Adios, La Nina?

(CBS)  U.S. space and ocean monitors think it's time to say good-bye to La Nina, the weather pattern that has dominated the globe for the past two years and is blamed for increased hurricanes and drought in the United States, NASA said Tuesday.

Other experts note La Nina has faded before, only to come back.

What happens affects Americans because La Nina is linked to longer, stronger tornado and hurricane seasons and to deep drought in some regions.

La Nina, a huge pool of cold water off the Pacific Coast, "appears to be on its last legs" and will have a difficult time sustaining itself much longer, NASA climate researchers said.

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They say La Nina's two-year reign as the nation’s major catastrophic weather maker could be history by August.

La Nina’s cold water pushes the jet stream further north, leaving more warm and dry air to create drought in the south, and giving hurricanes more room to rumble up the Atlantic Coast.

Anyone who’s lived through the floods and hurricanes of the last couple of years would be very happy to bid La Nina good-bye.

The problem is that the government’s official forecasters are not at NASA, they’re at the National Weather Service, a branch of the National Oceanic and Atmospheric Administration (NOAA).

NOAA Researcher Vernon Kousky, says, "There has been a trend towards the weakening of La Nina, taking that one step farther and saying that the La Nina is over with is probably a little bit premature at this point."

He adds, "We would think that we were getting close to the end, but it is not uncommon, for it to last another year."

Both agencies do agree, nothing will happen before this August. That is not the kind of forecast those living in the dry, dusty, choking grip of La Nina were hoping to hear.

Last month, NOAA said La Nina would linger through the summer, leaving the United States with warmer than normal temperatures, and some Midwestern and Great Plains states with continued extremely dry conditions.

Temperatures soared to their highest levels recorded by NOAA for the January to March period this year.

NAA said its spacecraft had also shown that since March, La Nina's cold surface water was being replaced by water that was 4 degrees warmer than normal off the coast of South America. The current length of time for the warm water patch was beginning to affect the atmosphere by weakening the trade winds off South America, NASA said.

"Should the current trends continue and the winds continue to weaken, there is potential for processes to be set in motion that will allow the warm water in the western Pacific to enhance and expand the surface warming that has already taken place in the eastern Pacific Ocean," the agency said.

NASA said it was watching the switch from colder to warmer water closely to see how it would affect U.S. weather.

Anomalous behavior of the tropical Pacific Ocean had been affecting U.S. weather patterns for the past three years, NASA said.

During the spring of 1997, warm waters off the coast of South America associated with the strongest El Nino on record led to changes in the storm tracks over the Pacific that slammed one storm after another into the U.S. West Coast, causing floods.

NASA said a sudden change was seen in May of 1998 when warm El Nino waters were replaced by the colder waters of La Nina. During last summer's La Nina summer, most of the southern United States experienced drought. La Nina is also blamed for causing more hurricanes to hit land, such as the pair that caused serious flooding in North Carolina last year.