Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 101108

Area Forecast Discussion
National Weather Service Sioux Falls SD
508 AM CST Sun Dec 10 2017

.SHORT TERM...(Today and Tonight)
Issued at 318 AM CST Sun Dec 10 2017

An upper level trough presently centered over the Ohio Valley will
shift eastward today while upper level ridging to our west nudges
into our area. With that, temperatures will warm a good 10 to 15
degrees over yesterday, with highs in the upper 30s over
southwestern MN to mid 50s over far south central SD.

Low pressure over south central Canada drops into the Upper
Mississippi Valley by late tonight, driving a cold front into our
area by Monday morning. With a tightening gradient and ensuing cold
air advection, northwesterly winds will begin to increase late
tonight, and because of that temperatures will steady out or rise
overnight. Lowest readings early in the night will range from the
mid 20s to lower 30s.

.LONG TERM...(Monday through Saturday)
Issued at 318 AM CST Sun Dec 10 2017

The cold front sweeps through the region on Monday, and it will
become windy in a tight gradient and winds at the top of the mixed
layer running around 40 to 45 kts, resulting in the potential for
near Wind Advisory criteria at times, so will be something to watch
for in future forecasts. May squeeze out a little moisture with the
frontal passage, so cannot rule out some very light rain/snow during
the day, but any accumulation would be minimal. While there will be
a general cool down on Monday, readings will still be above normal
with highs mid 30s to lower 40s.

This will lead to slightly cooler temperatures with less wind on
Tuesday. Another shortwave drops southward on the northwesterly
upper level flow on Tuesday night into Wednesday, though models in
disagreement on the track of this system, with the ECMWF farther to
the west with the feature than the GFS. Both want to spit out a
little light precipitation with the system, though consensus would
leave us mainly dry with the divergence in the solutions.

Not much change in the pattern through the end of the week with
temperatures remaining above normal through the period. Cannot rule
out periodic chances of very light snow/flurries with various
impulses tracking across the region, but timing/placement is varying
among models, so hard to pin down when/where this could occur.
Models are beginning to hint at a possible change in the pattern by
next weekend as the upper level flow transitions to a more
zonal/progressive pattern across the CONUS.


.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
Issued at 506 AM CST Sun Dec 10 2017

VFR conditions through the period. Some MVFR ceilings may creep to
around the the Buffalo Ridge from central SD, but should not drop
farther southwest. Very late in the period MVFR ceilings should
start to approach from the north and may reach KHON shortly before
12z Monday.




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