|Vic Seasonal Rainfall Outlook: probabilities for October to December 2005, issued 15th September 2005|
Reduced falls for parts of southern Victoria
Seasonal rainfall odds released today by the Bureau of Meteorology, indicate an increased likelihood of below median falls over parts of southern Victoria for the December quarter (October to December).
For the October to December period, the chances of above median rainfall are between 30 and 40% in a band extending from the far southeast of South Australia to West Gippsland (see map). This includes most of the areas that have been suffering severe short-term rainfall deficiencies since the start of autumn, and a general downturn in rainfall since the mid 1990s. See the Drought Statement for more information. The chances of a wetter than average season are between 40 and 50% over the rest of the State.
So in years with ocean patterns like the current, about three or four December quarters out of ten are expected to be wetter than the median over southwest and south-central Victoria with about six or seven out of ten being drier.
Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During the December quarter, history shows this influence to be moderately consistent across much of Victoria (see background information).
The Southern Oscillation Index (SOI) fell from +1 in July to −7 in August. However, the SOI has begun to rise again with the approximate value for the 30 days ending 12th September being −1.
With all the main tropical Pacific climate indicators remaining neutral, an El Niño event developing in 2005 is not considered a realistic possibility. 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 Victorian Regional Office: (03) 9669 4949.|
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 18th OCTOBER 2005