Outlook - March to May 2010

During autumn (March-May), mean sea level pressures are likely to be above normal to the north of the country, with slightly enhanced westerly flow over New Zealand. Temperatures are expected to be near average in the North Island, but average or above average in the South Island. Rainfall is likely to be near normal in the North Island and northern South Island, normal or above normal in the western South Island, and normal or below normal in the eastern South Island.

Temperatures are expected to be near average in the North Island, but average or above average in the South Island.

Rainfall is likely to be near normal in the North Island and northern South Island, normal or above normal in the western South Island, and normal or below normal in the eastern South Island.

Below normal soil moisture levels and streamflows are likely in the northern North Island and in the east of the South Island. Near normal or below normal soil moisture levels and streamflows are likely in the rest of the North Island and the north of the South Island, and normal or above normal conditions are likely in the west and south of the South Island.

Tropical cyclone activity in the southwest Pacific is expected to be near-normal through to May. The risk of an ex-tropical cyclone passing close to New Zealand is around the long-term average. On average during moderate to strong El Niño conditions, an ex-tropical cyclone passes within 500km of New Zealand in 6 or 7 out of 10 cyclone seasons.

In this example below, the climate models suggest that below normal conditions are likely (50% chance), but, given the variable nature of the climate, the chance of normal or above normal conditions is also shown
(30% and 20% respectively).