WASHINGTON (AP) -- The La Nina climate phenomenon under way in the Pacific Ocean has weakened but is expected to continue at least through midsummer, government weather forecasters said Thursday.
La Nina is a periodic cooling of the tropical Pacific sea surface which reduces rainfall in the region and can affect weather around the world.
Its primary effect over the United States in spring and summer is below-average rainfall over parts of the Southwest, extending from Texas to Nevada.
It tends to produce above-average rains over Indonesia.
The National Oceanic and Atmospheric Administration said sea surface temperatures across the central and east-central equatorial Pacific were about 1.8 degrees Fahrenheit (1 degree Celsius) below average.
In December, the cool areas ranged from 1.8 degrees Fahrenheit to 7.2 degrees Fahrenheit (4 degrees Celsius) below normal.
Despite this improvement, forecasters said they expect La Nina to continue through July.
La Nina is the opposite of the better known El Nino condition in which the equatorial Pacific becomes warmer than normal.
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