Global setting & climate outlook

Global setting and climate outlook

Pacific conditions near neutral but ENSO, signals mixed

  Difference from average global SST (click to enlarge).
Monthly SOI values (click to enlarge).

The tropical Pacific is showing some signs of a move towards La Niña, but signals are mixed, suggesting a level of uncertainty that is typical for this time of year. Pacific equatorial sea surface temperatures (SSTs) remain above normal to the west of the Date Line, but there is development of an enhanced ‘cold tongue’ in SSTs off the South American coast. There is a possibility of a La Niña event developing over the coming 3–6 months, although most models of ENSO favour near neutral conditions for the next 6–9 months.

Sea surface temperatures around New Zealand

 

New Zealand SST (click to enlarge).

Sea surface temperature differences from normal in the New Zealand region were small for March. Anomalies were slightly positive at +0.1 °C, a rise of around 0.5 °C since the start of 2007. The January to March mean anomaly was about -0.1 °C. Sea waters to the southeast are relatively cool, while the Tasman is slightly warm, at least near the surface.

Outlook for April to June 2007

 

Regional outlook (click to enlarge).

Pressures are expected to be higher than average to the east of the North Island over the coming season, with more southwesterly flows than usual over southern New Zealand. Sea surface temperatures in the New Zealand region are expected to remain near normal for the coming three months.

Air temperatures are expected to be near average in the North Island and average or below average in the South Island. Normal rainfalls are expected in most districts, but near or below normal falls are expected in the eastern South Island. Normal or above normal soil moisture levels are likely in the north of the North Island. Below normal soil moisture levels and streamflows are likely in the east of the South Island. Elsewhere, normal soil moisture and streamflows are expected.