A major El Nino

MetService News Release
Tuesday, 28 Jul 2015

A major El Nino

Over the last few months, El Nino has continued to intensify. The ocean and the atmosphere have reinforced each other, helping to strengthen the climate pattern which resides in the tropical Pacific Ocean. "We have a major El Nino in play," said MetService meteorologist Georgina Griffiths.

Warmer than usual seas in the equatorial Pacific Ocean is one of the obvious signs of an El Nino - the so-called El Nino 'warm tongue'. This pool of unusually warm water upsets the normal balance of trade winds and weather in the tropics. The sea temperatures across the eastern half of the Pacific are now in excess of 2C above normal. "The warmth in the Pacific Ocean has now reached levels not seen since the 1997/98 El Nino," commented Griffiths.

So far this winter, we have already seen solid signs of El Nino in the New Zealand region. During June and July, New Zealand experienced more frequent southerly outbreaks than usual - standard El Nino winter fare for us. The southerlies have resulted in below average temperatures, overall, for the South Island in June and July and for the North Island since the middle of June. The seas around our coastline are also colder than usual,particularly off the east coast.

El Nino will likely continue into early 2016, and there is every indication that it will remain strong for the rest of 2015. El Nino traditionally peaks towards the end of the calendar year, but it does pay to remember that any effects felt here in New Zealand may not peak at the same time.

"A textbook El Nino spring (September - November) is much colder than usual,with frequent, stormy, southwesterlies across the country," noted Griffiths. "As we head towards Christmas, those winds typically tilt westerly, drying out eastern parts of both Islands."

"New Zealand farmers need to monitor this El Nino," said Griffiths. "While El Nino effects tend to diminish as you move away from the tropics, New Zealand has shown clear impacts from strong El Nino events in the past. We urge farmers to investigate what their typical El Nino response is." One way to do that is to subscribe to the free MetService Rural Outlook via the link athttp://metservice.com/rural/monthly-outlook.

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