NIWA Seasonal Climate Outlook February-April 2015

Press Release – NIWA

Sea surface temperatures across the equatorial Pacific Ocean are borderline between neutral and weak El Nio conditions. However — as was the case over the past few months the atmospheric circulation in the Pacifc is still inconsistent with …NIWA Outlook: February–April 2015

Overview

Sea surface temperatures across the equatorial Pacific Ocean are borderline between neutral and weak El Niño conditions.

However — as was the case over the past few months – the atmospheric circulation in the Pacifc is still inconsistent with El Niño.

International guidance indicates that the probability of El Niño conditions developing over the next three months (February – April 2015) is about 60%.

During February – April 2015, higher pressures than normal are forecast over and to the southeast of the country, and slightly lower than normal pressures are likely to the north of New Zealand.

This atmospheric pressure pattern is expected to be associated with weak easterly flow anomalies.

Sea Surface Temperatures around New Zealand are forecast to be in the above normal range all around the country.

New Zealand has a slightly elevated chance of having an ex–tropical system coming within 550km of the country during the 2014 — 2015 Tropical Cyclone season.

The tropical cyclone outlook indicates this risk will be highest during the present forecast period (February – April).

Outlook Summary

February – April 2015 temperatures are most likely (45–50% chance) to be in the above normal range for all regions of New Zealand.

February – April 2015 rainfall is most likely (45–50% chance) to be in the near–normal range in the north of the North Island and the north and west of the South Island.

Rainfall totals for the season as a whole are about equally likely (35–40% chance) to be near–normal or below normal in the east of the South Island.

In the east and west of the North Island, the coming season’s rainfall is about equally likely (35–40% chance) to be near or above normal.

February – April 2015 soil moisture levels are most likely (45% chance) to be below normal in the east of the South Island and about equally likely (35–40%) to be near–normal or below normal in all regions of the North Island and the west of the South Island.

Soil moisture levels are most likely (40% chance) to be near normal in the north of the South Island.

River flows are most likely (50% chance) to be below normal in the east of the South Island and about equally likely (35–40% chance) to be near or below normal in the north and west of the North Island and the west of the South Island.

Near normal river flows are likely (40% chance) in the east of the North Island and the north of the South Island.

Full outlook: SCO_Feb2015.pdf

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