Rainfall is expected to be higher than usual this summer, providing some relief to Wairarapa farmers. PHOTO/GRACE PRIOR
GRACE PRIOR
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Wairarapa is in for an unusually hot and wet summer this year, rather than the hot and dry conditions the region is used to.
Niwa meteorologist Ben Noll said Wairarapa people would experience periods of high temperature and humidity over the summer season.
Planning for a hot and humid summer was essential for farmers as these conditions would increase the chances for facial eczema in livestock, Noll said.
“Variability is the theme this year; keeping up on the weather systems is more important than ever before,” Noll said.
The average summer rainfall for Masterton is 185mm, but this was expected to be exceeded this summer, Noll said.
Changes in Wairarapa weather were mostly due to the ongoing La Nina weather event, Niwa said in its seasonal climate outlook report.
“La Nina’s signature remains prominent in the upper-oceanic heat content pattern, with well below normal temperatures in the central equatorial Pacific and continued above-average warmth in the west,” Niwa said.
“In the east, some warming was observed closer to the surface. This likely indicates a progression toward a central Pacific La Nina, as opposed to a more traditional east-based event; this could help to describe a summer season that has a mixture of drier westerlies and wetter northerlies in New Zealand,” Niwa said.
“La Nina lends to high-intensity rainfall throughout the season,” Noll said.
Temperatures are predicted to be above average across the country this summer, “forecast confidence for temperatures is high”, Niwa said,
Niwa was confident that there would be substantially warmer-than-average local sea temperatures and sub-tropical winds.
For the tropical cyclone season, which happens from November 2020 to April 2021, Niwa’s Southwest Pacific tropical cyclone outlook indicated that the risk for New Zealand was elevated.
“On average, one ex-tropical cyclone passes near the country each year. Significant rainfall, damaging winds, and coastal inundation can happen during these events,” Niwa said.
“During November, marine heatwave conditions formed in the north of the North Island, extending east and west of the region into the Pacific and the Tasman Sea.
Coastal water temperatures also warmed notably in the east of both islands and west of the South Island.
This outlook favours the continuation of hot seas, with marine heatwave conditions possibly developing in other regions,” Niwa said.
Niwa said that abnormally warm ocean temperatures “can have a profound impact on air temperatures over land and provide fuel to cyclones approaching from the north.
“The marine and fisheries sectors should keep an eye on this evolving situation, as it could be similar to what happened in late 2017-early 2018.”
Noll said overall with climate change Wairarapa was expected to get hotter and drier, but this weather event is on a different time scale than climate change. It doesn’t necessarily conform to long term trends.
The La Nina weather event was expected to peak in early 2021, bringing tropical trade winds that were expected to continue to be stronger than average over the next several months, Niwa said.
