Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 211743 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1243 PM CDT Mon Aug 21 2017

Issued at 1243 PM CDT Mon Aug 21 2017

18z aviation discussion updated below.

UPDATE Issued at 1158 AM CDT Mon Aug 21 2017

Showers and storms will continue to move east and out of the
region into the early afternoon. The clouds will also only slowly
decrease into the afternoon hours from northwest to southeast.
Updated forecast.


.SHORT TERM...(Today through Wednesday Afternoon)
Issued at 400 AM CDT Mon Aug 21 2017

A rather large complex of showers and thunderstorms has been ongoing
for several hours across northwest and now into central/north
central SD. Mid level impulse moving across the region is responsible
for this. Hi-res models are just now catching onto this feature,
while several hours ago they were all performing rather poorly.
Still not too confident on the evolution of all this, but it appears
this activity will move into the James valley in the next few hours
before gradually diminishing in coverage as it moves further east.
There could be some additional development across the area as well,
but indications point to this being the main show for the time
being. That said, all the cloud cover associated with this complex
could prevent viewing of the eclipse, but mainly for eastern areas
of the CWA. Central SD into the James River valley appears to be in
a decent opportunity for viewing as the back edge of the cloud cover
moves across the region later this morning.

Surface high pressure will build south into the area overnight,
bringing mostly clear skies and dry conditions. This high will
remain in place on Tuesday with tranquil conditions and pleasant
temperatures. In fact, the high will still have an influence over
the area on Wednesday and it appears dry conditions will continue
through mid-week.

.LONG TERM...(Wednesday Evening through Sunday)
Issued at 400 AM CDT Mon Aug 21 2017

Not much change overall to the extended which will feature a
meridional pattern, starting with a high amplitude upper ridge
moving into the central CONUS. An upper trough will move into
northwest Canada, resulting in zonal flow for the weekend, with an
upper ridge building back across the western CONUS for the start of
next week. Generally this will result in dry conditions with only a
short period where we will see any shortwave activity or mid level
moisture - Friday and Saturday. As for temperatures, we start with a
broad expanse of high pressure to the southeast and northeast
initially, with a lee low across western Nebraska. Low level flow
will be east to southeast for the latter half of the work week, so
Thursday will feature average temperatures. The flow becomes more
southerly ahead of the upper pattern transition, leading to
temperatures a touch above average for Friday. A quick frontal
passage will bring our numbers back closer to average for the


.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
Issued at 1243 PM CDT Mon Aug 21 2017

VFR conditions are expected through today and tonight at all




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