A cold front and weather system will move out of the region today and very cold Arctic high pressure will take its place.  Flurries or light snow will be possible into the early afternoon hours across southeastern Wyoming, while conditions stay mainly dry throughout the rest of the state.  Winds could be strong and gusty at times across southwestern and south-central portions of the state, which could create some areas of blowing snow and reduced visibility.  Temperatures will be bitterly cold today, with daytime highs staying below or near zero.  Overnight lows will drop into the negative teens and 20's, while the western, central, and southern valleys will see temperatures drop anywhere between -20 and -30.  Wind chill values will be even colder.  High pressure will control the weather on Wednesday and much of the day on Thursday.  Expect partly to mostly sunny skies, breezy to gusty winds, and mainly dry weather conditions.   Temperatures will be not as cold on Wednesday, but it will still be very cold.  A gradual warming trend continues on Thursday, however, temperatures will remain colder than normal.  A passing weather system could bring flurries or light snow to southeastern Wyoming on Thursday night.