As circus loads out tonight, Dean Street and Sixth Avenue at arena may face traffic freezes and vehicle restrictions

A message issued at 3:07 pm from Terence Kelly, Community Affairs Manager for the Barclays Center:

In the service of a safe and expeditious circus load-out in winter weather conditions, the NYPD will introduce and direct several temporary changes to vehicular traffic on the arena block later this evening.
Beginning at 6:30pm tonight, the arena block will see a heavy volume of circus trailers coming to load out the show. At times, there may be traffic freezes & vehicle restrictions on the following blocks:
- 6th Avenue between Atlantic Avenue & Dean Street
- Dean Street between Flatbush & 6th Avenues
All crosswalks will remain clear and fire lanes will be preserved at all times, with constant contact and coordination w/ FDNY & NYPD 78th Precinct.
Thank you very much for your time and consideration in this matter.

Couldn't they have announced this as a possibility a bit earlier?

Update: photos added 6 pm