AIR MAIL
Where today’s air came from
The air arriving over New Braintree about 5,000 feet above the ground was over the Atlantic off the Carolinas three days ago, and over the western Atlantic a day ago, about 1,450 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 North Atlantic; at 10,000 feet, from a point about 340 miles to the south. Traced back 72 hours through NOAA’s hourly RAP analyses and the GFS beyond them, nine paths at each of three heights.