|Vic Seasonal Rainfall Outlook: probabilities for January to March 2007, issued 20th December 2006|
Increased rainfall in March quarter for southwest Victoria
The latest seasonal rainfall outlook issued by the Bureau of Meteorology shows a moderate shift in the odds towards above-normal March quarter (January to March) rainfall for southwest Victoria. However, the confidence in the outlooks at this time of year is rather low, so this outlook should be used with caution.
The pattern of seasonal rainfall odds across Victoria is mostly a result of higher than average temperatures in the Pacific Ocean (because of El Niño).
The chances of exceeding the median rainfall for the January to March period, are between 60 and 65% over southwest Victoria and a narrow coastal strip in southeast SA. Over the rest, and majority, of the State, the chances are between 45 and 60% for a wetter than normal March quarter. So in years with ocean patterns like the current, about six or seven March quarters out of ten are expected to be wetter than average over this part of the country, with about three or four out of ten being drier.
Outlook confidence is related to how consistently the Pacific and Indian Oceans affect Australian rainfall. During the March quarter, history shows the effect to be only weakly or very weakly consistent in Victoria, apart from a small area on the far west coast where the effect is moderate (see background information).
The Southern Oscillation Index (SOI), negative for the seventh straight month as a result of the El Niño, rose from −15 in October to −1 in November. The approximate SOI for the 30 days ending 17th December was −4.
The current Pacific El Niño pattern, of which the low SOI is but one indicator, is expected to persist for most of the summer. 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 Climate and Consultancy section in the Bureau's Victorian Regional Office: (03) 9669 4949.|
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 23rd JANUARY 2007