An upper-level weather system will approach Wyoming today and will then move across the region on Tuesday.  Expect early sunshine and then clouds will thicken during the afternoon and evening hours.  There will also be a chance for isolated showers and thunderstorms during this time.  Any storms that develop could be strong to severe and capable of producing hail, damaging winds, and brief periods of heavy rain, especially across central and eastern Wyoming.  Temperatures will be warm and above normal through Tuesday, with daytime highs in the 70's to lower 80's.  A trough of low pressure will move into the Pacific Northwest and California on Wednesday and will then remained settled over the region through the end of the work week.  This will funnel subtropical moisture and atmospheric instability into the state of Wyoming during this time.  Expect more clouds than sun with a better chance for showers and thunderstorms on Wednesday, Thursday, and Friday.  Rain could also become heavy at times.  Temperatures will become cooler and closer to average for the second half of the work week.