La Niña weather pattern likely to last for some months – UN agency

La Niña weather pattern likely to last for some months – UN agency

The current La Niña weather pattern is expected to strengthen and continue through the middle of the year, bringing wetter conditions to Australia and the western Pacific and a drier climate to the Americas, the United Nations World Meteorological Agency (WMO) reported today.

In its latest forecast, the WMO states that the latest La Niña – which began in the third quarter of 2007 – has picked up strength in the past three months, with sea surface temperatures now about 1.5 to 2 degrees Celsius colder than average over large parts of the eastern and central equatorial Pacific Ocean.

“This La Niña is in the mid-range of past historically recorded events, but the slight further cooling in recent months will likely place it on the stronger side of the middle range,” the agency said in a press release.

During a La Niña pattern, the cooler sea surface temperatures in the eastern Pacific shapes weather conditions across much of the world: heavy rain and thunderstorms, for example, become much more frequent in the western Pacific. It is the opposite of the El Niño phenomenon, which is considered to have ended its current cycle last year.

The agency noted that La Niña has already begun influencing climate patterns over the last six months in the Equatorial Pacific and across the Indian Ocean, Asia, Africa and the Americas.

WMO said it was rare for a La Niña event to continue for two years or more, although this did occur from early 1998 to early 2000. The most likely current scenario is that neither La Niña nor El Niño will prevail from the latter stages of this year.