The VERY, VERY, very south of Egypt might, at one time, have bordered on the more northern African forests. They were all "rain forests" because that kind of forest could not have existed without almost daily heavy rainfall.
But that is a far cry from an Egyptian "rainforest."
Egypt might have extended its rule farther south than we know of as well. However, by the time there was the culture WE KNOW OF in Egypt, it was desert. We also know this information from the other ancient civilizations at the time...ones the Egyptians warred against.
It IS an interesting topic. Rain forests and whale bones, what could be more interesting for a Sunday night?