Sub Zero Temperatures on the Way

Subzero cold is on the way to much of western Wyoming including Star Valley. In the wake of the current storm, skies should clear late Friday into Saturday.  This will allow temperatures to plummet by Saturday morning. Below zero readings should be common with the typically coldest valley locations possibly to 10 below.

However a major adjustment to the jet stream pattern across the Pacific Ocean is expected to lead to even colder temperatures by next week. 

The following 500 mb charts graphically illustrate the expected change.

Noon Dec 25 2014

Noon Dec 27 2014

Noon Dec 29  2014

This large high pressure ridge off the west coast will allow very cold air to pour south from Canada into the Western States including western Wyoming.

By mid day Saturday the models depict the cold air over Canada heading south toward the western States.

By noon Monday  a cold polar high pressure is spreading the airmass south into the area.

By Tuesday night bitter cold has engulfed all of Wyoming and surrounding states

As of now it appears that by Wednesday morning if not before the mercury will dip to 10 to 20 below zero  in many areas of western Wyoming and possibly 30 below in the typically coldest locations.