|NSW Seasonal Rainfall Outlook: probabilities for February to April 2007, issued 23rd January 2007|
Neutral outlook for late summer to mid-autumn rainfall in NSW
The outlook for total February to April rainfall, shows a neutral pattern of odds over NSW, with no strong shifts towards either wetter or drier than normal conditions. The pattern of seasonal rainfall odds across NSW is a result of higher than average temperatures in the Pacific Ocean (because of El Niño) and also in the Indian Ocean. More influence has come from the Pacific.
The chances of exceeding the median rainfall for the February to April period, range from near 45% in the north of the State to around 60% in the far southwest border with SA and Victoria. So in years with ocean patterns like the current, about five or six February to April periods out of ten are expected to be wetter than average over NSW, with about four or five out of ten being drier.
Outlook confidence is related to how consistently the Pacific and Indian Oceans affect Australian rainfall. During the February to April period, history shows the effect to be moderately consistent in parts of southeast NSW, but across most of the State the effect is only weakly or very weakly consistent (see background information).
December was the second successive month when the Southern Oscillation Index (SOI) was only slightly negative, with a monthly value of −3 following the −1 in November. A link to 30-day SOI values is available in the ENSO Wrap-Up (see next paragraph).
The neutral SOI is one of a few indicators which show that the current Pacific El Niño pattern is beginning to weaken. 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, please see the ENSO Wrap-Up.
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|More information on this outlook is available from 9.00am to 5.00pm (EST) Monday to Friday by contacting the NSW Climate Services section in the Bureau's Sydney Office: (02) 9296 1610 or (02) 9296 1525.|
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 22nd FEBRUARY 2007