AIR MAIL
Where today’s air came from
The air arriving over Skandia about 5,000 feet above the ground was over the Mississippi Valley three days ago, and over Texas a day ago, about 1,140 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 Ozarks; at 10,000 feet, from a point about 750 miles to the south. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.