"AES" wrote in message
...
I could throw in some more than usually uninformed speculation (even for
this group . . . ) about a random dot of frost forming, causing the
airflow to spread out laterally just a bit [...]

That was the theory I came up with too. That should be enough to cause you
concern for whether you're actually correct.

(I didn't post it, because it seemed too outlandish, even for me ).