Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 230000 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
600 PM CST Wed Feb 22 2017

Issued at 538 PM CST Wed Feb 22 2017

See below for an aviation forecast discussion for the 00Z TAFs.


.SHORT TERM...(This Evening through Friday Night)
Issued at 329 PM CST Wed Feb 22 2017

Models still continue to suggest the storm system affecting the area
Thursday and Friday will mainly hit southern SD the hardest. In
fact, the 12Z runs of the EC/GFS/Canadian have all nudged southward
a bit more. The NAM remains the big outlier with it`s northern
solution, but even the 18Z run of the NAM trended south a bit. There
were some big adjustments downward to QPF as the NAM contaminated
the blends with it`s northward track and high amounts of QPF.
Determining headlines was the biggest challenge today, since there
is a rather sharp gradient in snow totals, and a continued threat of
a shift in track. Based on latest forecast snow accums, decided to
upgrade the I-90 counties to a Winter Storm Warning. Also chopped
off the northern part of the Winter Storm Watch, and could have
chopped off even more. Although, was a bit concerned about the
strength of the winds causing issues even if the 6 inches are not
met. Imagine at some point a Winter Weather Advisory buffering any
warnings, to highlight less snow accums and impacts north of the
main heavy snow accumulating area.

.LONG TERM...(Saturday through Wednesday)
Issued at 329 PM CST Wed Feb 22 2017

The first half of the extended period looks to be dry, with high
pressure in control for much of that time. Main concern turns to the
early part of next week. Previous model runs had a storm system
forecast to track across the region Monday night into early
Wednesday. Current runs have this system tracking much further
south, with little impact on the CWA. Am a bit leery about this
sudden change, so will continue to keep slight chance to chance pops
in for a snow or rain/snow mix until there is more run to run model

Near to above normal temperatures are expected through the period,
with daytime highs mainly in the 30s and overnight lows in the teens
to lower 20s.


.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 538 PM CST Wed Feb 22 2017

KPIR is about to be over-run by low (sub-VFR) clouds, joining the
other three terminals under this blanket of cold air stratus.
Expect cigs to fluctuate between appx 800ft agl and 2500ft agl
over the next 24 hours. Regional radars indicate that a few
pockets of light returns (flurries mainly) persist, so it`s
possible some folks could see a flurry or two over the next few
hours. Also, look for an area of snow to approach the
southwestern CWA Thursday morning, impacting KPIR initially,
before spreading over toward the KATY terminal late in the day.


SD...Winter Storm Warning from 9 AM Thursday to 6 PM CST Friday for

     Winter Storm Watch from Thursday evening through Friday
     afternoon for SDZ018>023.

     Winter Storm Watch from Thursday morning through Friday morning
     for SDZ033-035>037.



LONG TERM...Parkin
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