Why Sandy is expected to be a historic storm

'Frankenstorm' set to impact mid-Atlantic, northeast

By Max Mayfield - Hurricane Specialist
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MIAMI - The center of Hurricane Sandy is forecast to track generally to the north-northeast for the next two to three days but then turn back toward the northwest and make landfall on the U.S. east coast. 

Exactly where landfall occurs is uncertain and people should not focus on the exact track this far out. 

Regardless of where the center eventually crosses the coast, significant impacts will be felt from the Mid-Atlantic States into New England.

Sandy's expanding wind field could result in millions of people losing power.  The strongest winds near the center when it makes landfall in the U.S. will not be as strong as when Sandy moved over Cuba and the Bahamas, but history teaches that it doesn't take hurricane force winds to result in power outages. 

It is significant to note that Sandy will make landfall on a track that is nearly perpendicular to the coastline.  Hurricanes typically make landfall in the Northeast on a track that is more parallel to the coast.  Sandy's large size will result in storm surge over a large area and the more perpendicular track means areas near and to the north of the landfall point will get the highest storm surge.  Also, Sandy's large wind field means the wave action will be felt to some extent along nearly the entire east coast, with the biggest impacts being felt from the Outer Banks into New England.

Sandy will not be just a coastal event.  The strong winds and rain will spread well inland.  Heavy rains will spread over large areas and will cause inland flooding more widespread than what was experienced last year from Hurricane Irene. 

Sandy will also transform from a tropical cyclone into an extratropical (winter storm-like) cyclone.  This will not lessen the impacts.  In fact, there is potential for heavy snow with maximum amounts greater than one foot and possible amounts near two feet over the higher elevations of the Appalachians. 

The National Hurricane Center (NHC) is tasked with writing the advisories on Sandy while the storm is a tropical cyclone.  The transition to extratropical is not an instantaneous event, but a gradual process.  At some point, big picture responsibility for Sandy will shift from the NHC to the Hydro-meteorological Prediction Center (HPC) along with the Ocean Prediction Center (OPC) located in College Park, MD.  The HPC forecasters have expertise in rain and snow forecasting and the OPC forecasters are experts in marine forecasting.

No matter what you call Sandy, it will be a historic event due to the impacts on millions of people from the combination of its large and strong wind field, angle of attack, coastal effects, heavy rain and snow, and power outages over an extensive area.