Photos of 2007's wild weatherKEY POINTS:
A La Nina weather pattern for New Zealand this year could cause problems for farmers in the South Island and parts of the North Island.
Niwa's principal scientist, Dr Jim Salinger, said yesterday that the weather until March could bring trouble for farming, and undermine economic growth.
Dr Salinger said that a moderate to strong La Nina, which appeared last year, was now well in progress.
Last month had shown signs of a classic La Nina, with warm and cloudy weather in the north and a sunny south.
La Nina usually brought dry conditions to the west of the North Island and much of the South Island.
Floods were likely in the north and east of New Zealand, he said.
La Nina was expected to continue until about the end of April, going into autumn, Dr Salinger said.
He said the 2008 outlook was for a warmer start to the year, with much drier weather than usual in many South Island areas.
"The areas to watch for are the eastern areas of the South Island in particular."
Dr Salinger noted that the 1998/99 La Nina caused drought throughout the South Island, and had proven very costly to the economy.
Dr Salinger said pasture relying on rainfall rather than irrigation would be vulnerable and low rainfall could affect hydro-electricity supplies.
La Nina would bring wetter weather to the upper North Island where farmers should watch out for facial eczema and diseases related to warmer, more moist conditions.
Federated Farmers president Charlie Pedersen said the phenomenon had been well-flagged, and farmers were prepared for it.
"Most farmers will know what a La Nina is going to mean for them. They'll think back to the last time they had a La Nina, and they will plan accordingly."
Each would react according to his or her own situation and region.
Cropping farmers may alter their sowing dates, and livestock farmers will ensure they have enough feed supplement on hand.
Sheep and beef farmers in trading stock situations would trade out their animals as quickly as possible, rather than taking them to higher weights, to ensure there was enough feed to go around.
