Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 170836

Area Forecast Discussion
National Weather Service Aberdeen SD
336 AM CDT Thu Aug 17 2017

.SHORT TERM...(Today through Saturday Afternoon)
Issued at 335 AM CDT Thu Aug 17 2017

Rain is slowly exiting the CWA with just the western fringe still
affecting Big Stone and Traverse counties. Cloud shield continues to
advance eastward as well, although a stubborn low cloud deck is
being revealed as nearly stationary over the Coteau - underneath the
departing mid clouds. Will continue to monitor for fog potential,
but with still a bit of a breeze, it may be tough. A few hours ago,
many of the hi-res models were showing lowered VSBY in the Coteau,
so ran with this and inserted some patchy/areas of fog mention in
the grids. Perhaps they were picking up on moist upslope flow into
the Coteau - seemed reasonable so added fog mention. Although the
past couple runs of a few of the hi-res models have backed off a bit
on fog. Nonetheless, still have some mention of it in the forecast
through early morning. May have to keep an eye on central SD, where
hi-res models were not showing anything, but where it actually makes
more sense. Because here, winds are actually light under the ridge
axis and low levels are still moist. KMBG has recently dropped to

For later today, expect the clouds across the east will have pushed
off and it appears to be a mostly sunny day across much of the area
with warmer temps ranging from the upper 70s to the upper 80s. A
nice warm-up after the cooler readings of past days. Will be
watching upper level shortwave energy moving into the western
Dakotas this afternoon. Hi-res CAM solutions show scattered showers
and storms moving into the western CWA by late afternoon or close to
00Z this evening. Instability is minimal but there is a bit of shear
to work with. Expect scattered activity to move eastward across the
CWA through the overnight hours as the shortwave continues moving
east. Lingering shortwave energy will drop southeast across eastern
portions of the CWA on Friday, with continued chances for showers
and thunderstorms.

Conditions dry out Friday night and Saturday with a warm/hot air
mass moving into the region. It`s been a while since this warm of an
air mass has moved into the area as 850 mb temps look to rise into
the +20s Celsius by 00Z Sunday. With favorable south to southwest
mixing winds, temps look to warm quite nicely into the 80s and 90s.
Stayed fairly conservative with highs on Saturday - sticking close
to SuperBlend where otherwise this synoptic pattern might suggest
going higher. All the recent rain and wet soils across the area may
hold temps at bay and prevent highs from overshooting guidance like
we see in extended dry patterns.

.LONG TERM...(Saturday Evening through Wednesday)
Issued at 335 AM CDT Thu Aug 17 2017

The upper pattern will evolve over the course of the long term from
mostly zonal flow with an upper trough across western Canada and a
second trough across the eastern CONUS - to a slight trough across
the central CONUS early next week - followed by increasing ridging
in the western CONUS for the second half of the work week. A surge
of hot air at the end of the short term will bleed over into
overnight temperatures to start the extended, with the front across
the area and south/southwest low level flow across the eastern half
of the state. The front will stall over the region, with high
pressure to the north. Low level flow shifts to easterly Sunday, and
a weak wave in zonal flow will allow for the development of a lee
low on the tail end of this feature late Sunday. We see favorable
placement of a low level jet Monday AM, along with the right
entrance region of a jet streak in North Dakota. Guidance blend pops
at 40-60 percent is fine for a day3/4 warm front elevated convection
event. Due to zonal flow aloft, this will also be a short lived
episode of precipitation with mainly dry conditions thereafter.

Temperatures for the upcoming week will be defined by cooler air
dislodged out of Canada into the eastern half of the CONUS, and
hotter air building out west, and the CWA in between.


.AVIATION...(For the 06Z TAFS through 06Z Thursday Night)
Issued at 1215 AM CDT Thu Aug 17 2017

Rain should be tapering off at KATY over the next hour or two. But,
sub-VFR conditions are expected to persist at KATY into Thursday
morning before conditions begin to improve. KPIR/KMBG/KABR should
remain VFR over the next 24 hours, although these three terminals
will be mostly clear for the rest of the night on decreasing winds.
The potential for some patchy to scattered coverage of MVFR/IFR fog
is beginning to increase a bit.




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