December likely to be drier than average | Video

Odds firm for a dry December | Video

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Bureau of Meteorology says December looks likely to be drier than average across most of inland Australia.

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December is likely to be drier across most of mainland Australia, with a 70 to 80 per cent chance of below average rainfall across most of eastern Australia.

Summer (December to February) rainfall is likely to be below average across parts of eastern Australia and above average in northwest WA.

The current outlook, released by the Bureau of Meteorology last week, reflects a negative Southern Annular Mode.

Historical outlook accuracy for summer rainfall is moderate to high over most of WA, and moderate over the eastern mainland. Elsewhere, accuracy is low to very low.

The outlook also indicates that warmer-than-average days and nights are likely in the east and northern tropics while it is expected to be cooler in the far south. 

Climate influences include a neutral El Niño–Southern Oscillation and above-average ocean temperatures to Australia's northwest.

A northward shift in the usual position of the westerly winds to Australia's south—known as the Southern Annular Mode—is the dominant influence in December

It is expected to be in a negative phase in December.

When this happens in summertime, weather systems are further north than usual, meaning Australia experiences higher pressures than normal.

This is typically associated with reduced rainfall and higher temperatures.

The Pacific Ocean, though in a neutral ENSO phase, is tilting slightly towards La Niña, increasing sea surface temperatures in the western Pacific Ocean, including around northern Australia.

This may be raising the likelihood of increased rainfall over northwest WA during summer.

To view the full summer outlook including rainfall probability maps click HERE.

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