Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 151942

Area Forecast Discussion
National Weather Service Aberdeen SD
242 PM CDT Thu Mar 15 2018

.SHORT TERM...(This Evening through Friday)
Issued at 241 PM CDT Thu Mar 15 2018

Fairly good confidence now with the system. Despite initially seeing
clouds move in tonight, a northeast low level fetch will result in a
sub-freezing nocturnal boundary layer. This will also be a dry layer
with the classic low dewpoint trace in the boundary layer evident in
BUFKIT. In the far south central, we can also see in BUFKIT, milder
air overtop this layer. As the system saturates, this may result in
enough energy to melt snow, so initially we may see some freezing
rain/sleet, but profiles quickly cool thanks to strong lift. Thus, a
quick change over to heavy wet snow. SREF probability for an inch
QPF in 24 hours is 30 percent for southern counties, though ratios
of 10:1 or less seem appropriate. Thus, with latest QPF/Snow ratios -
expanded area Winter Storm warning into the Pierre area, but north
and east is less certain. Peak lift evolves rapidly to the east and
weakens, so a quick drop in intensity can be anticipated, but that
also comes with a loss of ice in the dendritic growth zone. There
still remains evident in BUFKIT a thick stratus layer, so retained
some light QPF ice in freezing drizzle late Friday into early

.LONG TERM...(Friday Night through Thursday)
Issued at 241 PM CDT Thu Mar 15 2018

The extended period begins with high pressure over the central part
of the country on Saturday. The high will get pushed east on Sunday
as low pressure intensifies over eastern Colorado, then pushes east
across the Kansas/Oklahoma region. An inverted trough associated
with the low will extend as far north as North Dakota, and looks to
become the focus for precipitation Sunday though Tuesday morning.
Precipitation type will be dependent on temperatures, with warm
enough conditions expected on Sunday and Monday during the day for
the precipitation to be rain at times. Overall snowfall amounts will
not be much, with an inch or two possible during the 48 hour time

High pressure moves back in Tuesday night through the day Wednesday.
Models then diverge quite a bit at the end of the period, with the
ECMWF and the Canadian keeping conditions dry, while the GFS begins
to bring another system over the area later in the day Thursday.
Will stick with mainly dry for now, and introduce small pops into
the Thursday night period.

Temperatures will be fairly mild through the period, with highs in
the 30s and 40s. Monday and Tuesday will be the coolest days due to
the precipitation, with highs in the lower to mid 30s.


.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1230 PM CDT Thu Mar 15 2018

VFR conditions will become IFR for KPIR Friday with a system
moving in that will generate heavy snow. Much less certain where
the categories will lay, between IFR/MVFR potentially for KATY
close to the end of the TAF period.


SD...Winter Storm Warning from 4 AM CDT /3 AM MDT/ to 7 PM CDT /6 PM
     MDT/ Friday for SDZ033-035-045-048.

     Winter Weather Advisory from 7 AM Friday to 1 AM CDT Saturday
     for SDZ036-037-051.

     Winter Weather Advisory from 7 AM to 7 PM CDT Friday for SDZ034.



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