Atmosphere Journal Entry
Atmosphere Journal Entry
Busy Hurricane Season Predicted (April 5, 2010)
Hurricane Bill was one of only three Atlantic hurricanes in 2009. NASA.
The 2009 Atlantic hurricane season was mild, with only nine named storms and three hurricanes. But meteorologists predict this year's season will be much busier. AccuWeather forecasts 16 to 18 named storms in the Atlantic. Five of these are expected to be hurricanes, and two or three are likely to make landfall in the United States. The Tropical Meteorology Project at Colorado State University predicts there will be as many as eight hurricanes. The Atlantic season runs from June 1 through November 30.
One reason for the predicted upswing in activity is El Niño, the climate event marked by warmer than normal ocean temperatures in the central and eastern Pacific Ocean along the equator. In 2009, El Niño quieted Atlantic hurricanes by increasing wind shear over the Atlantic Ocean. Strong vertical winds ripped storms apart before they could fully form. But El Niño is now getting weaker and isn't expected to have much influence on this year's hurricanes.
In addition, sea surface temperatures are warmer than normal at tropical latitudes stretching from Africa to the Caribbean. Atlantic hurricanes move from west to east over ocean waters of at least 80°F (27°C). Warmer water means there's more humid air rising from the seas to fuel storms. In a hurricane, an area of low pressure forms at the center of the rising air. Winds begin swirling around the low pressure area. When winds reach 39 mph (62 km/h), the storm becomes a named tropical storm. It's called a hurricane when its winds hit 74 mph (118 km/h).
The U.S. Climate Prediction Center will release its own forecast about the 2010 hurricane season in May.
