Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 262009

Area Forecast Discussion
National Weather Service Aberdeen SD
309 PM CDT Tue Sep 26 2017

.SHORT TERM...(This Evening through Wednesday)
Issued at 306 PM CDT Tue Sep 26 2017

Upper low currently over North Dakota will continue to move
northeast, and away from the region tonight. Behind the system the
clouds will continue to break up. However, without much additional
dry advection, and moist soils across the cwa, am anticipating
sct/areas of fog tonight.  Fog may be more prominent over the east
where heavier amounts of rain fell in the last few days.  Hi-res
models have targeted James and Big Sioux valleys, as well as coteau
for more widespread fog.  Other issue overnight is frost potential.
With wet ground in place and fog likely to form, temperatures will
probably hold above freezing, but can`t entirely rule out patchy
frost and will include in grids.

Additional sunshine on Wednesday should allow for warming
temperatures, especially since airmass will begin modification via
warm air advection aloft, and westerly breezes in the boundary

.LONG TERM...(Wednesday Night through Tuesday)
Issued at 306 PM CDT Tue Sep 26 2017

Fairly good agreement on long term trends. A weak pressure pattern
will be in place initially with a cool airmass overhead. High
pressure noses out of Canada Friday behind a backdoor front with a
little re-enforcing shot of cool air. As this high passes east, we
see a cut of low begin to lift northwards, deepening as it moves out
of the intermountain west, and becoming a negatively tilted trough.
Then a second wave moving across the northern tier CONUS will push
into our area for the start of next week. The main result will be a
strong pressure gradient across the area Saturday as a lee low forms
in Montana. A 14mb pressure gradient along with pressure falls of 3
to 5 millibars means we will see strong southerly winds Saturday. A
low level jet develops Saturday night and will mix out across the
east early Sunday before a cold front moves across the area. As for
precipitation chances, there are several waves of mid level
isentropic ascent, with a timing of Sunday into early Monday,
otherwise the forecast looks dry.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 653 AM CDT Tue Sep 26 2017

VFR conditions are expected through most of the night. However,
fog is possible late and that may affect vsbys, especially at




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