This in from Notify NYC:
Notification issued 1/3/14 at 3:55 PM. To facilitate snow removal and underground train storage, all express MTA Subway service will be suspended as of 5:45 PM tonight. Local service will remain in effect. Limited express service may resume tomorrow, Saturday, 1/4/14; however, service can be curtailed or suspended on an individual line or route basis as conditions warrant. Customers are urged to be careful boarding buses and trains, allow extra time if traveling, and to monitor service status at http://www.mta.info for the latest updates.
According to the MTA website, the planned service work that would have diverted Brooklyn bound F trains to the A/C line this weekend has been cancelled. There will be service from Manhattan to York Street in DUMBO.