WASHINGTON -- The storm that is threatening 60 million Americans in the eastern third of the nation with persistent high winds, drenching rains, extreme tides and heavy flooding is not one simple weather system.
Weather experts say it combines Hurricane Sandy, an ordinary cold front and Arctic air. The hurricane is being steered by a giant ridge of air centered over Greenland, blocking its normal path north. The full moon and an expected record low pressure will likely amplify its wrath.
The result is a week-long weather monster that the federal government's top forecaster says is far worse than the sum of its parts.
Weather Underground director Jeff Masters calls it part hurricane, part nor'easter and all trouble.