|NT Seasonal Rainfall Outlook: probabilities for February to April 2007, issued 23rd January 2007|
Neutral outlook for end of NT wet season
Although the outlook for total February to April rainfall points to drier conditions over northern Queensland, for the NT there are no strong shifts towards either wetter or drier than normal conditions.
The pattern of seasonal rainfall odds across the NT is a result of higher than average temperatures in the Pacific Ocean (because of El Niño) and also in the Indian Ocean. The warm Pacific promotes drier than average weather, while the Indian has a weaker influence in the other direction. Hence the two signals tend to cancel each other over the Territory.
The chances of exceeding the median rainfall for the final quarter of the northern wet season, range from 55% in the far southwest corner to near 40% along the border region with far northwest Queensland. So in years with ocean patterns like the current, about five or six February to April periods out of ten are expected to be drier than average in the NT, with about four or five out of ten being wetter.
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 through the northern half of the NT, but only weakly or very weakly consistent in the south (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 (CST) Monday to Friday by contacting the Climate and Consultancy section in the Bureau's Darwin Office: (08) 8920 3813.|
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 22nd FEBRUARY 2007