Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 061241 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
641 AM CST Tue Dec 6 2016

.UPDATE...
Issued at 635 AM CST Tue Dec 6 2016

See below for an aviation forecast discussion for the 12Z TAFs.

&&

.SHORT TERM...(Today through Thursday Afternoon)
Issued at 439 AM CST Tue Dec 6 2016

Winter storm continues to evolve across the Northern Plains and have
made some changes to hazards today based on latest thinking and
current/short term trends. Biggest impacts still expected across ND,
but will still see strong winds and areas of light snow and blowing
snow over the CWA today.

First, the winds. Have seen very strong winds in the Coteau region
through the night into early this morning with winds gusting over 70
mph at times at the Peever RWIS. Several other sites solidly in wind
advisory criteria. Will see strong and gusty winds through the day
today, likely reaching advisory criteria at times. Have therefore
issued a Wind Advisory for areas least affected by snow and blowing
snow.

Areas across northern SD into west central MN where the combination
of light snow and blowing snow will create reduced visibility, have
issued a Winter Weather Advisory. Radar imagery over the past
several hours has shown the massive area of light snow over ND
slowly drifting southward into northern SD. KMBG visibility has come
down once again with sites just over the border in ND down to around
1/4 SM. Hi-res models show light to moderate snow wrapping down into
northern/northeast SD and into west central MN through the day.
Longer duration snowfall, thus higher totals, are expected across
the Coteau region of northeast SD where up to 2 inches are possible.
With the strongest winds expected here today, could be looking at
some rather nasty conditions with the blowing snow, should the snow
rates become enough to create low visibility.

The rest of the short term is cold and windy after this storm system
moves out. Wind chills will be below zero with highs only in the
single digits and teens, with overnight lows in the single digits.
Another lobe of energy rotates around the upper low on Wednesday,
thus bringing a chance for some snow showers to eastern parts of the
CWA during said time frame.

.LONG TERM...(Thursday Evening through Monday)
Issued at 439 AM CST Tue Dec 6 2016

Compared to 24 hours ago, the Canadian, GFS and ECMWF 00Z
deterministic runs showed some better agreement and coverage of
precipitation regarding the Saturday system. While the flow pattern
is quasi-zonal from appx mid-way through the extended forecast
period right on through appx day 12, the agreement that the 00Z GFS
and ECMWF showed in system timing/precip placement is uncanny. While
the polar front is hanging out over the region in this fairly flat
upper level flow pattern at the end of the week and beyond, there
appears to be no lack of low to mid-level thermal gradient for
transient systems to tap into for frontogenetic-forcing purposes.
Expect precipitation chances to continue roughly every 24 to 48
hours from Saturday through several days beyond the 7-day forecast
period. Also, while it hasn`t started to register yet on the
Ensembles Situational Awareness Table, there still appears to be
some potential (two mornings in a row) for 925hpa air as cold as or
colder than -25C to advect down into the region by the middle of
next week. Maybe, by the middle of December, air that cold isn`t
that far from climo normal? Either way, it could be colder this time
next week than it is right now for the middle of this week. Stay
tuned.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 635 AM CST Tue Dec 6 2016

Strong west to northwest winds will continue through the day today
into tonight. Gusts in excess of 45 mph are likely across much of
the area. MVFR to VFR Cigs will gradually improve to prevailing
VFR by early this afternoon, while IFR to MVFR visbies in falling
and blowing snow will also gradually improve but will be tied
moreso to whenever the falling snow ends, which should be sooner
than later at KPIR/KMBG but could be persisting into the late
afternoon hours today for KABR/KATY.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 6 PM CST /5 PM MST/ this evening
     for SDZ003>011-015-016-021.

     Wind Advisory until 6 PM CST /5 PM MST/ this evening for
     SDZ017>020-022-023-033>037-045-048-051.

MN...Winter Weather Advisory until 6 PM CST this evening for MNZ039-
     046.

&&

$$

UPDATE...Dorn
SHORT TERM...TMT
LONG TERM...Dorn
AVIATION...Dorn



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