AIR MAIL
Where today’s air came from
The air arriving over Alma about 5,000 feet above the ground was over the southern Plains three days ago, and over the central Plains a day ago, about 1,150 miles back along its path. Most of the nine paths traced from around the city agree. It rose from near the ground on the way. Near the ground the air came from the southern Plains; at 10,000 feet, from southern California. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.