AIR MAIL
Where today’s air came from
The air arriving over Indian Lake about 5,000 feet above the ground was over the Gulf Coast three days ago, and over Texas a day ago, about 1,320 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 Ohio Valley; at 10,000 feet, from Texas. Air off the water carries moisture, which is why it feels humid. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.