Raining cats and dogs

[Patti Kurtz]

I know this has been addressed before as part of a discussion on folk
etymology, but is there any clear source or origin for the phrase "raining
cats and dogs"?  On the Internet, I found lots of possibilities, including
mythological origins, but no one seemed to be very certain of where the
phrase may have come from.  And I don't buy the suggestion that dogs and
cats would drown in a sudden rain and float down the streets, making it look
as if they had fallen from the sky-- dogs and cats can usually get away from
rain pretty quickly if they want to.

Thanks.

Patti Kurtz
Heidelberg College