Area Forecast Discussion
Issued by NWS Aberdeen, SD

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743
FXUS63 KABR 222130
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
330 PM CST Wed Feb 22 2017

.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
consistency.

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 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1127 AM CST Wed Feb 22 2017

VFR conditions during the early afternoon hours will give way to
an area of MVFR cigs overspreading the region later this afternoon
and this evening. Also, look for an area of snow to approach the
southwestern CWA Thursday morning, with MVFR vsbys possible,
including at KPIR.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Warning from 9 AM Thursday to 6 PM CST Friday for
     SDZ045-048-051.

     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.

MN...None.
&&

$$

SHORT TERM...TMT
LONG TERM...Parkin
AVIATION...Parkin



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