Outlook - February to April 2014

Atmospheric indicators of ENSO continue at neutral levels.

International guidance indicates that the tropical Pacific Ocean is very likely to remain neutral over the next three months (February-April). Near normal mean sea level pressures are expected over the New Zealand, with lower pressures than usual to the north of the country and higher pressures than usual well to the east. This circulation pattern is expected to be associated with weak anomalous south-westerly flows over the South Island and easterly flows over the North Island. 

February-April rainfall is forecast to be normal or above normal in the north of the North Island, normal or below normal in the north and west of the South Island, and near normal for all remaining regions. 

February-April temperatures are likely to be average or above average for all North Island regions, average or below average in the west of the South Island, and average in other South Island regions.

Soil moisture levels are likely to be normal for all regions except the east of the South Island where normal or below normal soil moisture levels are expected. River flows are likely to be normal or below normal in the north and west of the South Island, and near normal for all remaining regions.

For the tropical cyclone season (November – April), the risk of an Ex-Tropical Cyclone (ETC) approaching New Zealand is expected to be close to normal. Based on the long-term record, ETCs come within 550km of New Zealand for 9 out of every 10 years. However, the most likely period is during February-April, so further events (following on from ex-tropical cyclone June in January) cannot be ruled out. For ENSO-neutral years (the current situation), any ETCs approaching the North Island are twice as likely to pass to the east of Auckland as to the west of the city.