Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 052150
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
350 PM CST Tue Dec 5 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 347 PM CST Tue Dec 5 2017

Additional light snowfall is expected this evening and overnight for
much of the area as a weak vorticity maximum rotates around the
large upper-level trough centered over the Great Lakes and
eastern U.S. Although this system is not overly impressive, a band
of low-level frontogenesis looks to set up in a northwest-to-
southeast-orientation roughly from Chamberlain and Huron to
Yankton, SD. These and other locations west of I-29 in SD have the
best chance of seeing another inch or so of new snow. High
resolution models hint that a narrow, 20-mile-wide corridor along
the front near Mitchell, SD could get up to 2 or 3 inches of new
snow, but given the small scale of this near-surface feature,
confidence remains low on the exact location. Southwest MN and
northwest IA could see a flurries and even light accumulations
tonight, but these are forecast to be less than half an inch.

Wednesday will be another breezy and cool day, with temperatures a
few degrees cooler than Tuesday. The weak front from the past
night with associated light snowfall should move south of the
region during the afternoon, but south central SD could see
periods of snow linger through early afternoon hours.


.LONG TERM...(Wednesday night through Tuesday)
Issued at 347 PM CST Tue Dec 5 2017

Winds will continue to be breezy from the northwest for the
remainder of the work week. The overall weather pattern will change
little over the next 7 days, with a massive upper level trough over
the eastern CONUS and an amplified ridge over the West Coast. This
will keep the tri-state area under the influence of the meridionally
oriented jet stream with occasional weak shortwaves moving through.
Each of these systems could bring very light snow to the region, but
the exact timing of waves remains low confidence given model spread.
That being said, Monday into Tuesday currently looks like the next
opportunity for more widespread snow, as a more distinct shortwave
pushes southward.

Temperature-wise, the rest of the work week looks cool, with high
temperatures about 5 to 10 degrees below seasonal normals. Thursday
morning looks to be the coldest timeframe, with partly clear skies
and single digit overnight lows. Over the weekend, the upper level
ridge briefly nudges east, bringing a slight change to westerly flow
and temperatures close to normals by Sunday and Monday. Colder than
average temperatures are quick to return by Tuesday of next week.


&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1150 AM CST Tue Dec 5 2017

Northwest winds will continue to gust in the 20 to 30 kt range
during the daylight hours today. Overnight, low level cloud decks
will develop, along with a possibility for a few hours of light
snow. KHON has the best chance of additional snow accumulations, but
these should stay under an inch. Breezy conditions return after
sunrise Wednesday, with any lingering snow showers ending by the
afternoon.


&&

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

$$

SHORT TERM...VandenBoogart
LONG TERM...VandenBoogart
AVIATION...VandenBoogart



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