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Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota 
340 am MDT Sat Jul 5 2008 


Discussion...08z surface analysis shows trough of low pressure from 
eastern Montana trhough eastern Wyoming into eastern Colorado with a 
low pressure center over southeastern Montana. WV imagery shows 
upper trough crossing central Montana. 


The upper level ridge will shift east and break down today in 
response to the upper trough approaching the northern plains...and a 
cold front will cross western South Dakota. Temperatures will rise 
into the 90s ahead of the cold front over western South Dakota and 
ml cape will rise to 1500-3500 j/kg. Very warm middle level 
temperatures will tend to keep a lid on the convection for a while 
today...but with large scale ascent increasing ahead of the 
approaching trough and convergence along the surface front...expect 
a few storms to be able to break the cap. Sufficient shear exists 
for supercells to develop but expect severe storms to remain rather 
isolated. 


Temperatures will be slightly cooler on Sunday...with chance of 
afternoon thunderstorms. Models continue to bring a strong shortwave 
across the area Sunday night...leading to the best chance of 
showers/thunderstorms. Shear profiles indicate that some severe 
thunderstorms will be possible Sun afternoon/evening over northeastern 
Wyoming and northwestern South Dakota. 


The upper wave will continue to push across the County Warning Area Monday morning 
bringing showers and storms mainly across the South Dakota plains. 
The precipitation will shift into central to eastern South Dakota by Monday 
afternoon though some isolated storms may still fire over the hills 
and the adjacent plains. 


Extended...upper ridge builds over the western Continental U.S. For the middle 
into the end of the upcoming work week...bringing warm temperatures 
to the area. A few short waves will move through the 
ridge...bringing occasional slight chances of thunderstorms. 


&& 


Aviation...isolated thunderstorms and rain will be possible through this evening over 
parts of the area. Otherwise...VFR conditions are expected. 


&& 


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


$$