In the Arctic, an ocean is surrounded by continents, while Antarctica is continent surrounded by oceans. These differences in the arrangement of land and water contribute to differences in each polar region’s climate, oceanic and atmospheric circulation patterns, and seasonal and long-term sea ice patterns.

Above-average sea surface temperatures, a natural cycle of increased hurricane activity, and a fading La Nina have influenced the 2011 Atlantic hurricane outlook.

The tornado outbreak across the southern United States in late April 2011 was deadly, devastating, and record breaking. NOAA's "CSI" team is investigating the possible connections between global warming, natural climate patterns, and tornadoes.

Near the Earth’s equator, solar heating is intense year round. Converging trade winds and abundant water vapor all combine to produce a persistent belt of daily showers known as the Intertropical Convergence Zone.

As far back as August 2010, NOAA's seasonal climate models predicted that rainfall would be heavier than normal across Indonesia and Southeast Asia in early 2011. The cause? La Niña.

Natural climate phenomena—the North Atlantic Oscillation & La Niña—can explain much of this winter's temperature patterns across North America.

globes showing pressure patterns during positive and negative phases of the Arctic Oscillation

Large-scale shifting of the weight of the atmosphere between mid- and high latitudes creates climate patterns known as the Arctic and North Atlantic Oscillations. These patterns have a big influence on winter weather in the Eastern U.S.

Drought conditions have become more widespread and severe in the Southwest in the first part of 2011.

Most of the southwestern United States is having a very dry winter. The northern parts of Arizona and New Mexico were clipped by a few drenching storms exiting California in December, but dry conditions are more the norm.

Deep snow that fell across the Great Plains and the Northeast in late January and early February is the latest installment in the second very wintry winter in a row for the eastern U.S.

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