The declaration clears the way for the state to deploy resources, such as the National Guard, to counties and municipalities as they prepare for the storm.
The latest forecast calls for Irene to deliver heavy rain and high winds to an already waterlogged state on Sunday.
Christie says the current track calls for New Jersey to face a “serious, significant event.”
Christie is considering mandatory evacuations. However, the governor is asking people not to go to the Jersey shore this weekend and for those with rental properties to leave Thursday or Friday.
Christie spoke at the State Police Regional Operations Intelligence Center in Ewing.
Meanwhile, Mayor Michael Bloomberg on Thursday urged New York City residents living in low-lying areas to line up a place to stay on high ground ahead of a possible evacuation this weekend due to the hurricane.
Bloomberg said that he expected to make a decision by late Friday whether residents in the city’s so-called “Zone-A” would need to evacuate ahead of the storm that’s now expected to hit the city Sunday. That zone includes neighborhoods along the coast, such as Battery Park City in lower Manhattan, Coney Island in Brooklyn and Far Rockaway in Queens.
“The timing is a little bit up in the air,” he said. “We want to get as close as we can to the actual event, to make sure we don’t do something unnecessary, but there is a point at which we have to, and the logistics require just going ahead.”
Residents in the zone areas should begin moving items to upper floors and gathering important documents now as a precaution, the mayor said. A network of shelters would be available during any evacuation, but Bloomberg suggested that residents with friends and relatives in safer areas of the city ask if they might be able to stay with them if forced to leave home.
Bloomberg said he would issue an executive order instituting a forced evacuation only in the worst of circumstances. A suggested evacuation is more likely, he said.
The city already has crews working to clean out some of the 143,000 catch basins in the metropolis to help with street drainage. Bloomberg said that nearly $2 billion in sewer upgrades over the last decade would also help reduce flooding.
The city has moved boats to police station houses in low-lying areas, hired emergency forest contractors and topped off hospital emergency generators with fuel in anticipation of the storm. Department of Sanitation workers have been asked to be on the look out for any street debris that could clog drainage.
North of the city in the Hudson River valley, Ulster County Executive Mike Hein asked city and state officials to authorize releases from two massive reservoirs that provide drinking water to the city — a move meant to free up storage space and reduce flooding downstream if the storm dumps heavy rain.
The Ashokan Reservoir is at 94 percent capacity and the Rondout Reservoir at 97 percent, Hein said.
Bloomberg said that while Long Island could face a Category 2 hurricane, New York City is not expected to be struck by the brunt of it. Instead, forecasts call for the city to see tropical storm conditions with heavy rains and winds of 60 mph or more, he said.
Months after the mayor faced a public uproar over a slow clean-up following a day-after-Christmas storm, he said that the city’s emergency-response agencies were making sure that they would have adequate staff on hand over the weekend. Deputy Mayor for Operations Cas Holloway, who recently took over the role, said that the Department of Sanitation had already positioned equipment to speed the city’s storm response.
Bloomberg said that public hospitals had already stocked up on food and medical supplies in case deliveries are disrupted, and the Department for the Aging planned to deliver Sunday’s meals on Saturday to homebound seniors.
The city is also reviewing flood contingencies for the U.S. Open tennis tournament, which is scheduled to begin Monday in Queens.