Three-month outlook

The outlook for February to April 2002

Recent changes in the Pacific mean an El Niño "alert" is in place, but it is too early in the year for a confident El Niño prediction to be made (see page 4). Large scale pressure patterns are likely to favour higher than usual air pressures in the north Tasman Sea, with a slightly enhanced westerly windflow over the country.

Sea surface temperatures near New Zealand should remain higher than usual through the period, except possibly to the northwest of the country, where they should remain near normal.

Temperatures are expected to be normal or above normal (i.e., middle or upper tercile) in all districts. Rainfall is expected to be normal to below normal in the north and east of the North Island, in eastern Marlborough, and in Southland, but normal elsewhere.

Soil moisture levels and river flows are expected to be near normal for the period.

A. Climate models give no strong signals about how the climate will evolve, so we assume that there is an equal chance (33%) of the climate occurring in the range of the upper, middle, or lower third (tercile) of all previously observed conditions.

B. There is a relatively strong indication by the models (60% chance of occurrence) that conditions will be below normal, but, given the variable nature of climate, the chance of normal or above-normal conditions is also shown (30% and 10% respectively).