A series of fast-moving weather systems and daytime heating will trigger isolated to scattered shower and thunderstorm activity today and Friday.  Any storms that develop could produce brief periods of heavy rain as well as gusty winds and lots of lightning.  However, no major travel concerns are expected.  We will also see variably cloudy skies with mild and near or slightly above normal temperatures.  Daytime highs will remain in the 50's and 60's.  A stronger weather system and cool front will approach the state of Wyoming on Saturday.  Showers and thunderstorms will be possible throughout western parts of the state during the day, while there will be just a small chance for a passing shower or thunderstorm elsewhere.  Rain showers will then be likely Saturday night into Sunday for lower elevations and rain could become heavy at times.  For higher elevations (above 7,500 feet) and the state's mountains, expect wet snow during this time.  Temperatures will remain mild and near or slightly above normal on Saturday and then cooler temperatures arrive by Sunday.