Winter Weather Coming to Wyoming

Winter Weather Coming to Wyoming

A strong westerly jet stream currently across the northern United States, will  buckle by the end of the coming week which will usher in the first real taste of winter to Wyoming and surrounding states.  The following is a series of 500 mb charts illustrating the forecasted dramatic change in the jet stream.

500 mb Noon Sunday October 18 2020
500 mb Wednesday October 21 2020


500 mb Sunday October 25 2020


While the temperatures will remain mild with mostly dry conditions across Star Valley and surrounding areas through mid week, much colder air and snow will be the rule by the weekend.  There is the potential for significant snowfall across the area with likelihood of feet  in the high mountains  and several inches in the valleys including Star Valley.  The computer models forecast of total snowfall through next weekend is just a first guess as the system event is still 4-5 days away.


Total model snowfall forecast ending Sunday evening October 25 2020

Much colder air will drop temperatures well below normal by the weekend with likely the first below zero temperatures possible in coldest locations by the end of the weekend.  Following is the forecast of temperature departure from normal from the National Weather Service


Forecast of temperatures departure from normal Saturday October 24-Wednesday October 28 2020


For the same forecast period the NWS is highlighting much of Wyoming for significant precipitation, likely snow.

Precipitation departure from normal Saturday October 24 2020 to Wednesday 28 October 2020


As this change is still several days away, details will become clearer by midweek.