Forecasters are predicting that Hurricane Sandy will meet up with a winter storm, creating a rare thing that they are calling "Frankenstorm":

Government forecasters on Thursday upped the odds of a major weather mess, now saying there's a 90 percent chance that the East will get steady gale-force winds, heavy rain, flooding and maybe snow starting Sunday and stretching past Halloween on Wednesday.

Meteorologists say it is likely to cause $1 billion in damages.

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One of the more messy aspects of the expected storm is that it just won't leave. The worst of it should peak early Tuesday, but it will stretch into midweek, forecasters say. Weather may start clearing in the mid-Atlantic the day after Halloween and Nov. 2 in the Northeast, Cisco said.

"It's almost a weeklong, five-day, six-day event," Cisco said Thursday from NOAA's northern storm forecast center in College Park, Md. "It's going to be a widespread serious storm."

With every hour, meteorologists are getting more confident that this storm is going to be bad and they're able to focus their forecasts more.

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Both private and federal meteorologists are calling this a storm that will likely go down in the history books.

"We don't have many modern precedents for what the models are suggesting," Cisco said.

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.

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.

"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."

Lovely.