Aussie Scientists Note Little Change in La Nina

06:17AM Feb 01, 2012

The Australian Bureau of Meteorology says La Niña conditions showed only small changes over the past two weeks and are expected to maintain an influence upon Australian climate over the coming months.

The Bureau notes sea surface temperatures in the central tropical Pacific cooled slightly, reversing the recent warming trend, but other indicators of La Niña -- such as the Southern Oscillation Index (SOI), trade winds, and cloudiness over the equatorial Pacific Ocean -- have generally remained steady, below their December peak but clearly exceeding La Niña thresholds.

"Climate models surveyed by the Bureau indicate a gradual decline in the strength of the La Niña over the coming months, with most models suggesting a return to neutral conditions during the southern autumn (March-May)," it says.

Additionally, the Bureau says, "La Niña periods are usually, but not always, associated with above-normal rainfall and below-normal daytime temperatures from winter through summer across eastern and northern Australia. Tropical cyclone risk is increased for northern Australia during the cyclone season (November to April), peaking in February and March."

Juli says: The continuation of La Nina is concerning for areas of the country currently seeing drought. Areas of the western Corn Belt and Southern Plains need to see La Nina end to improve rainfall chances. Remember that climatologists believe there is about a 30-day "tail" on the impacts of La Nina. In other words, weather trends typically don't revert out of their "La Nina-type" event until 30 days after La Nina is over. Therefore, the longer La Nina lasts, the longer its impact on the weather.