AIR MAIL
Where today’s air came from
The air arriving over Darien about 5,000 feet above the ground was over the western Atlantic three days ago, and over the Great Lakes a day ago, about 1,230 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 Maritimes; 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.