Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 252327 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
627 PM CDT Fri May 25 2018

Issued at 625 PM CDT Fri May 25 2018

See updated aviation discussion below.


.SHORT TERM...(This Evening through Saturday)
Issued at 210 PM CDT Fri May 25 2018

In west to northwest flow aloft part of our CWA, where
temperatures are pushing 90, and dewpoints are in the 40s and 50s,
we have already developed scattered convective cells, which
matches the previous forecasters thinking and is backed up by
several CAM solutions. Given this is primarily diabatically
driven, most convection will dissipate by late afternoon/early
evening. That leaves us with weak westerly flow, dry air and
favorable radiational conditions overnight. Most guidance drops
temperatures into the upper 50s and low 60s, so will run with that
(along with taking the normal liberties with the James valley
cold air sink).

A 500mb ridge builds overhead for Saturday. There will also be a
surface ridge axis moving overhead during the day, with low level
westerly flow and good mixing, transitioning to southerly flow with
an increasing gradient. Dewpoints again will crash into the 50s with
temps into the 90s.

.LONG TERM...(Saturday Night through Friday)
Issued at 210 PM CDT Fri May 25 2018

The long term will feature a couple active periods during the time
frame. Initially, ridging aloft is expected to keep the region
mainly dry, especially the eastern CWA through most of the holiday
weekend.  The exceptions being Saturday night and again Monday
night. Increasing LLJ/elevated instability could serve to kick off a
few thunderstorms Saturday night. For Monday night and Tuesday, upper
trof over the western CONUS is expected to shear out across the
plains, likely in pieces. The GFS is the strongest of the
solutions, and likely the outlier, but at least the other models
show a similar evolution of the trof ejection, just a weaker
solution. After that trof moves through there`ll likely be a lull
in activity as mid level ridge builds again across the western
high plains.

Temperatures throughout the period should favor above normal,
especially daytime highs.


.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 625 PM CDT Fri May 25 2018

VFR conditions will prevail across the area tonight and through
the daytime hours on Saturday.




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