NIWA Outlook: October-December 2014
Overview
During September 2014, borderline El Niño conditions returned in the Pacific: sea surface temperatures rose in the
western-central Pacific, sub-surface heat content increased, and the Southern Oscillation Index persisted at about -0.7.
Both atmospheric and oceanic indicators are consequently close to conventional El Niño thresholds. International
guidance indicates the development of a weak El Niño over the next three months is likely (67% chance).
During October–December 2014, mean sea level pressures are expected to be lower than normal to the north as well as over
most of the country. This pressure pattern is expected to be accompanied by generally perturbed conditions.
Sea surface temperatures around New Zealand for the coming three months are expected to be near average.
Outlook Summary
October–December temperatures are likely (35-40% chance) to be average or above average for the east of the North
Island, but are likely (40% chance) to be average or below average for the southwest and east of the South Island.
Temperatures are likely (45-50% chance) to be near average for remaining regions of New Zealand.
October–December rainfall is likely (45-50% chance) to be in the near normal range for the north and west of the North
Island, and likely (35-40% chance) to be normal or below normal in the east of the North Island. Normal or above normal
rainfall is likely (40% chance) in all South Island regions.
Soil moisture levels and river flows are most likely (40-45% chance) to be in their near normal ranges for all regions
of New Zealand.
Full document: SCO_Oct2014_Final.docx