AIR MAIL
Where today’s air came from
The air arriving over Utica about 5,000 feet above the ground was over the southern Plains three days ago, about 910 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 12,400 feet up, warming and drying as it sank. Near the ground the air came from the Great Lakes; at 10,000 feet, from the northern Plains. It has stayed over land, which is why it feels dry. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.