|NSW Seasonal Rainfall Outlook: probabilities for April to June 2005, issued 18th March 2005|
Wetter season favoured in northern and eastern NSW
There is a moderate shift in the odds towards above average rainfall for the June quarter (April-June) in parts of eastern and northern NSW, the Bureau of Meteorology announced today. For the rest of the State, the chances of accumulating at least average rain for the coming three months are close to 50%.
For the April to June period, the chances of above median rainfall are between 60 and 70% in an area east of a line from Nowra to Cobar to Cunnamulla (see map). So in years with ocean patterns like the current, about six or seven June quarters out of 10 are expected to be wetter than average in these parts of northern and eastern NSW, with about three or four out of ten being drier. However, the outlook consistency (see below) is weak in some of this area so the outlook should be used with caution.
Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During the June quarter, history shows this influence to be moderately consistent along the coast and ranges from Wollongong to the Queensland border, in the northern border regions around Walgett and in the far southwest of the State near the Victorian and SA borders. Elsewhere the influence is only weakly or very weakly consistent (see background information).
After reaching +2 in January, the Southern Oscillation Index (SOI) fell strongly in February to a value of 29, the lowest for any month since February 1983 (33). The approximate SOI for the 30 days ending 15th March was 20.
Recent low SOI values have caused some speculation regarding a possible El Niño developing in 2005. While the risk has increased it is too early at this stage to predict what might happen in the Pacific, with any confidence. For routine updates and comprehensive discussion 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 ENSO 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 (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 15th APRIL 2005