Summary for New Zealand

NOAA El Niño Advisory: There is a greater than 90% chance that El Niño will continue through Southern Hemisphere summer 2015-16, and around an 85% chance it will last into early fall 2016.

During July, sea surface temperatures (SST) anomalies were near +1.0oC in the central equatorial Pacific Ocean, and in excess of +2.0oC across the eastern Pacific. SST anomalies increased in the Niño-3 and Niño-3.4 regions, while the Niño-4 and Niño-1+2 indices decreased slightly during the month. Positive subsurface temperature anomalies strengthened in the central and east-central equatorial Pacific during the month, in association with the eastward movement of a downwelling oceanic Kelvin wave. The atmosphere remained coupled to the oceanic warming, with significant low-level westerly wind anomalies continuing from the western to east-central equatorial Pacific, along with anomalous upper-level easterly winds. Also, the traditional and equatorial Southern Oscillation Index (SOI) were both negative, consistent with enhanced convection over the central and eastern equatorial Pacific and suppressed convection over Indonesia. Collectively, these atmospheric and oceanic features reflect a significant and strengthening El Niño.

All models surveyed predict El Niño to continue into the Southern Hemisphere autumn 2016, and all multi-model averages predict a strong event at its peak in late spring/early summer (3-month values of the Niño-3.4 index of +1.5oC or greater. At this time, the forecaster consensus unanimously favours a strong El Niño, with peak 3-month SST departures in the Niño 3.4 region potentially near or exceeding +2.0oC. Overall, there is a greater than 90% chance that El Niño will continue through Southern Hemisphere summer 2015-16, and around an 85% chance it will last into early fall 2016.

Northland

Temperature

October

Near normal over the entire region.

November

Near normal over the entire region.

Precipitation

October

Near normal across the entire region except the far north that should be slightly drier than normal.

November

Slightly drier to near normal across the region.

Auckland

Temperature

October

Slightly cooler (up to 0.5 degree C) over the entire region.

November

Near normal over the entire region.

Precipitation

October

Near normal throughout the region.

November

Near normal throughout the region.

Waikato

Temperature

October

The entire region should be up to 0.5 degrees C cooler than normal.

November

The entire region should be near normal.

Precipitation

October

Slightly drier than normal over most of the region except the northernmost part that should be near normal.

November

The entire region should be near normal to slightly drier in the eastern and southern part of the region.

Bay of Plenty

Temperature

October

The entire region should be up to 0.5 degrees C cooler than normal.

November

The entire region should be near normal.

Precipitation

October

The entire region should be slightly drier than normal.

November

The entire region should be slightly drier than normal to near normal in the east.

Gisborne

Temperature

October

The entire region should be up to 0.5 degrees C cooler than normal.

November

The entire region should be near normal.

Precipitation

October

The entire region should be near normal to slightly drier than normal.

November

The entire region should be near normal to slightly drier than normal.

Hawke’s Bay

Temperature

October

Much of the region could be 0.5 degrees C cooler than normal.

November

Much of the region should be near normal.

Precipitation

October

Much of the region should be normal to slightly drier than normal.

November

Much of the region should be slightly to moderately drier than normal.

Taranaki

Temperature

October

The entire region should be up to 0.5 degrees C cooler than normal.

November

The entire region should be near normal.

Precipitation

October

The entire region should be slightly drier than normal.

November

The entire region should be near normal to slightly drier than normal.

Manawatu-Wanganui

Temperature

October

The entire region should be between 0.5 and 1.0 degrees C cooler than normal.

November

The entire region should be near normal.

Precipitation

October

Much of the region should be slightly drier than normal.

November

Much of the region should be near normal.

Wellington

Temperature

October

The entire region could be up to 0.5 to 1.0 degrees C cooler than normal.

November

The entire region should be near normal to up to 0.5 degrees C cooler than normal.

Precipitation

October

The entire region should be near normal to slightly drier than normal.

November

The entire region should be near normal.

Tasman

Temperature

October

The entire region should be slightly cooler than normal except the far south should be slightly warmer than normal.

November

The entire region should be near normal except the far south should be slightly warmer than normal.

Precipitation

October

The entire region should be slightly to moderately drier than normal.

November

Most of the region should be slightly to moderately drier than normal.

Nelson

Temperature

October

The area should be slightly cooler than normal.

November

The area should be near normal.

Precipitation

October

The area should be near slightly to moderately drier than normal.

November

The area should be moderately drier than normal.

Marlborough

Temperature

October

The northern half of region could be up to 1.0 degrees C cooler than normal while the southern half could be up to 1.0 C warmer than normal.

November

The northern half of region should be near normal while the southern half could be up to 1.0 C warmer than normal.

Precipitation

October

Nearly the entire region should be slightly to moderately drier than normal.

November

Nearly the entire region could be slightly to moderately drier than normal.

West Coast

Temperature

October

Nearly the entire region could be up to 0.5 degrees C cooler than normal except the far north and alpine areas which could be slightly to moderately warmer than normal.

November

Nearly the entire region should be near normal to slightly cooler than normal.

Precipitation

October

The entire region should be slightly drier than normal.

November

The entire region should be near normal.

Canterbury

Temperature

October

Much of the eastern half of the region should be slightly cooler than normal to near normal and slightly to moderately warmer than normal in the alpine areas.

November

Much of the region should be near normal to slightly warmer than normal in the Alps.

Precipitation

October

The region should be slightly to moderately drier than normal.

November

The region should be near normal to slightly drier than normal.

Otago

Temperature

September

Much of the region should be near normal to slightly cooler than normal.

October

Much of the region should be near normal to slightly warmer than normal.

November

Much of the region should be near normal to slightly warmer than normal.

Precipitation

October

Much of the western half of the region should be slightly to moderately drier than normal and the eastern half of the region near normal.

November

Much of the region should be near normal to slightly wetter in the easternmost portions.

Southland

Temperature

October

Much of the region should be normal except for Fiordland that could be moderately cooler than normal.

November

Much of the region should be near normal except for Fiordland that could be slightly cooler than normal.

Precipitation

October

Much of the eastern half of the region should be near normal.

November

Much of the region should be near normal to slightly wetter in the south.

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