When Weather Matters - Mixed rainfall outlook for early 2006

In line with recent rainfall patterns, there are increased chances of a wetter than average March quarter (January to March) over parts of southeast Queensland, northern New South Wales and southwest WA (see map), the Bureau of Meteorology announced today. In contrast, some areas in the NT and northern WA have an increased risk of below average falls. However, the chances of ac*****ulating at least median rain during the coming three months are close to 50% across much of the country.

For the January to March period, the chances of above median rainfall are between 60 and 70% over southwest WA, parts of northeast and northern New South Wales together with adjacent areas in southern Queensland (see map).

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 these parts of Australia, with about three or four out of ten being drier. However, this is a seasonally dry time of year in southwest WA and high totals are relatively rare.

Some small areas in the north of the NT and WA have chances of exceeding the January to March median that are a little below 40%, indicating an increased risk of drier than average conditions. However, the outlook skill is low across some of this region 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 March quarter, history shows the effect to be moderately consistent through eastern parts of NSW and Queensland, large parts of the NT and over much of southern and western WA. Elsewhere the effect is only weakly or very weakly consistent.

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.