Global setting and climate outlook

Global setting and climate outlook

La Niña weakening

Difference from average global SST (click to enlarge).

Monthly SOI values (click to enlarge).

La Niña conditions have continued to weaken in the equatorial Pacific, although some remnants of La Niña persist east of the Date Line. Sea surface temperature anomalies in the eastern equatorial Pacific increased during June to +0.5 °C, which is a continuation of the progressive warming from –1.5 °C in February 2008. The SOI was +0.4, with a 3-month mean of +0.1. The near-equatorial trade winds are slightly enhanced in the central equatorial Pacific.

Sea surface  temperatures(SST) around New Zealand

New Zealand SST (click to enlarge).

Sea surface temperature (SST) anomalies in the New Zealand region remained above normal, as part of the ‘warm horseshoe’ associated with La Niña in the southern extra-tropics. The June SST anomaly in the New Zealand box was +0.4 °C (with a three-month average of +0.5 °C). Sea surface temperatures around New Zealand are expected to remain above normal until September.

Outlook for July to September 2008

Regional outlook (click to enlarge).

In the New Zealand region, mean sea level pressures are expected to be higher than normal to the south of the South Island, and lower than normal to the northwest of New Zealand, with more winds from the northeast than normal over the country.

Air temperatures are likely to be above average in the North Island, and average or above over the South Island. Rainfall is expected to be near normal in all regions. Normal or below normal soil moisture levels are likely on the South Island east coast, and normal moisture levels elsewhere. Normal or below normal stream flows are likely in the north and east of both islands. In the west and south of both islands, normal stream flows are likely.