NIWA: Seasonal Climate Outlook

NIWA National Climate centre
1 March 2011

Seasonal Climate Outlook:
March – May 2011
A mild autumn with La Niña easing

A strong La Niña event continues in the tropical Pacific, but is showing signs of easing, says the NIWA National Climate Centre. Neutral conditions are likely in the tropical Pacific by winter.

Autumn (March to May) temperatures are very likely to be above average in all North Island regions, and are likely to be above average in all South Island regions.

Seasonal rainfall is likely to be above normal in the northern North Island, normal or above normal in the remainder of the North Island and the northern South Island, and near normal elsewhere. Soil moisture levels and river flows are likely to be above normal in the North Island and the north of the South Island, and are likely to be near normal in the rest of the South Island.

The seasonal outlook states that mean sea level pressures are likely to be below normal to the north of New Zealand and above normal to the east and south of the country, with weaker westerlies across New Zealand.

Tropical cyclone activity is likely to be near- or above-normal for the rest of this cyclone season (through to May).

Overall Picture

Temperature:
On average for autumn, temperatures are very likely to be above average in all North Island regions, and are likely to be above average in all South Island regions. Sea surface temperatures are presently above normal especially west of New Zealand and north of the North Island, and are expected to remain above normal for the time of year through autumn.

Rainfall, soil moisture, and river flows:
The National Climate Centre says that seasonal rainfall is likely to be above normal in the northern North Island, normal or above normal in the remainder of the North Island and the northern South Island, and near normal elsewhere. Soil moisture levels and river flows are likely to be above normal in the North Island and the north of the South Island, and are likely to be near normal in the rest of the South Island.

ENDS

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