Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 220821

Area Forecast Discussion
National Weather Service Sioux Falls SD
321 AM CDT Sun Oct 22 2017

.SHORT TERM...(Today and Tonight)
Issued at 320 AM CDT Sun Oct 22 2017

A surface ridge situated across the Central Plains will shift to the
east today, and with that we will see our winds shift around to the
southwest by afternoon. In response, it will be another very mild
day over south central SD and the James River and MO River Valleys,
with highs topping out close to 70. Back to the east, temperatures
will trend downward somewhat with highs in the mid 60s.

For tonight, upper level energy begins to dive southward into the
Northern Plains while a cold front swings through the area. With
that, winds will turn around to the northwest and begin to pick up
after midnight. Models hinting at the possibility of some very light
rain/sprinkles north of I-90 later in the night with the system. In
spite of ensuing cold air advection, temperatures will remain in
check overnight with increasing clouds and wind, with lows dropping
into the lower to mid 40s.

.LONG TERM...(Monday through Saturday)
Issued at 320 AM CDT Sun Oct 22 2017

On Monday upper level energy continues to drop southward as a trough
deepens over the central CONUS. A secondary more significant cold
push comes through in the afternoon, and with cold air advection and
winds of 40 to 45 kts at the top of the mixed layer, northwesterly
winds will continue to pick up through the day. Had to increase wind
speeds above given Superblend guidance, and an eventual Wind
Advisory is likely for Monday afternoon. Does appear to be enough
forcing that a few light showers could develop over portions of east
central SD and southwestern MN in the afternoon, though moisture is
pretty limited. Highs should top out in the upper 50s to lower 60s,
though could see temperatures cooling in the afternoon over portions
of our north central and eastern CWA with the increasing clouds and
cold air advection.

With the passage of the system and the upper level trough continuing
to deepen over the east central part of the Nation, Tuesday will be
a much cooler day with highs in the upper 40s to mid 50s. Winds will
again be strong out of the northwest. The cooler air will be short
lived however, as shortwave ridging slides across the area on
Wednesday and temperatures rebound into the 60s.

Big changes in store for the end of the week as another upper level
trough deepens over the central CONUS. There are still some model
differences in timing/track of features, though all trend toward a
cooler solution for Thursday into the weekend with below normal
temperatures through the period. By Thursday night and Friday
thermal profiles would be cold enough to support snow if we get any
precipitation, through models vary greatly, with the GFS much more
aggressive in bringing precipitation to the area during that time
frame- while the ECMWF portrays almost none. What does look more
certain is a very windy period for both Thursday and Friday with
strong northwesterly winds.


.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1040 PM CDT Sat Oct 21 2017

VFR conditions will prevail through the period. Southwest winds
could become briefly gusty Sunday afternoon 18Z-23Z, though gusts
will remain below 25kts. Otherwise expecting winds at or below




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