Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 080528 AAD

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1128 PM CST Wed Dec 7 2016

Issued at 1123 PM CST Wed Dec 7 2016

See updated aviation discussion below.

UPDATE Issued at 1103 PM CST Wed Dec 7 2016

Continue to see widespread light snow and blowing snow across the
eastern half of the CWA. With much more activity coming upstream,
have increased POPs to likely/categorical through Thursday
morning. Previous forecast seemed to wind things down too quickly.
Also beefed up blowing snow mention, which is rather prevalent
across the region as winds are staying up and the fact that the
snow is so light and fluffy in nature. Do not expect serious VSBY
reductions, as snowfall rates will remain rather light with
minimal accums.


.SHORT TERM...(This Evening through Thursday Afternoon)
Issued at 243 PM CST Wed Dec 7 2016

Have continued high POPs for light snow falling mainly east of
ABR. A ridge of cold Arctic high pressure will nose across far
western SD overnight. The result will be winds diminishing to
mainly less than 15kts, and temperatures falling into the 0 to
-10F range by daybreak Thursday. Coupled with the winds, wind
chill values will be getting close to -25 to 30F. A Wind Chill
Advisory has been posted for Corson, Dewey, Walworth, Edmunds,
Potter, and Faulk Counties, mainly overnight into mid morning
Thursday. Elsewhere, wind chill values will at least temporarily
fall into the -15 to -23F range Thursday morning.

The main benefit to the sfc ridge building in will be a diminishing
trend to the strong winds of late. While northwest winds will remain
for the day Thursday, 10-20kts will be common. Kept temps a couple
degrees higher than guidance over the mainly snow-free locations
over our south central locations.

.LONG TERM...(Thursday Evening through Wednesday)
Issued at 243 PM CST Wed Dec 7 2016

The main forecast issue in the long term will be first snow this
weekend, and then temperatures later on. The system that enters the
picture for late Friday night and Saturday is being handled somewhat
differently by the main models. The CMC/GFS maintain a pretty good
brush with snow on especially Saturday. A decent looking H3 jet is
expected to provide UVM per right entrance region moving over the
CWA during the day. This is apparent in omega/frontogenesis progs.
Meanwhile, the ECMWF`s jet structure looks a bit different and
slows up the process a bit, and pushes its surface features
further south vs the other two models. At this point hard to pick
a winner, but will have to maintain due diligence until models
pull into line with each other.

Another big difference is the predicted cold push around 144+ hours.
The ECMWF remains much more bullish with this vs the GFS/CMC. The
CMC/GFS indicate more of a glancing blow of cold air, where as the
ECMWF ushers in -25C or colder H85 air to most of the region. With
the models maintaining consistency to their respective
prognostications from the 00Z run, it`s hard again to determine the
correct answer. Some of the GEFS plumes do support the ECMWF so the
Euro model may be on to something.  Temperatures overall should be
below to much below normal for the entire forecast.


.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1123 PM CST Wed Dec 7 2016

Light snow will continue across much of the eastern and central
CWA through the overnight hours, and combined with gusty northwest
winds, will create occasional periods of MVFR vsbys. MVFR cigs
will remain across the east as well, with cigs bouncing between
MVFR and VFR across the west. The winds will diminish some during
the day Thursday, along with the precipitation coming to an end.


SD...Wind Chill Advisory until noon CST /11 AM MST/ Thursday for



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