NSW Seasonal Rainfall Outlook: probabilities for October to December 2003, issued 16th September 2003

Generally neutral odds for NSW seasonal rainfall

The Bureau's rainfall outlook for the December quarter shows that wetter conditions are favoured in the northeast of the country, including the far northwest of NSW west of about Walgett. This outlook is largely the result of higher than average temperatures in the Indian Ocean.

For the October to December period, the chances of above median rainfall are between 60 and 65% over far northwestern NSW, but over the majority of the State the chances are between 50 and 60% (see map). So with climate patterns like the current, about 5 seasons out of 10 are expected to be wetter than average over most of NSW, with about 5 out of 10 being drier.

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

Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During October to December, history shows this influence to be moderate across the southwest half of NSW, but weak or very weak across the northeast half of the State (see background information).

The tropical Indian Ocean is currently warmer than average, whilst the Pacific is showing near normal temperatures. For more detail see the El Niño Wrap-Up. The excess warmth in the Indian Ocean has had the greater influence on the overall pattern of probabilities.

August's value of the Southern Oscillation Index (SOI) was –2, five points below the July value of +3. The approximate SOI for the 30 days ending 13th September was –1.

 

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 (EST) Monday to Friday by contacting the Climate and Consultancy section in the Bureau's Sydney Office: (02) 9296 1522.
 

THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 16th OCTOBER 2003.

August 2003 rainfall in historical perspective

June to August 2003 rainfall in historical perspective

 

Background Information