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Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota
1125 am MDT Friday Sep 19 2014

Short term...today through Saturday night
issued at 220 am MDT Friday Sep 19 2014

Northern stream trough and associated cold front will continue to
advect across the northern plains today...with a stronger
secondary northern stream trough expected into the region later
tonight. Primary frontal boundary has cleared most of the
forecast area...save scentral South Dakota...with lingering Post frontal rain showers over the
far northwest forecast area per ongoing lsa with primary upper trough. Lingering
rain showers will wane this morning over the northwest forecast area...with residual cloud
band shifting southeast across the forecast area today. Weak subsidence will spread
over the forecast area this afternoon...highly limiting precipitation chances...save
for the central/southern bh where diurnal instability and terrain
induced Southern Hills eddy may be sufficient for a rain showers or ts
this afternoon. Cut probability of precipitation across the entire forecast area this
afternoon...leaving only a slight chance mention over the
central/southern bh per lingering Post front moisture. Cooler
conditions expected today most areas...with 70s and 80s for
highs...warmest scentral South Dakota. Secondary/stronger northern stream
upper level trough will push into ND tonight...with a weak ll
reflection supporting a weak positive Theta-E advection surge over NE and
possibly into the far southern forecast area this evening. Have retained a
small pop there for this...however most activity will likely
remain well south of the forecast area. Secondary upper trough will support
another cold front into the forecast area Sat. Lack of sig moisture precludes
any precipitation chances with a dry frontal passage on track. Moderate
cold air advection/pressure rise surge with this system will support increasing
ll momentum fields across the South Dakota plains. Breezy conditions can be
expected as diurnal mixing and steep ll lapse rates will support
downward momentum Transfer Sat afternoon. Near wind advection criteria
likely across the northwest South Dakota plains Sat afternoon. Cooler conds
expected Sat night with lows in the 40s and 50s.

&&

Long term...Sunday through Thursday
issued at 220 am MDT Friday Sep 19 2014

Another upper level ridge will build over the region briefly
Sunday...making for a mild and dry day. Models are in agreement
about a cut-off low moving through early next week. Chances of
showers and thunderstorms return Monday and Tuesday ahead of this
system...with conditions drying out again for the end of the week as
ridging sets up again. Highs in the 70s and lows in the 50s are
expected for the week.

&&

Aviation...(for the 18z tafs through 18z saturday)
issued at 1122 am MDT Friday Sep 19 2014

Breezy north/northwest winds will continue today mainly over the northwest South Dakota
plains. Winds will diminish early this evening. A few -shra/-tsra are
possible this afternoon/evening over the Black Hills and SW/scntrl South Dakota...but VFR
conditions are expected through Sat morning.

&&

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

$$

Short term...jc
long term...pojorlie
aviation...13

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