Mid-Summer Cool Down/Snow in the Mountains!

Mid-Summer Cool Down/Snow in the Mountains!

The Computer Models have been indicating for the past couple of days that an unusually strong mid July storm system will be taking  aim at Wyoming this coming weekend. While Saturday should be warm and dry, with increasing winds, a strong cold front will cross the state of Wyoming Sunday. Strong winds and falling temperatures on Sunday will accompany the cold front with showers and thundershowers. Snow levels will drop by Sunday evening with the potential for several inches in the highest elevations of Yellowstone NP and the Tetons.

The system that will be providing this abrupt change can be seen on this mornings water vapor image approaching the Aleutian Islands

9am Wednesday July 6 2016

 A series of forecast 500 mb charts tracks the system as it heads toward Wyoming by Sunday.

500 mb 6am July 6 2016

500 mb 6am Saturday July 9 2016

500 mb 6pm Sunday July 10 2016

Surface 6 PM Sunday  July 10 2016

The surface indicates the cold front crossing western Wyoming by Sunday evening with a deepening surface low over northeast Wyoming.

While confidence is now good that unseasonably cool air will affect Star Valley and western Wyoming the amount of actual precipitation is still uncertain.  The models indicate that the heaviest will be in Montana, but at least some is possible across Star Valley.

24 hour forecast precipitation ending 6 pm Monday July 11 2016

Of particular interest is the real possibility of a mid July snow event in the higher elevations. The air mass will be cold enough for snow flakes as low as 7000 ft MSL Sunday night,  several inches could occur in the higher elevations of the Tetons and YNP.

24 hour Snowfall forecast 6pm Monday July 11 2016

Of most concern will be the potential of freezing temperatures in the colder Star Valley locations, most likely on Tuesday morning.  The model indicates that potential in the valleys of much of  Western Wyoming and even Colorado Rocky high mountain valleys.

6am Temperatures Tue July 12 2016