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fxus63 kfsd 212241 

Area forecast discussion
National Weather Service Sioux Falls South Dakota
541 PM CDT Sat Sep 21 2019

Short term...(this evening through sunday)
issued at 314 PM CDT Sat Sep 21 2019

As of early afternoon, distinct boundary near the Highway 60
corridor in southwest Minnesota/northwest IA, with line of showers and
embedded storms largely confined to the boundary. Model soundings
depict slight capping inversion around 800-750mb, which is likely
holding back deep convection to this point, but should storms break
through this inversion, plenty of instability with steep mid level
lapse rates, along with effective shear values near 40kt, so cannot
rule out isolated severe hail as storms progress through our far
eastern counties late this afternoon.

Boundary and any associated storms are expected to be east of our
County Warning Area by 22/00z, so remainder of the night should be rather quiet,
though will see increasing mid-level clouds from the southwest as
subtle wave approaches in the southwest flow aloft. This wave
induces mid-level frontogenesis across our southeast counties
Sunday, resulting in a chance of mainly light showers, with
instability quite limited. Temperatures tonight/Sunday will be
closer to normal, with lows tonight in the 50s, and highs Sunday
mainly upper 60s to lower 70s.

Long term...(sunday night through saturday)
issued at 314 PM CDT Sat Sep 21 2019

Temperatures on a bit of a roller-coaster as we head into the
astronomical fall season this week. Strong push of warm advection
Monday night will help push temperatures back into the upper 70s to
mid 80s Tuesday, accompanied by only a modest increase in humidity.
This could lead to a chance of storms in our eastern counties by
late afternoon/evening Tuesday as the cold front pushes through,
with a few showers dropping in from the northwest as the trailing
wave slides through late Tuesday night/early Wednesday.

Cooler, but still seasonable temperatures settle in midweek behind
the wave, with highs Wednesday mid 60s-lower 70s. Wednesday night
should be the coolest night of the week, with high pressure and
clearing skies allowing readings to cool into the 40s many areas.

Another surge of warm air and moisture advection builds into the
area late this week. Another round of scattered showers and storms
possible with warm advection and increasing low level jet Thursday
night, and a chance of rain continuing into Friday as the trailing
cold front pushes east. While overall pattern shift late this week
into early next week appears to favor above normal temperatures, day
to day high temperatures will be largely dependent on the timing of
various waves, so low confidence to change blended guidance in one
direction or the other at this point.


Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 538 PM CDT Sat Sep 21 2019

VFR conditions expected through the taf period. A few showers
will be possible over parts of northwestern Iowa on Sunday morning,
though impact to ksux will be minimal.


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

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