...Possible Freezing Temperatures by Sunday Morning Across the Lower Elevations of Wyoming... .As an early Fall storm moves out of Wyoming this evening, skies will clear tonight into Sunday morning. This will allow heat to radiate out quickly from the already cool airmass...dropping to near or even well below freezing by around sun-up Sunday morning across the lower elevations of Wyoming. Jackson Hole-Star Valley- Including the cities of Jackson, Afton, Alpine, Star Valley Ranch, and Thayne 233 PM MDT Sat Sep 16 2017 ...FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM MDT SUNDAY... The National Weather Service in Riverton has issued a Freeze Warning, which is in effect from midnight tonight to 9 AM MDT Sunday. The Freeze Watch is no longer in effect. * TEMPERATURE...20 to 28 degrees. * IMPACTS...Plants may be damaged or killed by the cold morning temperatures. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Freeze Warning means sub-freezing temperatures are imminent or highly likely. These conditions will kill crops and other sensitive vegetation.