AIR MAIL
Where today’s air came from
The air arriving over Wing River about 5,000 feet above the ground was over the Great Basin three days ago, and over the southern Plains a day ago, about 1,450 miles back along its path. It came down from about 11,000 feet up, warming and drying as it sank. Near the ground the air came from a point about 530 miles to the southeast; at 10,000 feet, from the Great Basin. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.