The storm likely would be felt in the eastern edge of North Carolina but would have its biggest impact from the Delmarva Peninsula up into Canada, forecasters say
Some meteorologists say a rare combination of events -- Hurricane Sandy, an outbreak of unseasonably cold air, and a strong land-based storm system -- could deliver flooding rains, damaging winds of near-hurricane force, large waves, and even heavy snow inland.
One forecaster said the storm could do a billion dollars damage to the United States.
The storm would come about the same time of year as 1991s so-called Perfect Storm, but AccuWeather meteorologist Alex Sosnowski noted, The Perfect Storm stayed offshore.
Forecasters admit it is too early to know what will happen, and Sosnowski said, Multiple components have to come together for this perfect storm.
But some computer models predict the system will come ashore early next week somewhere along the East Coast.
At 8 a.m. Thursday, the center of Hurricane Sandy was about 75 miles north of the Cuban coast, and the Category 2 storm was moving northward into the Bahamas, with top sustained winds of 105 mph. Sandy is expected to slowly move north through the central Bahamas and then up the East Coast -- but a couple hundred miles off the Georgia and South Carolina shoreline.
In the United States, a tropical storm warning is posted on Floridas East Coast, from near Daytona Beach southward. A tropical storm watch is in effect from the Georgia-Florida border down to near Daytona Beach.
Michael Brennan of the Hurricane Center added, People elsewhere on the east coast of the United States should monitor the progress of Sandy. Carolinas impact
Computer models generally agree that Sandy, as a Category 1 hurricane, will not come ashore in the Carolinas. However, the models consistently have nudged the storms track westward over the last 48 hours, and it now appears as if gusty winds and heavy rain will affect the Outer Banks and possibly the coastal mainland of North Carolina.
Bob Frederick, of the National Weather Service office in Morehead City, says the storms impacts will be felt from Saturday into early Monday.
This long duration of strong winds will likely produce coastal flooding problems, especially for southern Pamlico Sound and the Outer Banks, he said, adding that sound-side flooding is likely Monday as the storm moves north of the area.
He also anticipates 3 or more inches of rain along the Outer Banks, with an inch or more on the mainland.
The computers agree, generally, about Hurricane Sandys path up the coast, off the Outer Banks. After that, theres disagreement.
The Global (GFS) model has predicted Sandy will curve northeast, away from the coast and out to sea. A low pressure system might form in Sandys wake and push up the East Coast as a noreaster, but it would be nothing out of the ordinary for autumn or winter.
However, the European model and other models have predicted that Sandy will become involved with an approaching low pressure system moving across the northern United States. A phenomenon known as baroclinic strengthening could add strength to Sandy.
While the storm would lose its tropical characteristics, its strong winds and heavy rain would spread over a much wider area -- covering hundreds of miles.
The models are predicting Sandy will get caught up in the trough (low pressure) approaching the eastern United States, which will inject a large amount of energy into the storm, said Jeff Masters, a storm specialist with Michigan-based Weather Underground.
Masters says such a storm could have sustained winds of 60 to 70 mph and extremely heavy rain.
Meteorologists refer to this as an atmospheric bomb. said AccuWeathers Sosnowski.
The European computer model predicts the storm will curve northwest and make landfall on the Delaware coast sometime late Monday. Other computer models predict landfall farther north, possibly near New York City.
A merger of storms -- Hurricane Grace and a land-based system -- is what created the so-called Perfect Storm of 1991.
Masters, however, says odds are still against such a storm forming and hitting the East Coast.
Even a snow threat
One other aspect of such a storm would be the chance of heavy snow inland.
The coldest air of the season is predicted to push from Canada into the eastern United States late this weekend. Meteorologists say that if the coastal storm is strong enough, and its precipitation spreads far enough inland, it could fall as snow.
Such an event has happened several times in the past, and the East Coast was hit with a snowstorm last year around Halloween.
The most likely area for snow, depending on where the storm might make landfall, would be in the mountains of Maryland, Pennsylvania and New York.
(The Associated Press contributed. )
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