AIR MAIL
Where today’s air came from
The air arriving over Gaines about 5,000 feet above the ground was over the western Atlantic three days ago, and over Quebec 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 Quebec; at 10,000 feet, from the western Atlantic. Traced back 72 hours through NOAA’s hourly RAP analyses and the GFS beyond them, nine paths at each of three heights.