La Nina returns, bringing more severe weather to the US

AFP Yahoo News 9 Sep 11;

The weather phenomenon known as La Nina is returning for another season, likely bringing more drought, heavy rains and severe weather to some parts of the world, US forecasters said Thursday.

Experts at the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center upgraded last month's La Nina Watch to a La Nina Advisory, the agency said in a statement.

The back-to-back emergence of the trend -- which causes cooler than average temperatures in the Pacific Ocean -- is not unheard of and happens about half the time, NOAA said.

"La Nina, which contributed to extreme weather around the globe during the first half of 2011, has re-emerged in the tropical Pacific Ocean and is forecast to gradually strengthen and continue into winter," it said.

The June 2010 to May 2011 La Nina "contributed to record winter snowfall, spring flooding and drought across the United States, as well as other extreme weather events throughout the world, such as heavy rain in Australia and an extremely dry equatorial eastern Africa."

Over 12 million people across the Horn of Africa are reeling from the region's worst drought in decades, which led the United Nations in July to declare the first famine this century.

The weather pattern was blamed for extremely heavy downpours in Australia, Southeast Asia and South America over late 2010 and early 2011.

"This means drought is likely to continue in the drought-stricken states of Texas, Oklahoma and New Mexico," said Mike Halpert, deputy director of the Climate Prediction Center.

The northwestern United States can brace for a colder winter than usual while southern US states should see a warming trend, he said.

La Nina Gets Reborn, Will Strengthen During Winter: CPC
Rene Pastor PlanetArk 9 Sep 11;

La Nina Gets Reborn, Will Strengthen During Winter: CPC Photo: Reuters/Eric Miller
A man helps push his neighbor's car up a hill after more than twelve inches of snow fell in Minneapolis, February 21, 2011.
Photo: Reuters/Eric Miller

The dreaded La Nina weather anomaly, blamed for both drought and record snowfall in the U.S., has returned and will garner strength during the coming winter, the Climate Prediction Center forecast Thursday.

"While it is not yet clear what the ultimate strength of this La Nina will be, La Nina conditions have returned and are expected to gradually strengthen and continue into the Northern Hemisphere winter (of) 2011-12," the CPC said in a monthly update.

It said waters in the eastern half of the equatorial Pacific Ocean cooled in August, and the "oceanic and atmospheric patterns reflect the return of La Nina conditions."

The CPC is an office under the U.S. National Oceanic Atmospheric Administration. It issues monthly reports on the El Nino and La Nina weather phenomena. Both weather patterns often follow one another in the Pacific.

El Nino is an abnormal warming of waters in the Pacific and led to the failure of India's vital monsoon in 2009/10.

La Nina is the opposite and is often linked to the ramping up of storms in the Atlantic basin which threaten oil rigs in the Gulf of Mexico.

It has already been an active storm season, with Hurricane Irene running up the U.S. East Coast and wreaking havoc through heavy rains and floods from North Carolina to Vermont bordering Canada.

Currently, three systems were being tracked in the Atlantic Ocean and Caribbean Sea which may threaten the U.S. Gulf and East Coasts.

La Nina was blamed in part for the severe snow storms which struck the U.S. last winter and the worst drought in a century which has ravaged Texas and swathes of the southwestern part of the country.

El Nino means "little boy" in Spanish and was named after the Christ child when it was first observed by Latin American anchovy fishermen one Christmastime in the 19th Century. La Nina means "little girl" in Spanish.

(Editing by John Picinich)