“La Nina has only just ended, but there are indications that we’ll see a rapid flip to El Nino ... together, the ocean surface warming, the build‑up of heat below the surface, and the consistent signal across many climate models give us high confidence that El Nino is on the way.”
The forecast atmospheric response from the El Nino could strengthen the tendency for high-pressure systems to be anchored over the Australian continent during winter, resulting in a southwesterly flow over New Zealand, Tunster said.
“Dryness could become an issue as spring approaches, for areas that see a reduction in their normal winter rainfall such as the east of both islands, or the upper North Island.”
The Hawke’s Bay Regional Council’s climate scientist and team leader of air and land science, Dr Kathleen Kozyniak, said that on average, strong El Nino events in the region are associated with an increase in winds from the west or southwest.
“Our western ranges mostly shield the region from rainy weather arriving from the west, so El Nino events increase the likelihood we will have below-average rainfall.
“That brings a higher risk of low river flows, lower than normal groundwater levels and a higher risk of soil moisture deficits during spring and summer.”
Kozyniak said each El Nino was different, but Hawke’s Bay tends to see drier weather during spring and summer and cooler winter temperatures.
Federated Farmers’ Hawke’s Bay president Jim Galloway said the drier-than-average winter could “get tricky” as some parts of the region were low on groundwater and dams were pretty empty.
“If we don’t get them filled up over winter, it could go dry very quickly in the spring and run into issues with stock water.”
Galloway said low dam levels were easy to notice, so it should help farmers plan and explore options early in the season.
But Galloway said the drier winter would be great for “grass utilisation and growth”.
“Instead of stock pugging up and making a mess, it’ll be nice and dry underfoot, which is good for everyone, man included, because it’s a lot easier to work in the dry than the wet.”
Galloway said it wasn’t panic stations for farmers; rather, a good time to explore what options were available by talking with advisers, Beef and Lamb, mates and attending local farming events like the Hawke’s Bay Farmer of the Year Field Day at Whakamarumaru Station, Crownthorpe on May 7.
“People have good ideas – talk to other people and just keep in touch with everyone is the best option.”
Jack Riddell is a multimedia journalist with Hawke’s Bay Today and has worked in radio and media in Britain, Germany, and New Zealand.
