AIR MAIL
Where today’s air came from
The air arriving over North Germany about 5,000 feet above the ground was over the southern Rockies three days ago, and over the southern Plains a day ago, about 1,300 miles back along its path. It came down from about 13,900 feet up, warming and drying as it sank. Near the ground the air came from a point about 520 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.