AIR MAIL
Where today’s air came from
The air arriving over South Harbor about 5,000 feet above the ground was over Texas three days ago, and over the southern Plains a day ago, about 1,100 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 a point about 480 miles to the southeast; at 10,000 feet, from Texas. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.