AIR MAIL
Where today’s air came from
The air arriving over Stoney Brook about 5,000 feet above the ground was over the central Plains three days ago, and over the southern Plains a day ago, about 1,070 miles back along its path. It came down from about 9,400 feet up, warming and drying as it sank. Near the ground the air came from a point about 460 miles to the south; at 10,000 feet, from the central Plains. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.