The El Nino that has been driving storms into California, helping ease the drought in the Southeast and keeping weather dry in other areas is expected to persist through spring.

Storms spawned by the Pacific Ocean phenomenon have battered California in recent weeks. At the same time, El Nino has altered wind flow in the atmosphere, bringing more moisture to the Gulf Coast from Texas to Georgia.

But the Ohio Valley remains dry, the National Oceanic and Atmospheric Administration reported yesterday.

Temperature and air pressure over the Pacific indicate El Nino is in its mature stage, NOAA's Climate Prediction Center reported. It is expected to continue through spring, but "thereafter, the forecasts are more uncertain."

The Climate Prediction Center said sea surface temperatures in the equatorial Pacific remained more than 2 degrees Fahrenheit above average last month.

This can affect the atmosphere above the ocean, disrupting the powerful winds that steer weather patterns and potentially can affect weather worldwide.

"Typically, El Nino impacts on the U.S. are strongest during the winter and early spring due to changes in the jet stream and the pattern of storm activity," said Vernon Kousky, lead El Nino forecaster.

The forecasters say El Nino is likely to continue producing drier-than-average conditions around the Ohio Valley states and northern Rockies; wetter-than-average conditions along much of the southern tier of the nation; and higher-than-average temperatures across the northern tier states and southern and southeastern Alaska.

Storms in recent weeks have helped ease drought conditions along the Gulf Coast and Southeast from Texas through Georgia.