Jake Corman, the ranking Republican in Pennsylvania’s state Senate who is widely expected to run for governor, has begun inviting donors and others to an announcement next Thursday night. The event is billed as a “special announcement”. Corman’s entry into the race would swell an already big field of Republicans running for governor, double-digits deep and growing as the party searches for a nominee to succeed outgoing Gov. Wolf. Corman, who represents a swath of central Pennsylvania surrounding Penn State’s main campus and has served in the Senate since 1999 after taking over the seat his father held.