。
The store will be closed tomorrow.
Literal
Tomorrow [topic-は] store [subject-が] closed [resultative-ています] [emphasis-よ].
閉まっていますよ uses ~ている in the resultative sense — 'is in the state of being closed.' The よ warns the listener — 'just so you know, it'll be closed.' 閉まる is intransitive ('to close'), marking the store as the subject.