AIR MAIL
Where today’s air came from
The air arriving over Santa Monica about 5,000 feet above the ground was over southern California three days ago, and over the Great Basin a day ago, about 1,400 miles back along its path. The nine paths traced from around the city fan out, so treat that as a best guess. Near the ground the air came from the California coast; at 10,000 feet, from the Pacific off California. It feels humid. Traced back 72 hours through NOAA’s hourly RAP analyses, nine paths at each of three heights.