El Nino signals neutral conditions through autumn

NEW YORK Thu Aug 7, 2008 5:12pm BST

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NEW YORK (Reuters) - Measures of El Nino weather patterns, an unusual warming of Pacific Ocean temperatures, are showing neutral signals, indicating normal weather should last through the autumn, the U.S. Climate Prediction Center said on Thursday.

The El Nino anomaly causes waters in the Pacific to turn abnormally warm. It encourages wind shears that tend to hinder Atlantic storms that could sweep into the Gulf of Mexico and disrupt oil and gas production in the area.

"Based on current atmospheric and oceanic conditions, recent trends, and model forecasts, El Nino-neutral conditions are expected to continue through the Northern Hemisphere Fall 2008," the CPC said in its monthly update on its website.

It added that most recent sea surface temperature (SST) forecasts for the Nino region indicated that neutral conditions should continue into Spring 2009.

"However, due to the positive heat content anomalies in the Pacific Ocean, the development of El Nino cannot be ruled out during the later part of the year," the weather predictor said, adding that chances of development remain low.

As is typical with El Nino neutral conditions, however, the center said, atmospheric and oceanic indicators were mixed.

"Certain areas in the equatorial Pacific Ocean suggest a lingering influence of La Nina and other areas reflect an increase in above-average temperatures," the CPC said.

Less-well-known La Nina means "little girl" in Spanish and often causes cooler-than-usual Pacific water temperatures. Chilly waters can increase hurricane formation in the Atlantic by suppressing wind shears that tear apart smaller storms.

Atmospheric circulation over the western and central tropical Pacific continues to reflect some aspects of La Nina, CPC said.

Returning to El Nino, the forecasters said actual SSTs are not warm enough to support upward movement despite recent increases in sea surface temperature anomalies.

"Collectively, these atmospheric and oceanic anomalies are consistent with El Nino-neutral conditions," the report said.

El Nino, or "little boy" in Spanish, was named after the Christ child. It was first noticed around Christmas time by Latin American anchovy fishermen in the 19th Century.

Its worst impact in recent history came in 1997/98 when it spurred drought in countries like Australia and Indonesia, while spawning floods in Peru and Ecuador.

(Reporting by Carole Vaporean. Additional reporting by Rene Pastor; Editing by Marguerita Choy)

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