Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 182038

Area Forecast Discussion
National Weather Service Aberdeen SD
338 PM CDT Sat Mar 18 2017

.SHORT TERM...(This Evening through Monday Night)
Issued at 338 PM CDT Sat Mar 18 2017

With sunny skies and warm advection, a few locations in central
South Dakota have approached Red Flag, as a sliver of dry mid level
air mixes down across the southern half of the Missouri valley.
Slightly more humid air (dewpoints in the upper 20s vs. teens) is
moving out of Nebraska into the CWA. Most of the area remains cool
as warm advection tops a still relatively stable atmosphere thanks
to the southeast component. Thus, will continue to pass on any fire
weather headlines for the remainder of the day.

The core of 1/2km winds moves east overnight into the James valley
and Coteau region. With a south/southwest component and a core of
50kts according to the GFS, along with pressure falls around 4-6mb,
some of the gustiness will translate to the surface. Not the most
favorable direction for downslope conditions, peak winds on the
ridge could still top 40mph overnight. This core of strongest winds
moves into Minnesota by morning. To the west we will also see a weak
front move through. While we will see a favorable direction for
mixing, and some drier air aloft, there is little thermal difference
across this feature. The aid in mixing will help us warm into the
60s/70s. Winds through almost 700mb are less than 20kts so not much
wind on the backside of this front. Thus, while RH% will fall to 20%
or lower, winds will be below Red Flag thresholds. NAM profiles do
suggest some post frontal mid clouds by the afternoon across north
central counties, probably too late to influence the temperature

We will see an upper trough move across Canada for the start of next
week. Southwest to westerly flow and a 120kt jet across the northern
tier CONUS will support a few weak waves. These will ride over high
pressure nosing out of Canada however, so no great opportunities for
moisture through late Monday. Temperatures will be much closer to
average though.

.LONG TERM...(Tuesday through Saturday)
Issued at 338 PM CDT Sat Mar 18 2017

Will still be watching an area of precipitation over southwest and
south central SD Tuesday morning, mainly in the form of snow. It
appears precip will be fighting with a dry ridge of high pressure
over the eastern Dakotas, so wonder if the northern fringe of POPs
may have to be cut back over the next few forecast cycles and
confine things more to the southwest CWA. Will continue to watch
trends. Otherwise, larger storm system moves out in the the
Plains by late week, with differences continuing to be noted
amongst the models in regards to evolution and timing. There is
also much disagreement to be had still with a lead shortwave that
moves across the region on Wednesday. The 12Z EC has come in a bit
stronger with this feature now and brings a decent amount of
precip across the CWA during the day Wednesday. Precip may start
off as snow, but thermal profiles suggest things turning to rain
during the course of the day. For the system later in the week, it
appears models are trying to indicate southeast SD with the
highest chances for precip, but still much time for things to
change. Did not stray too far from SuperBlend guidance for POPs.


.AVIATION...(For the 18Z TAFS through 18Z Sunday Afternoon)
Issued at 1226 PM CDT Sat Mar 18 2017

Conditions will remain VFR through the TAF forecast period,
although the main concern will be wind shear overnight. A strong
low level jet will develop during the overnight hours, creating
low level wind shear conditions. Have inserted mention of this
into the TAFs.




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