface moisture could result in patchy valley fog
late tonight toward sunrise. Confidence is low that any fog will
affect Airport/taf locations...but did include tempo IFR visibility
at ksux toward daybreak where near-surface saturation is more
favorable. Winds will remain light and variable through the period.


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


Short term...dux
long term...

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