|WA Seasonal Rainfall Outlook: probabilities for January to March 2006, issued 19th December 2005|
Above average falls favoured in southwest WA for early 2006
In line with recent rainfall patterns, there are increased chances of a wetter than average March quarter (January to March) over southwest WA (see map), the Bureau of Meteorology announced today. However, this is a seasonally dry time of year in southwest WA and high totals are relatively rare.
For the January to March period, the chances of above median rainfall are between 60 and 70% southwest of a line from Geraldton to Balladonia (see map). Across the rest of WA, the chances of accumulating at least median rain during the coming three months are mainly close to 50%.
So in years with ocean patterns similar to the present, about six or seven March quarters out of ten are expected to be wetter than the median over southwest WA, with about three or four out of ten being drier.
A small area in the far northeast of WA has chances of exceeding the January to March median that are a little below 40%, indicating an increased risk of drier than average conditions.
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 moderately consistent southwest of a line from Exmouth to Eucla, and in parts of far eastern WA. Elsewhere the effect is only weakly consistent (see background information).
After rising steadily between August and October, the Southern Oscillation Index (SOI) fell during November to a value of −3. The approximate SOI for the 30 days ending 14th December was −5.
For routine updates 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 (WST) Monday to Friday by contacting the Climate and Consultancy section in the Bureau's Perth Office: (08) 9263 2222.|
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 24th JANUARY 2006