It would be entirely possible for the smoke from Canadastan to get to NYC without going directly over a location between the two. The wind does not blow in straight lines, it blows in circular patterns (cyclones or anti-cyclones), so the smoke may well have blown off the coast, made a big arc and then blown back again.

During the 2019 fires in Australia, the sky over my house was darkened by smoke from the fires, then cleared, then re-darkened as the smoke cloud was blown back over from out in the Tasman sea. The second time it came over, you could clearly tell the difference by the smell. It smelled of stale smoke, rather than fresh smoke. The fires were nowhere near me that year, but were to the North, East and West (by at least a hundred kilometers in each direction).

Yeah, when I was a kid we always had bags of ammonium nitrate "fertilizer" lying around. If I had known then that it could be used as an explosive I probably wouldn't be alive today, at least not with all my limbs intact...

Ammonium nitrate burns with a yellow flame, but when mixed with other materials it can produce a red smoke. The explosion that occurred in Beirut, Lebanon on August 4, 2020 was caused by a large quantity of ammonium nitrate that had been improperly stored in a warehouse for several years.