AIR MAIL
Where today’s air came from
The air arriving over Garnes about 5,000 feet above the ground was over the northern Plains three days ago, and over the central Plains a day ago, about 1,520 miles back along its path. The nine paths traced from around the city fan out, so treat that as a best guess. It came down from about 11,500 feet up, warming and drying as it sank. Near the ground the air came from the southern Plains; at 10,000 feet, from Texas. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.