I don't often post emails sent to me, but I thought this was an interesting topic and worth showing since it is rather timely as well. If the writer wants me to include his/her name/pseudonym on post, just leave a message or send me an email.
"A search for Af Bri, that name to which we address our first entreaty for rain in Tefilas Geshem, shows up inthe Angel Dictionary on Wicca and Wikipedia.
Do you know any info about the origins of this Af Briin Judaism or can you PROVE its pagan origins, to the exclusion of the defense that they got it from us? I cannot find the Jewish roots of this nor when or whereor why it entered the liturgy."
As far as I know, Af Bri first enters Judaism and the world at large at the introduction in the Tefilas Geshem liturgy written by Rabbi Elazar HaKallir (there are different spellings online if you wish to search, "ha kallir, hakalir, etc.) at around the 6th to 8th centuries CE. It actually very possibly is a poetic way of referring to the more well known angel(s) of rain of the day. If you break down the name, Af, meaning anger and Bri, meaning health, it describes the two general types of ways in which rain can be delivered (assuming in a theistic cause for the weather, of course). At the very least, the name sounds very Hebraic.
The first Jewish angel of rain is probably "Matarel" who is mentioned in the Book of Enoch (circa 2nd cent BCE) and who's etymology is simple. "Matar" means rain and "el" means "god or power." Most angels of that time in Judaism were named as their specific "mission" and ended in "el." Other names for the Jewish angel of rain were things like Matriel, Matariel, and Batarel which are clear derivations. A couple of others, Ridya and Zalbesal I found but I haven't looked up their origins.