Global setting and climate outlook

Global setting and climate outlook

El Niño-Southern Oscillation now neutral

Difference from average global SST (click to enlarge).

Monthly SOI values (click to enlarge).

The La Niña has ended, and the tropical Pacific is in a neutral state. The sea surface temperature anomaly in the NINO3 region (90–150°W) rose sharply in July to about +0.9 °C, while closer to the Date Line the surface temperature anomaly remained slightly negative. Equatorial trade winds were slightly enhanced about and west of the Date Line but were near normal elsewhere. Almost all international seasonal climate models predict ENSO neutral conditions for the next three months.

Sea surface temperatures(SST) around New Zealand

New Zealand SST (click to enlarge).

Sea surface temperature (SST) anomalies in the New Zealand region have eased but remained slightly positive for July at +0.2 °C (3-month mean +0.3 °C). Surface temperatures around New Zealand are likely to be near normal for the forecast period. SSTs across much of the Southern Hemisphere were close to normal in July.

Outlook for August to October 2008

Regional outlook (click to enlarge).

In the New Zealand region, mean sea level pressures are likely to be higher than normal to the southwest of the South Island. Westerly winds are likely to be weaker than normal over the country, but episodes of strong northerly or southerly winds are likely, as storms pass across New Zealand.

Air temperatures are likely to be average or above average in most regions, but average or below average in the eastern South Island. Rainfall is likely to be near normal in most regions, normal or below normal in the southwest of both islands. Soil moisture levels and stream flows are likely to be normal or above normalin the northern North Island and normal or below normal in the southwest North Island. In most other regions, near normal soil moisture levels and stream flows are likely, apart from normal or below normal stream flows in the southwest South Island.