|Tas Seasonal Rainfall Outlook: probabilities for February to April 2007, issued 23rd January 2007|
Increased late summer to mid-autumn rains in northern Tasmania
The outlook for total February to April rainfall, shows a moderate shift in the odds towards above average falls in parts of northern Tasmania. The pattern of seasonal rainfall odds across Tasmania is mainly a result of higher than average temperatures in the Pacific Ocean (because of El Niño).
The chances of exceeding the median rainfall for the February to April period, are generally around 55% in Tasmania, increasing to a little above 60% near and to the north of Launceston. 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 in Tasmania, with about four or five out of ten being drier. However, the outlook system has low skill at this time of the year, so this outlook should be used with caution.
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 only weakly consistent over Tasmania (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 Climate and Consultancy section in the Bureau's Hobart Office: (03) 6221 2043.|
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 22nd FEBRUARY 2007