Outlook - September to November 2012
Borderline El Niño conditions are present in the tropical Pacific, and a weak El Niño is likely over the spring and summer periods. However, enhanced southwesterly and westerly airflow over New Zealand that is usually associated with El Niño is not yet evident in the season forecast models. Thus, over the spring period (September-November), higher than normal pressures are expected in the south Tasman and over southern New Zealand, along with lower pressures to the north of the North Island and weaker than normal westerlies over the country. Sea temperatures around New Zealand are likely to be near normal for the season as a whole.
Spring rainfall, soil moisture and river flows are likely to be above normal or near normal in the north and east of the North Island, near normal in the west of the North Island and in Nelson-Marlborough, and near or below normal in remaining South Island regions.
September-November temperatures are likely to be near average in all regions.