NT Seasonal Rainfall Outlook: probabilities for October to December 2004, issued 16th September 2004

Neutral outlook for start of wet season

The chances of accumulating at least average rain over the first three months of the northern wet season, are mostly close to 50% in the NT, the Bureau of Meteorology announced today.

probability of exceeding median rainfall - click on the map for a larger version of the map

For the October to December period, the chances of above median rainfall are slightly below 50% in the north of the NT, and slightly above 50% in the south. So in years with ocean patterns like the current, about five October to December periods out of ten are expected to be drier than average across the Territory, with about five out of ten being wetter.

The current pattern of outlook probabilities is due to recent temperature patterns in both the Pacific and Indian Oceans.

Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During the December quarter, history shows this influence to be moderately consistent across much of the NT (see background information).

The chance of a late-developing El Niño event increased over the past month, with several but not all indicators reaching their El Ni˜o thresholds. The mounting evidence includes warming of the central Pacific, reduced Trade Winds in the same area and continued negative values of the Southern Oscillation Index (SOI) which came in at –8 for August. The approximate SOI for the 30 days ending 13th September was –3.

For routine updates on the latest data relating to El Niño, together with details on what the phenomenon is and how it has affected Australia in the past, see the El Niño Wrap-Up.


Click on the map above for a larger version of the map. Use the reload/refresh button to ensure the latest forecast map is displayed.

More information on this outlook is available from 9.00am to 5.00pm (CST) Monday to Friday by contacting the Climate and Consultancy section in the Bureau's Darwin Office: (08) 8920 3813.


Corresponding temperature outlook

August 2004 rainfall in historical perspective

June to August 2004 rainfall in historical perspective


Background Information