Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 291825 AAC

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1225 PM CST Tue Nov 29 2016

Issued at 1221 PM CST Tue Nov 29 2016

See below for an aviation forecast discussion for the 18Z TAFs.

UPDATE Issued at 1041 AM CST Tue Nov 29 2016

Added Lyman/Buffalo to the Winter Weather Advisory this morning
and nudged winds/gusts up a few knots to better match obs across
the Missouri River valley and west river. WSW is now strongly
worded for near blizzard conditions at times today/tonight
especially throughout the Missouri River valley where reports of
occasional visby reductions to a quarter mile or less is occurring
when it`s snowing combined with the strong wind. Outside of these
snowbands rotating through from the north, visibility is higher
than one quarter mile. Temperatures are borderline (still
marginally too warm at 28 to 32 degrees) across the Missouri River
valley and west river for creating the kind of surface conditions
where significant lofting (blowing) of snow on the ground can
occur. So, maintaining areas of blowing snow mention across
central/north central South Dakota for those times when strong
winds and falling snow can aide in some nuisance blowing/drifting
snow as well. Updates are out.

UPDATE Issued at 523 AM CST Tue Nov 29 2016

See updated aviation discussion below.


.SHORT TERM...(Today through Thursday Afternoon)
Issued at 353 AM CST Tue Nov 29 2016

Upper trough and associated TROWAL moisture continues to persist
across the forecast area this morning with a broad area of generally
light snow and strong winds, the corridor of which is strongest over
the Missouri valley and points west. Conditions will change little
over the course of the day as the low wobbles over western
Minnesota, aside from the fact that upstream returns are a bit
higher and high res guidance suggests some of these stronger areas
of snow will migrate into the CWA.

Accumulations have been light overnight at the office,
though its difficult to tell at this point how the rest of the CWA
has faired. The only other samples taken are downtown KELO
webcams from Eureka/Miller/Watertown, all indicating either snow
or ice and generally poor driving conditions. As such, have
expanded the winter weather advisory to the east/south and
extended in time to match surrounding offices. This fits the
narrative as bands of snow and reduced visibility due to strong
winds will likely fill in the James valley and upslope areas of
the Coteau through the day.

As the system continues to weaken, NAM bufkit profiles suggest we
lose temperatures in the dendritic growth zone over the Sisseton
hills, and thus could see snow change to freezing drizzle. At the
same time, omega values drop off so there is still uncertainty as to
whether this will materialize or not.

.LONG TERM...(Thursday Evening through Monday)
Issued at 353 AM CST Tue Nov 29 2016

The extended period looks to be mainly dry, with just a couple
periods of light snow possible over the weekend as high pressure
exits the region and a low pressure system tracks through. Limited
moisture and upper level support should lead to just some brief
periods of light snow Saturday afternoon into the day Sunday, mainly
across the north and east, with no accumulations expected.
High pressure begins to nose back over the region from the northwest
early next week.

High temperatures will be right around normal through the period,
mainly in the upper 20s to mid 30s, with overnight lows in the upper
teens to mid 20s.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday Afternoon)
Issued at 1221 PM CST Tue Nov 29 2016

A low pressure system will continue to bring a mix of
precipitation types to KABR and KATY today before p-type changes
back over to all snow for tonight. P-type will remain snow today
and tonight at KPIR and KMBG. Cigs/visbys will jump back and forth
between IFR and MVFR as occasional bands of snow work southward
through the region at all four terminals. Areas of blowing snow
will also coincide with the falling snow especially at KPIR and
KMBG where 25 to 35 knot winds with higher gusts continue today
and tonight.


SD...Winter Weather Advisory until 6 AM CST /5 AM MST/ Wednesday for



SHORT TERM...Connelly
LONG TERM...Parkin
AVIATION...Dorn is the U.S. government's official web portal to all federal, state and local government web resources and services.