Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 121730

Area Forecast Discussion
National Weather Service Sioux Falls SD
1130 AM CST Tue Dec 12 2017

.SHORT TERM...(Today and Tonight)
Issued at 346 AM CST Tue Dec 12 2017

After a very cold morning, temperatures will recover today with warm
air advection in an evolving westerly flow. Mid to low clouds will
spread across the area from west to east during the day with the
warm air advection aloft. The better warming will be realized over
our west, and with possible afternoon sunshine highs will make it
into the lower 50s over south central SD, to mid/upper 40s through
the James River and MO River Valleys. To the east where cloud cover
will exist for much of the day, looking at highs in the 30s.

Tonight, an upper level shortwave drops out of Canada and into our
area overnight, while a surface low tracks from ND to southern MN
during the night. This will pull a cold front through our area by
Wednesday morning. Related to that, northwesterly winds will begin
to pick up the latter half of the night. This will result in a much
milder night, and with the better mixing temperatures will rise
later in the night. Early night lows will range from the upper 20s
east to mid 30s over south central SD.

.LONG TERM...(Wednesday through Monday)
Issued at 346 AM CST Tue Dec 12 2017

Winds will continue to increase during the day on Wednesday behind
the front, with mixed layer winds of 40 to 45 kts, and may be
looking at another Wind Advisory. Models are still producing some
light precipitation with this system, more so over southwestern MN,
and thermal profiles support snow, with rain mixing in as
temperatures rise into the upper 30s to lower 40s. In any event, any
snow that would accumulate would be less than half an inch - again,
mainly over southwestern MN.

The shortwave train continues on Thursday as another wave slides
southward on a northwesterly upper level flow. As is typical with
these type of systems, models varying a bit in placement of the
feature - and associated light precipitation - but consensus would
lean more toward areas west of Interstate 29, and could see a near
half an inch of snow over that area, before mixing with rain in the

No surprises in the longer term - Friday through Monday - with
pretty much the status quo characterized by above normal
temperatures through the period. Model differences do not bring
confidence to any precipitation timing, though the overall theme
will be for mainly dry conditions into the beginning of next week.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1117 AM CST Tue Dec 12 2017

VFR conditions are expected through the afternoon and evening
hours today. Could be some LLWS later this evening and overnight
as stronger winds move in above the ground. Northwest winds will
increase through the morning hours Wednesday with some gusts up to
35 kts by daybreak. MVFR stratus will also begin to nudge into the
the area by late in the TAF period with some light precipitation
possible across SW Minnesota.




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