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It’s official – La Niña is back. What this means for NZ:

The long awaited La Niña, which was first predicted by the Climate Prediction Center (CPC) back in April, has finally arrived in the Pacific Ocean, NOAA announced late last week — and it’s expected to stick around through the upcoming summer.

La Niña conditions, which are characterized by below-normal sea surface temperatures in the tropical Pacific, were observed during October and have persisted into November — prompting the CPC to raise the ENSO Alert System from a La Niña Watch to a La Niña Advisory.
La Niña, much like its warmer counterpart, El Nino, have far reaching global impacts extending beyond the Pacific Ocean.
Fortunately, the current La Niña is weak and is expected to stay that way through [summer]. This should keep the impact from being as severe as what was seen globally with 2015’s record-setting El Niño, which saw deadly drought in Asia and helped make it the hottest year on record.
La Niña generally tends to lower global temperatures as it cools the surface of the tropical Pacific Ocean
It will be interesting to see if this La Niña can slow down the rapidly rising global temperatures and prevent 2016 from outpacing 2015 and becoming the third consecutive hottest year for the planet.

– By Brandon Miller, CNN with CNN Meteorologist Judson Jones contributing.

What does La Nina mean for New Zealand?
Many people, especially in the North Island and upper South Island have been saying it’s felt a bit like La Nina for the past two months, so a weak La Nina coming in across the Pacific is no real surprise. (as it’s been wetter and cloudier than average in many of these areas).
It means we just have to look at what is currently happening to get an idea as to what a La Nina summer in New Zealand will look like.  In bullet points here is what New Zealanders can (very generally) expect:
  • Slight warmer sea temperatures
  • Cloudier weather, especially coastal areas
  • Higher risk for afternoon showers, especially inland
  • Wetter than average for many North Island and some western and northern South Island areas.
  • An uptick in easterlies
  • A slight increase in an ex-cyclone passing by New Zealand or directly impacting New Zealand
  • Generally warm & possibly more humid

Basically many areas have already been experiencing similar conditions.  For drought affected Canterbury La Nina can drive in more easterlies (good for getting moisture in to your area) and also an increase in spillover rain from West Coast events.  At this stage nothing to indicate a major turn around in the weather pattern over the South Island. Remember this La Nina is considered to be weak.


Image / The red/pink shading at sea shows how La Nina’s warmer than average sea surface temperatures can be seen in western parts of the ocean (like around New Zealand and Australia) while up at the tropics towards the Americas you can see blue shading which indicates it’s cooler/drier in the east of Pacific Ocean. This is the complete opposite to El Nino and has American forecasters very worried about big droughts across the US, while Australian forecasters are worried about flooding and more heat.  Image via Wunderground.

 – with CNN and Wunderground


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