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Area forecast discussion for western South Dakota and northeastern Wyoming 
National Weather Service Rapid City South Dakota
353 am MDT Sat Aug 1 2015

Short through Sunday night
issued at 228 am MDT Sat Aug 1 2015

Broad upper ridging will remain across the western Continental U.S. Through the
remainder of the weekend. An upper wave is cross north central Montana at this time
pushing southeast toward the County Warning Area. Surface trough/frontal boundary has
developed ahead of the wave over eastern Montana. Good return flow over the
County Warning Area is resulting in enough Theta-E advection for elevated storms to
develop from scntrl South Dakota toward Meade/Butte border...and also near
Nemo/Black Hawk. Today...frontal boundary will cross the County Warning Area as
the upper wave pushes through the region. S/SW winds will become
nwrly behind the frontal passage which will be of a dryline than anything
else. Temperatures still expected to rise into the upper 80s to upper
90s. Dewpoints will drop behind the boundary...ending any
prospects for convection through the day from northwest to southeast. By late
afternoon...the only chances for storms will be near the Nebraska
border...and these chances should end by early evening. Drier low
levels will persist into Sunday which will hinder any storm
development. Mostly sunny skies are expected with highs reaching
into the middle 80s to middle 90s.

Long term...Monday through Friday
issued at 228 am MDT Sat Aug 1 2015

Models in decent agreement with the overall pattern through the
week. Ridge breaks down Monday/early Tuesday as weak upper trough
lifts through the central rockies into the plains. East-southeast
low level flow will bring increasing moisture boundary layer
moisture...while surge of middle level moisture arrives with the
trough. May be a few isolated thunderstorms late Monday from the
Black Hills into south central South Dakota. Better chance of
thunderstorms on Tuesday with weak upper trough across the northern
plains. Weak ridging across the area for Wednesday...though
sufficient instability for a few thunderstorms. Chance of storms
will continue through the end of the week as upper trough tracks
across the Pacific northwest/northern rockies.


Aviation...(for the 12z tafs through 12z Sunday morning)
issued at 353 am MDT Sat Aug 1 2015

Isolated rain showers/thunderstorms and rain will be found across the area today...mainly
from the Black Hills into south central South Dakota. Local MVFR
ceilings/IFR visibility with the stronger storms. Otherwise...VFR conditions
expected through tonight.


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


Short term...13
long term...7

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