Sahih Bukhari Volume 9, Book 87, Hadith Number 163.

Narrated By Salim’s father : The Prophet said, “I saw (in a dream) a black woman with unkempt hair going out of Medina and settling in Mahai’a. I interpreted that as (a symbol of) epidemic of Medina being transferred to Mahai’a, namely, Al-Juhfa.”