For city, try:
^[a-zA-Z]{2,}$
But ... "St.Louis"? "New York"? You might want to expand your specification.
Similarly, streets are fraught with problems: spaces are very common, "42nd St." is very possible, and so forth. You probably don't want to use a Regex for either of these - there are too many "edge cases" which will frustrate users trying to enter the data they
know is correct but your rules don't accept.
For cities, I'd use a list (or free text), for streets I'd allow free text.