AIR MAIL
Where today’s air came from
The air arriving over Freeman about 5,000 feet above the ground was over the southern Plains three days ago, about 860 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 9,100 feet up, warming and drying as it sank. Near the ground the air came from a point about 350 miles to the south; at 10,000 feet, from the northern Plains. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.