Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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689
FXUS63 KFSD 140451
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1051 PM CST Wed Dec 13 2017

.UPDATE...
Issued at 546 PM CST Wed Dec 13 2017

Wind Advisories across the area have been cancelled, as winds
have decreased below criteria, and will continue to decrease
through the evening. Nevertheless, north wind gusts to around 35
mph will continue to be possible through midnight.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 259 PM CST Wed Dec 13 2017

Strong winds from early Wednesday continue to slowly subside this
afternoon, and will gradually trim back wind advisory through the
afternoon.  For the most part, the CWA has stayed dry through the
afternoon. May continue to see a bit of light flurries or perhaps
very light drizzle or freezing drizzle in the Buffalo Ridge areas
into the very early evening hours. Traffic cameras are not showing
any impact in the CWA, but are picking up a bit of lower ceilings
and precipitation into NERN South Dakota. However impacts are
anticipated to be minimal if any as temperatures hold near or above
freezing.

The primary forecast concerns over the upcoming 24 hours are
focused on light snow chances arriving late tonight and continuing
through Thursday. Yet another shortwave moving through northern
Alberta this afternoon will track nearly due south on Thursday
across the Western Dakotas. Lift is not overly impressive with
this wave, but should be sufficient to produce an area of light
snow. Snow should begin in areas along the Missouri River Valley
in central South Dakota near or after daybreak, with a secondary
area of light precipitation spreading eastward into MN/IA by mid-
day and the afternoon. Accumulations should stay on the light end
of guidance given warming temperatures. Could see upwards of an
inch of snow in areas west of a line from Huron to Mitchell and
Lake Andes. Further east, only a dusting to a couple tenths of
snow are anticipated.

.LONG TERM...(Thursday night through Wednesday)
Issued at 259 PM CST Wed Dec 13 2017

A fairly high degree of cloud cover, combined with westerly winds
will hold temperatures in the 20s for Thursday night.

Shortwave ridging moves overhead for Friday, producing a breezy
southwesterly surface wind. Should see temperatures try to climb
into the lower 40s in the afternoon.

A larger upper trough begins to move towards the Northern Plains
late Friday into the upcoming weekend. There continues to be a few
model differences, but the overall consensus keeps the area dry with
above normal temperatures Friday night and Saturday with a weak warm
front focusing light snow well northeast of the CWA.

A split in the upper flow pushes a wave of energy into the Four
Corners region, with a weaker trough passing through the northern
stream along the Canadian Border late on Saturday.  The end result
will be a trend towards drier conditions on Sunday as only weak mid-
level frontogenesis passes southeast across the Tri-State region.

Little to no change in the forecast for next week as the area
remains stuck in slight northwesterly flow aloft and on the edge of
a somewhat suppressed ridge over the western CONUS. The end result
will be a continuation of above normal temperatures and dry
conditions through at least Wednesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1050 PM CST Wed Dec 13 2017

Intermittent flurries are possible along the I-29 corridor through
the overnight hours, but very little if any accumulation is
expected. Tomorrow morning, a system will move south, bringing a
round of light snow. The largest accumulations of around an inch
are expected west of I-29. Ceilings and visibilities will lower
during periods of snow, with MVFR conditions likely and brief IFR
conditions possible. Winds will be light, gusting in the 15 to 20
kt range, with snow ending around 15/0200z for most locations.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&

$$

UPDATE...VandenBoogart
SHORT TERM...Dux
LONG TERM...Dux
AVIATION...VandenBoogart



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