I had a beautiful flight yesterday (Saturday) in and around the foothills of the Rockies, west of Denver. Perfect weather, blue skies & probably 100 miles visibility. Same blue skies this morning, but looking out my back door the trees were swinging and bending and the sky was populated with this... a very good sign that it's not a good day to go flying downwind, in or around the mountains. Those ragged ones, along with the beautiful lenticulars are talking to me loud & clear - "Don't even think about it". Weather moving in with a little snow tonight.