Farmers told to expect El Nino summer
El Nino is brewing in the Pacific - and some say it will bring an intensely windy and drought-filled summer.
The weather phenomenon brings a cool summer to Wellington, as winds from the west increase. Over the country, these breezes cause more rain to fall on the west coasts, while the east can get extremely dry.
In 1997 and 1998 the situation known as El Nino caused widespread droughts across the country, costing farmers hundreds of millions of dollars. Researchers at the University of Hawaii said the atmosphere now looked strikingly similar to how it did in mid-1997.
"The similarity of these conditions . . . has raised concerns that a strong El Nino event is developing for the winter of 2014 and 2015," they concluded.
The situation commonly starts to build at this time of the year, reaching a peak by the end of the year.
At home, the National Institute of Water and Atmospheric Research was also monitoring the sea surface temperatures for signs of the phenomenon.
All the measurements had now reached values close to or at the conventional El Nino thresholds, spokeswoman Susan Pepperell said. "But [these] are required to persist at these levels for at least three months to officially declare El Nino status."
Federated Farmers adverse events spokeswoman Katie Milne said an intense El Nino would have dramatic effects on farms in eastern areas such as Hawke's Bay and Canterbury.
West Coast and Southland farms would also need to prepare for extreme downpours.
But Milne warned weather predictions - while useful for farmers to prepare - were only best guesses.
"I've been telling people to refer to their own records of the last El Nino that they experienced, or if they're new to the area, talk to neighbours who might have had one and get an idea of what it means for your locality," she said.
Farmers could now begin to look at irrigation, de-stocking and boosting feed stores.
El Nino is one stage of a climate cycle affecting the Pacific Ocean. Typically, trade winds blow west across the Pacific Ocean. Warm waters build up around Australia and Indonesia, while cool water bubbles up along the coast of South America.
In an El Nino year, the trade winds drop, allowing winds to blow east across the ocean, affecting countries around the Pacific.
Its opposite - La Nina - tends to hit the northeast with rain, and was last in place in 2011-12. The last two summers, Pacific Ocean conditions were neutral.