Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 161726
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1126 AM CST Sat Dec 16 2017

.SHORT TERM...(Today and Tonight)
Issued at 346 AM CST Sat Dec 16 2017

Fairly thick high and mid-clouds are expected today, but should be
another mild day with 925 hpa temps continuing to remain above 0C.
Weak northerly flow will allow slightly cooler air to filter into
the region from the north, so expect thermal gradient from north to
south throughout the day.

Models have backed off on precipitation chances for tonight, and
have dried out the forecast. With that said, some models hint at the
potential for stratus.  Low lying stratus appears to be thickest
across the central portion of the state.  There is still a remote
chance at some drizzle if the stratus is able to induce
collision/coalescence. Confidence at this point is not strong enough
to include in the forecast given the lack of dynamics.

.LONG TERM...(Sunday through Friday)
Issued at 346 AM CST Sat Dec 16 2017

Mild temperatures continue into the first half of next week.  Models
still suggest a mid level trough moving from the Pacific NW into the
plains on Thursday.  With fairly good agreement of a system amongst
the various solutions, raised pops across northwest Iowa by blending
Superblend and CONSALL.  With that said, still quite a bit of
differences in duration and precipitation amounts. GFS is fairly
light and transient, while the ECMWF suggests a longer duration
system, but both models take the crux of mid level energy and focus
it well to the south. It is interesting to note that ECMWF continues
to trend further south with each model run iteration.  Upper level
dynamics certainly increase Thursday night into Friday, just a
question of how this will match with what is occurring closer to the
surface. It appears however, that once the cold air pours into the
area on Wednesday night into Thursday, the region will be much
cooler heading into the weekend and even the following week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1121 AM CST Sat Dec 16 2017

Widespread overcast conditions expected by tonight, with MVFR
ceilings expected at each TAF site during portions of the forecast
period. Some hint that northeasterly flow will advect in some of
the IFR ceilings seen currently over Minnesota, impacting FSD and
SUX tonight. Did not place these ceilings into the TAF sites due
to low confidence, but will continue to monitor.

&&

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

$$

SHORT TERM...BT
LONG TERM...BT
AVIATION...Ferguson



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