Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 150438

Area Forecast Discussion
National Weather Service Sioux Falls SD
1038 PM CST Thu Dec 14 2017

.SHORT TERM...(This evening through Friday)
Issued at 332 PM CST Thu Dec 14 2017

An upper level shortwave trough is moving through the region today,
providing enough lift for widespread cloud cover and scattered
rain/snow showers. Given the modest lift and dearth of moisture to
work with, any showers should remain light, with less than half inch
accumulations through the day. Most places will only receive a
dusting to a couple tenths of an inch. North and east of the James
River valley, an hour or two of freezing drizzle is possible as snow
showers end, but very little accumulation is expected on roadways as
clouds quickly erode and drier air moves in. Nevertheless, be
cautious traveling over bridges and watch for slick spots elsewhere.
Locations south and west of the James River will be warm enough this
afternoon to see rain or rain mixed with snow. Only minor impacts
are expected with this system. Precipitation should exit the region
a few hours after sunset, roughly after 9pm CT.

Friday will bring a change to southwest winds and temperatures about
5 to 10 degrees warmer than Thursday. The ridge to our West makes
an eastward push and surface high pressure strengthens to our
south. These winds will be breezy, but nothing out of the
ordinary, with gusts in the 20 mph range.

.LONG TERM...(Friday night through Thursday)
Issued at 332 PM CST Thu Dec 14 2017

The weekend will bring a return to light north and northwest winds.
Relatively mild temperatures to our north keep the area above
seasonal normals, with highs in the mid 30s to low 40s for most. A
weak pressure trough moves through Sunday night into Monday, but
again the forecast remains mostly dry with weak forcing and lack of
moisture. Temperatures stay about 10 degrees above seasonal normals
through Tuesday. Breezy northwest winds develop Tuesday afternoon as
a weak cold front pushes southward.

The most interesting part of the forecast is middle of next week
onward. There is potential for a more widespread precipitation
event, and a change to cooler temperatures by the end of the work
week. The pattern looks to change with a longwave trough setting up
over the western CONUS. The change to colder temperatures is shown
in several long range models, so this is moderate confidence at this
point. However, there are vast differences in how each model handles
timing and strength of the shortwave energy, so there is very low
confidence in where and when snow could fall. This part of the
forecast will continue to be closely monitored, given the ramp up in
Christmas travel by the end of next week.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1035 PM CST Thu Dec 14 2017

Low end VFR stratus will linger through the overnight hours.
Patchy MVFR ceilings are expected to redevelop mainly across east
central SD into southwest MN and portions of northwest IA in the
early morning hours. FSD is expected be on the edge of the this
lower stratus, however HON and SUX should remain VFR overnight.
By mid to late morning, the low stratus will lift, with mid and
high clouds/VFR conditions remaining.




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