"An unseasonably cold Pacific low pressure trough will bring periods of wet snow to the 
northern and western mountains from midnight tonight to 6 am mdt Tuesday morning. 
Snowfall accumulations will be mainly above 9000 feet with 4 to 8 inches expected. 
locally heavier amounts are possible. Snowfall below 9000 feet of 1 to 3 inches 
is expected with snow melting as it falls at times on Monday."

– NOAA Riverton, WY today

NOAA is calling for the first snow of the season in Jackson Hole, WY to occur tonight, Monday, and Tuesday.

NOAA is forecasting snow levels as low as 7,500.

4-8″ of snow is forecast above 9,000′.

1-3″ of snow is forecast below 9,000′.

“First Snow! Say it ain’t so! We’re afraid so. Sorry all, the first snow is indeed upon us. A cold front will move in this evening bringing much cooler air, rain, and snow in the higher elevations. Most snow will fall above 9,000 feet, but snow levels will drop to around 7,500 tonight. Winter Weather Advisories are out from midnight tonight until 6 AM Tuesday.” – NOAA Riverton, WY today

WINTER WEATHER ADVISORY for WYOMING:

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
1249 PM MDT Sun Aug 26 2018

....WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO
6 AM MDT TUESDAY...

.An unseasonably cold Pacific low pressure trough will bring
periods of wet snow to the northern and western mountains from
midnight tonight to 6 am mdt Tuesday morning. Snowfall
accumulations will be mainly above 9000 feet with 4 to 8 inches
expected. locally heavier amounts are possible. Snowfall below
9000 feet of 1 to 3 inches is expected with snow melting as it
falls at times on Monday.

Teton and Gros Ventre Mountains-
1249 PM MDT Sun Aug 26 2018

...WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO
6 AM MDT TUESDAY...

* WHAT...Wet snow expected. Total wet snow accumulations of 4 to 8
  inches above 9000 feet, with 1 to 3 inches below 9000 feet.

* WHERE...Teton and Gros Ventre Mountains.

* WHEN...From midnight tonight to 6 AM MDT Tuesday.

* ADDITIONAL DETAILS...Plan on slippery road conditions,
  including during the morning commute on Monday. Expect reduced
  visibilities at times.