BOSTON (AP) — Outgoing U.S. Sen. John Kerry is planning a farewell tour of Massachusetts before formally stepping down from the seat he’s held for nearly three decades.

Kerry will make stops in Springfield and Worcester on Thursday before giving a farewell address at Boston’s Faneuil Hall to thank voters who have elected him to the Senate since his first win in 1984.

The tour comes a day before Kerry steps down to become Secretary of State.

On Wednesday, Gov. Deval Patrick appointed former chief-of-staff William “Mo” Cowan to serve as interim senator until a special election in June.

The only announced candidate is Democratic U.S. Rep. Edward Markey. Democratic Congressman Stephen Lynch is expected to announce his candidacy Thursday.

Officials close to Scott Brown say the former Republican senator is “leaning strongly” toward running.

Copyright 2013 The Associated Press.