NEW YORK - A massive winter storm system packing cold air, snow and freezing rain was bearing down on the US East Coast, causing federal and local offices in Washington to close on Monday after it pummeled the central United States over the weekend.

The National Weather Service predicted the storm will bring up to 9 inches (23 cm) of snow to the Washington area. Votes scheduled for Monday in the US House of Representatives and Senate were postponed, and District of Columbia Public Schools have canceled classes.

The storm "is going to be a real mess," said Bruce Sullivan, a senior meteorologist with the National Weather Service in Silver Spring, Maryland.

"The main system is injecting a lot of moisture and cold air out over the Southern Plains," he said. "It's going to bring quite a bit of precipitation."

Rainfall and snow associated with the system stretched over 1,500 miles (2,400 km), from southeastern Colorado to southern Massachusetts, meteorologists said.

About 2,000 flights were canceled and 5,600 were delayed as of early evening on Sunday due to the storm, according to the airline tracking site FlightAware.com.

"Ripple-effect flight delays and cancellations are likely to reach nationwide," said AccuWeather meteorologist Alex Sosnowski.