Farmers will weather El Nino challenges

Blue Skies Weather forecaster Tony Trewinnard has held six meetings around the South Island with farmers over the last two months to discuss the impact of El Nino and what happens afterwards. His latest meeting last Thursday was with Ashburton Federated Farmers members.

Speaking from his base in Amberley, Trewinnard, who has forecast weather for the agricultural sector for 40 years, says most farmers are either curious or nervous but they all want information now so they can get on and plan.

He feels El Nino is peaking now and has two main concerns: "Firstly what will be the impacts of El Nino and secondly what will happen downstream of the El Nino peak?"

This El Nino is predicted to be among the most significant weather events in recent history, the two closest being the 1982-83 and 1997-98 summers. Trewinnard says while every El Nino is unique, this one is exhibiting a similar pattern to 2009-10: a cold spring with south-westerly airflow followed by a warming summer that will be drier and sunnier than normal.

"While in 2009-10 this didn't produce an extreme drought, parts of the country are coming into this from a prolonged period of dry weather and so are on the back foot already and this will further strain those areas."

Trewinnard says for farmers this will mean Canterbury will be dry, and the West Coast will be wetter than normal, likely to have mud rather than grass and associated issues with stock standing in muddy ground.

Meanwhile, he predicts Southland and Otago will be colder than normal with westerly airflows that will limit growth. The East Coast of the North Island, like Canterbury, Trewinnard predicting will also be dry.

"The risk to the west coast of the North Island, north of Taupo, is that sometimes in an El Nino cycle it will also be dry; some of the worst droughts in Waikato have occurred during an El Nino cycle."

However, Trewinnard says modern technology has allowed forecasters to predict this El Nino cycle at least a year out and many farmers are already prepared. Most farmers he has met are looking forward and wanting information on what will be coming next.

Trewinnard's concerns about what will happen downstream of the El Nino peak are that the data is indicating a transition to a significant La Nina pattern about this time in 2016.

"This will likely mean from the El Nino peak we will have a dry summer, a dry autumn and possibly a dry winter through to the La Nina peak."

While grain and wine producers will be happy with a dry summer and lots of sunshine, fruit growers are counting the cost of the frosts in early November and will likely have much lower yields.

He says dairy farms without irrigation will have a tough time in this period, and for those with irrigation Trewinnard predicts a high usage season.