|NSW Seasonal Rainfall Outlook: probabilities for May to July 2005, issued 15th April 2005|
Wetter season favoured in northern and eastern NSW
There is a moderate shift in the odds towards above average rainfall for the May to July period 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 late autumn to mid-winter period, the chances of above median rainfall are between 60 and 70% in an area roughly bounded by Nowra, Cobar, Windorah, Rockhampton and the east coast (see map). So in years with ocean patterns like the current, about six or seven May to July periods out of 10 are expected to be wetter than average across much of eastern and northern NSW, with about three or four out of ten being drier.
Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During the May-July period, history shows this influence to be moderately consistent in patches over the northeast half of the State, but excluding the Moree region where the influence is only weakly consistent (see background information).
After reaching 29 in February, the Southern Oscillation Index (SOI) rebounded strongly in March to a value of 0. The approximate SOI for the 30 days ending 12th April was +6.
Low SOI values in February and subsurface warming in the central Pacific 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 17th MAY 2005