Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 161742 AAB

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1142 AM CST Fri Feb 16 2018

Issued at 1139 AM CST Fri Feb 16 2018

No changes planned to the today period forecast. Going forecast of
mostly sunshine and temps warming into the 20s and 30s still looks
on track.

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


.SHORT TERM...(Today through Saturday Afternoon)
Issued at 322 AM CST Fri Feb 16 2018

Precipitation chances Saturday morning will be the main forecast
issue in the short term.

The region is currently under the influence of a surface high
pressure. With clear skies and light winds, temperatures are ranging
in the single digits on either side of zero. The surface high will
move into southwest Iowa today allowing for southwesterly winds over
the region. These winds will bring warmer temperatures with highs
reaching the mid 20s, to the lower 30s. Winds will be gusty in
eastern South Dakota where patchy blowing snow could be possible.
Did not mention blowing snow as the strongest winds should occur
where there is little snow cover.

A weak system will cross the region tonight with mostly cloudy skies
and westerly winds expected. With the cloudy skies, temperatures
will remain mild with lows in the teens. A stronger system, along
with a broad upper level trough will cross the region on Saturday.
Models continue to advertise light snow with this system with
accumulating snow possible in central SD, including the Pierre area.
Snowfall amounts of a half inch to one inch could be possible. The
6Z NAM is further north with the snow Saturday morning with KMBG and
KABR seeing higher snowfall amounts. The 6Z shows one to two inches
of snow.

.LONG TERM...(Saturday Evening through Thursday)
Issued at 322 AM CST Fri Feb 16 2018

It appears the long wave pattern over the conus will take on a
different look during the long term. Energy digging along the west
coast/western conus will bring a southwest flow to the region, thus
spelling increases chances for pcpn. The first round will be
Saturday night and Sunday. Nearly all 00Z models except GFS have
trended north with sfc low track, and consequent baroclinic zone.
Partial thickness progs, as well as top down grids suggest perhaps
some fzdz in the pcpn mix so have included that. Pcpn amounts
overall look fairly light. A more active baroclinic zone sets up
Sunday night through Monday night from southwest to northeast across
the state as short wave energy moves across the region underneath a
125 knot jet stream. The models are in fair agreement for the Sunday
night to Monday night time period, leading to fair confidence. As
for temperatures, they`ll start the period near normal, but should
then take a tumble for Monday and Tuesday as cold air slides in from
the northwest. The cold temperatures will lead to high snow ratios
for Monday through Tuesday. Temperatures should then rebound after
Tuesday as the airmass across the region modifies.


.AVIATION...(For the 18Z TAFS through 18Z Saturday Afternoon)
Issued at 1139 AM CST Fri Feb 16 2018

There is a chance for some sub-VFR weather conditions Saturday
while a quick-moving area of low pressure brings some light snow
potential across the forecast area. Until then, good VFR is
anticipated for all four terminals.




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