WASHINGTON (AP) -- Much of the U.S. East Coast has a good chance of getting blasted by gale-force winds, flooding, heavy rain and maybe even snow early next week by an unusual hybrid of hurricane and winter storm, federal and private forecasters say.
Though still projecting several days ahead of Halloween week, the computer models are spooking meteorologists. Government scientists said Wednesday the storm has a 70 percent chance of smacking the Northeast and mid-Atlantic.
Hurricane Sandy in the Caribbean, an early winter storm in the West, and a blast of arctic air from the North are predicted to collide, sloshing and parking over the country's most populous coastal corridor starting Sunday. The worst of it should peak early Tuesday, but it will stretch into midweek, forecasters say.
"It'll be a rough couple days from Hatteras up to Cape Cod," said forecaster Jim Cisco of the National Oceanic and Atmospheric Administration prediction center in College Park, Md. "We don't have many modern precedents for what the models are suggesting."
It is likely to hit during a full moon when tides are near their highest, increasing coastal flooding potential, NOAA forecasts warn. And with some trees still leafy and the potential for snow, power outages could last to Election Day, some meteorologists fear. They say it has all the earmarks of a billion-dollar storm.
Some have compared it to the so-called Perfect Storm that struck off the coast of New England in 1991, but Cisco said that one didn't hit as populated an area and is not comparable to what the East Coast may be facing. Nor is it like last year's Halloween storm, which was merely an early snowstorm in the Northeast.
This has much more mess potential because it is a combination of different storm types that could produce a real whopper of weather problems, meteorologists say.
"The Perfect Storm only did $200 million of damage and I'm thinking a billion," said Jeff Masters, meteorology director of the private service Weather Underground. "Yeah, it will be worse."
But this is several days in advance, when weather forecasts are far less accurate. The National Hurricane Center only predicts five days in advance, and on Wednesday their forecasts had what's left of Sandy off the North Carolina coast on Monday. But the hurricane center's chief hurricane specialist, James Franklin, said the threat keeps increasing for "a major impact in the Northeast, New York area. In fact it would be such a big storm that it would affect all of the Northeast."
The forecasts keep getting gloomier and more convincing with every day, several experts said.
Cisco said the chance of the storm smacking the East jumped from 60 percent to 70 percent on Wednesday. Masters was somewhat skeptical on Tuesday, giving the storm scenario just a 40 percent likelihood, but on Wednesday he also upped that to 70 percent. The remaining computer models that previously hadn't shown the merger and mega-storm formation now predict a similar scenario.
The biggest question mark is snow, and that depends on where the remnants of Sandy turn inland. The computer model that has been leading the pack in predicting the hybrid storm has it hitting around Delaware. But another model has the storm hitting closer to Maine. If it hits Delaware, the chances of snow increase in that region. If it hits farther north, chances for snow in the mid-Atlantic and even up to New York are lessened, Masters said.
NOAA's Cisco said he could see the equivalent of several inches of snow or rain in the mid-Atlantic, depending on where the storm ends up. In the mountains, snow may be measured in feet instead of inches.
Associated Press writer Tony Winton contributed to this report from Miami.