La Nina is a cooling of water in the tropical Pacific ocean, the opposite of the warm-water condition known as El Nino.
The federal Climate Prediction Center said a transition from La Nina to neutral conditions occurred during June as sea surface temperatures returned to near average conditions.
The transition to a neutral condition could be beneficial along the East and Gulf coasts with hurricane season under way, as the chances for the continental U.S. and the Caribbean Islands to experience a hurricane are higher during La Nina.
However, the forecast also noted that, as in past transitions first reported from changes in sea surface temperatures, La Nina's effects can linger in the atmospheric circulation, but with diminishing strength.
The National Oceanic and Atmospheric Administration's Atlantic hurricane outlook issued in May calls for 12 to 16 named storms including 6 to 9 hurricanes. Currently the second named storm of the season, Bertha, is churning in the mid-Atlantic.
While the forecast calls for neutral conditions to continue into the fall, the Climate Prediction Center said it could not rule out a change at that time, as El Nino-La Nina switches often occur in the second half of a year.
A change in the fall could affect winter weather across the country. Winters during El Nino periods tend to have a strong storm track across the southern part of the United States and milder-than-average conditions with less storminess across the North. A La Nina winter tends to be colder and stormier than average across the North and warmer and less stormy conditions across the South.