Wet season favoured for most of Australia

James Nason, 25/10/2011

Chances of exceeding median rainfall Nov-Jan - click on image below article to view in larger format.The latest seasonal climate outlook for Australia paints a picture to gladden the hearts of cattle producers across large sections of the country.

The Bureau of Meteorology is forecasting above-average rainfall across northern, eastern and south west Australia for the next three months, and far less extreme weather conditions than those delivered by last summer's dam-bursting La Nina pattern.

National Climate Centre forecaster Andrew Watkins told Beef Central this morning that the recently formed La Nina was far weaker than its extreme predecessor, which caused intense storm activity and widespread flooding across the country last summer.

The result was likely to be higher than normal rainfall but less chance of the heavy impacts that occurred last year.

“When you have a very strong La Nina, you tend to have very strong impacts – wide scale, widespread, very heavy rainfall,” Mr Watkins said.

“When you get a La Nina that is like this one, locally you can get very heavy falls and extremely rainfall and localised flooding, but you tend not to get the really widespread, very heavy rain that we saw last year.”

The official forecast for November 2011 to January 2012 is for  a wetter than normal season  over large parts of northern, eastern and southwest Australia.

The chances of receiving above median rainfall during the November to January period are between 60% and 80% over most of the NT, south and west Queensland, most of NSW, SA, northeast and southwest WA.

The largest odds occur in a region on the border between NSW and Queensland and over northern parts of the NT. Such odds mean that for every ten years with similar ocean patterns to those currently observed, about six to eight November to January periods would be expected to be wetter than average over these areas, while about two to four would be drier.

In contrast, the chances of receiving above normal rainfall is between 35% and 40% over the western part of Tasmania. In other words, the chances of below normal rainfall range from 60% to 65%.

Over the rest of the country, the chances of a drier or wetter November to January are roughly equal.

Driving the forecast for a wet summer was the combination of the recently formed La Nina in the Pacific as well as warmer southern Indian Ocean temperatures.

“Last year we had a raging La Nina and a slightly warm Indian Ocean, and this year we have a really warm Indian Ocean and fairly weak La Nina,” Mr Watkins said.

“They have flipped over to give us an outlook that is vaguely similar to last year.

“Definitely the odds are there for above normal rainfall across large parts of Australia.”


Your email address will not be published. Required fields are marked *

Your comment will not appear until it has been moderated.
Contributions that contravene our Comments Policy will not be published.


Get Beef Central's news headlines emailed to you -