A strong cold front moved across Star Valley Thursday evening, and in its wake a much cooler air mass now covers Western Wyoming. High pressure now building into the area assures several near perfect weather days ahead.
However, conditions tonight and Saturday morning will be ideal for strong radiational cooling, leading to frost most areas Saturday morning. Temperatures in the typical colder valley locations primarily near the Salt River will likely drop below freezing by midnight, Friday night and possibly bottoming out in the mid to upper 20s by daybreak Saturday.
Obviously this is a threat to frost sensitive vegetables that may have just been planted such as tomatoes etc. These plants should be covered tonight.
Warming is then expected through the Fathers Day weekend, with a lessening frost threat Sunday morning.