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Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota
522 PM MDT Thursday Oct 8 2015

Short term...this evening through Friday night
issued at 236 PM MDT Thursday Oct 8 2015

Upper wave is now crossing the County Warning Area within the northern branch of the jet.
Showers are ending from northwest to southeast across western South Dakota...with the northern to
central Black Hills just now drying out. Some lingering showers still
affecting Butte County to Colony...but these are more diurnal
based and will dissipate quickly with the setting sun. Skies will
continue to clear tonight from north to south as high pressure
builds in. Temperatures are expected to drop into the low to middle
40s...with even some upper 30s across central South Dakota where better
radiational cooling will exist overnight before a light return
flow sets up toward sunrise. Low amplitude upper ridging will set up
across the northern rockies Friday. Warm air advection will bring a warming
trend tomorrow into the extended. Highs will reach the middle 60s to
middle 70s Friday. Other than some passing clouds...dry weather and
sunshine are expected Friday with clearing skies for Friday night.

Long term...Saturday through Thursday
issued at 236 PM MDT Thursday Oct 8 2015

A broad upper level ridge will peak over the forecast area on
Saturday as the thermal ridge amplifies. This will lead to dry
weather with high temperatures ranging from 10 to 20 degrees
warmer than average. The upper ridge will shift off to the east on
Sunday as a shortwave trough crosses the Canadian prairie
provinces and swings into the northern plains. At the surface...a
fast moving cold front will cross the forecast area Sunday
aft/eve. 45-50kt 85omb winds are forecast behind the cold front by
the latest 12z run of the GFS. Cold air advection and subsidence behind the front
will aid ll mixing and momentum Transfer so expect very windy
conditions over much of the forecast area on Sunday aftn/eve.
Expect dry weather with the frontal passage due to a lack of low
and middle level moisture. The first half of next week will feature
west/northwest flow aloft...a series of dry/weak shortwaves and
slightly warmer than average temperatures.


Aviation...(for the 00z tafs through 00z Friday evening)
issued at 520 PM MDT Thursday Oct 8 2015

5000-8000ft above ground level ceilings will persist across northeast Wyoming and
southwest/south central South Dakota this evening...with skies
becoming clear overnight. VFR conditions for Friday.


Unr watches/warnings/advisories...
South Dakota...none.


Short term...13
long term...10

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