New York tornadoes just a sign of things to come

A tornado watch was issued for New York City and the U.S. Northeast on Tuesday. If one is to form, it will be the fourth tornado to hit New York City this summer. Two touched down Sept. 16 and one hit the Bronx in July.

It's been a year of extreme weather, from the so-called Snowmageddon in Washington, D.C. to triple-digit heat in Los Angeles and from hurricanes in the Gulf to floods in Wisconsin; and the extreme weather won't stop any time soon, scientists say.

David Easterling, chief of the Scientific Services Division at the National Oceanic and Atmospheric Administration's Climatic Data Center, said there will be more incidences of extreme weather because the planet is heating up.

What we consider heat waves will become more the norm, Easterling said, and along with heat waves, heavy rainfall and flooding will increase. Plus, while "hurricanes have always been a problem ... the ones that do occur will be more powerful."

The heavy rains and snows can be attributed to the increased heat because the warmer the air is, the more moisture it holds. "Expect more snow," he said, but also expect that the length of the snow season will be reduced.