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Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota
515 PM MST Thursday Nov 27 2014

Short term...this evening through Friday night
issued at 206 PM MST Thursday Nov 27 2014

21z surface analysis had low over north central Montana with warm
front into western NE. Water vapor loop had upper ridge over The
Rockies...heading east. Warm front will continue moving east
exiting the County Warning Area overnight. Temperatures tonight will be tricky
with amount of mixing having a large effect on lows...tended above
guidance in the west where higher winds expected...and slightly
below in the east.

Friday...much warmer air behind front with potential temperatures
in the upper 50s as upper ridge shifts into the northern plains
and downslope flow brings very nice weather.

Friday night...upper ridge flattens and moves east in response to
upper trough diving into the northwest US. Surface low develops over
northeast Montana along Arctic front sliding south of out Canada. Flow
ahead of front should keep temperatures up in the usual higher
elevations locations. Otherwise...temperatures near guidance.


Long term...Saturday through Thursday
issued at 206 PM MST Thursday Nov 27 2014

Large upper trough will cross the Pacific northwest
Saturday...bringing a surge of cold air to the northern plains
late Saturday into Saturday night. A strong cold front will drop
south across the County Warning Area Saturday afternoon. Maximum temperatures will be tricky
for Saturday...since it will largely depend on the timing of the
frontal passage. High temperatures across northwest South Dakota may only
be in the 30s...while far southern South Dakota could see highs in
the 60s. As the front drops through the County Warning Area...some light snow will
be possible...mainly across western areas....from Sat night into
Sunday...but just light quantitative precipitation forecast is expected. Sunday looks cold...with
highs only in the teens. Models suggest mainly dry conditions with
moderating temperatures early next week.


Aviation...(for the 00z tafs through 00z Friday evening)
issued at 514 PM MST Thursday Nov 27 2014

VFR conditions are expected through Friday.


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


Short term...helgeson
long term...15

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