The Australian Bureau of Meteorology says the 2011–12 La Nina event has ended. It says key indicators are returning to neutral and weather models suggest that neutral conditions will persist until at least the Southern Hemisphere winter (June-August).
"Key Pacific Ocean indicators are now at neutral levels, with values similar to those last seen in August 2011. Likewise, atmospheric indicators such as cloudiness, trade winds and the Southern Oscillation Index (SOI) have also returned to near-normal values for this time of year," states the bureau.
The bureau says the majority of dynamical models it surveys suggest that tropical Pacific temperatures will continue to warm through the austral autumn and winter months (spring and summer in the Northern hemisphere), with two models approaching warm conditions towards the end of the forecast period.
Juli says: Meteorologists generally believe once La Nina fades, it takes about 20 to 40 days for the weather pattern to return to normal because that's about how long it takes for ocean waters to "settle down." This return to neutral ENSO conditions is a positive development for growing conditions in the U.S. for the spring and summer, although opinions are mixed as to whether El Nino will develop.