Many ask 'why?' amid wicked winter weather: Joe Rao explains
Meteorologist Joe Rao says that in Westchester alone, some 63 inches of snow has already fallen this year, compared with a normal of 38 inches, which is more typical for this time of year.
One of the major factors is the weather phenomena known as La Nina, a pool of unusually cool water off of the coast of South America that can affect jet stream winds that serve as the pathways for storms. This year, it appears that those pathways are passing directly across the eastern U.S.
A second, major factor is a large dome of cold, high pressure over Greenland called the North Atlantic Oscillation, which can produce an endless flow of unusually cold air. This year's major weather systems appear to be the end result after the cold air from this system interacts with the warmer air from the south.