NEW YORK (AP) — As Hurricane Sandy spun up the East Coast, New York residents of some flood-prone areas were told today to evacuate and transit officials prepared for the unusual step of shutting down service. Governor Andrew Cuomo issued an order telling the Metropolitan Transportation Authority to prepare for possibly shutting down all service on subways, buses and commuter rail lines. A decision on whether to cut off service is to be made Sunday. "Suspending the largest transportation system in North America is a monumental effort, and it is imperative that we start the process before we make a final decision, and before the worst of Hurricane Sandy reaches us," MTA Chairman and CEO Joseph J. Lhota said in a statement. When the MTA halted service during Hurricane Irene in August 2011 it was the first such weather-related shutdown in the agency's history. Hurricane Sandy has been making its way toward the eastern seaboard, and could combine with a storm system from the west and cold air from Canada to bring heavy rains and strong winds Monday and Tuesday. The severity of this rare convergence was unclear today. New York City Mayor Michael Bloomberg said there were no evacuation orders in effect for the city. But he said shelters will be opened in 65 public schools on Sunday for residents of low-lying areas who are concerned that their homes may be affected by flooding or power outages. Bloomberg said a decision on whether to close schools Monday would be made tomorrow.