Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 151121

Area Forecast Discussion
National Weather Service Sioux Falls SD
521 AM CST Fri Dec 15 2017

.SHORT TERM...(Today and Tonight)
Issued at 302 AM CST Fri Dec 15 2017

Weak isentropic lift across southwest Minnesota on the 295K surface
leading to some very light precipitation across the eastern CWA.
This precipitation is mainly falling as snow, though forecast
soundings hint at potential for brief lack of saturation on the
dendritic layer and have seen a few surface obs reporting unknown
precip. Short term hi-res models suggest these flurries will work
east of the forecast area by late morning. Band of stratus extending
well back to the north and west will make it difficult for skies to
clear across the eastern half of the forecast area.  Further to the
south and west, should see skies at least become partly cloudy and
expect temperatures to respond by warming to levels 10-15 degrees
above normal.

Relatively mild conditions expected to continue into tonight with
flow becoming more westerly. With 925 hpa temps above freezing, lows
should only be a few degrees away from seasonal highs this time of

.LONG TERM...(Saturday through Thursday)
Issued at 302 AM CST Fri Dec 15 2017

Mild conditions continue into Saturday. Cold front is expected to
work through the region on Saturday, with cooler air working in
from the north. Models have some small pops across Central South
Dakota behind the front, but with little in the way of lift or mid
level forcing, lowered limited pops along a Chamberlain to Huron

Cooler temperatures are expected on Sunday, but will only last for a
day before we warm back to well above normal levels for the first
half of next week.

Most active portion of the forecast continues to be next Thursday as
strong cold front works through the region.  Models are both kicking
out precipitation, with the ECMWF more wet than the GFS.  Have
raised winds closer to MOS guidance around this system. Forecast
soundings look to support snow with this system, with the potential
for a deep dendritic layer near the surface.  Dynamics look to be
focused in the lower part of the atmosphere for the first half of
the event, possibly getting some help from the upper jet Thursday


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 521 AM CST Fri Dec 15 2017

VFR is expected across the Sioux Falls forecast area for the 12Z
TAF period.




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