MacRumors readers Daniel (photo above) and Matthew let us know that Apple had posted a new digital sign overnight at the location of their upcoming Grand Central Station store. The sign reads "Apple Store, Grand Central. Arriving Soon."
Update: The New York Post reports that Apple is planning to open the new store on Friday, December 9th, but no official announcement has yet been made.
Update 2: techfootnote has posted a brief video showing the flipping animation on the new signage. Additional messages beyond the "Arriving Soon" note include "Grand Central Has Added Another Stop." and "Get Your Train(ing) Here."