AIR MAIL
Where today’s air came from
The air arriving over Bass River about 5,000 feet above the ground was over the North Atlantic three days ago, and over Ontario a day ago, about 1,640 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 790 miles to the northeast; at 10,000 feet, from the Mid-Atlantic. Traced back 72 hours through NOAA’s hourly RAP analyses and the GFS beyond them, nine paths at each of three heights.