By Jonathan Underhill
The El Niño weather pattern, among the three strongest since 1950, is expected to abate through summer and autumn but given its intensity, New Zealand farmers are still at risk of drought, says the National Institute of Water and Atmospheric Research.
Niwa is due to release its first Hotspot Watch report for 2016 and monthly climate report on Friday.
The last Hotspot on December 24 showed drier-than-normal soil moisture across much of the North Island and in the northern and east of the South Island but the situation has been complicated by heavy rains over the New Year.
New Zealand Meat Board data shows more livestock was killed in the first eight weeks of the season through November 28 than in the year-earlier period, suggesting some farmers are already responding to dry weather, which stifles pasture growth.
"We're expecting El Niño to weaken for the rest of the summer and by the end of the second quarter to return to more neutral conditions," said Niwa forecaster Chris Brandolino.
That concurs with the Australian Bureau of Meteorology's assessment that the weather event peaked in recent weeks and conditions would return to neutral in the second quarter, based on El Niño-Southern Oscillation measures.
Reserve Bank researchers have estimated a strong El Niño event could reduce New Zealand's gross domestic product by 0.3 percent-to-0.8 percent.
Soil moisture figures to be released this Friday will show "pretty wet soils from Coromandel, Auckland and the east of Northland, reflecting the "good dumping" from New Year's Day, Brandolino said.
But data also shows "an extreme gradient" of a very moist east coast and a much drier west in Northland.
The central and western North Island are quite dry while soil moisture levels in Hawkes Bay south to Wellington were about average but expected to decrease.
In the South Island, just less than the northern half was not too bad while south of Banks Peninsula, soil moisture is low, he said.