Pockets of Central Otago and Southland could reach meteorological drought by summer's end, as La Niña continues to drive dryness across the South Island. Photo / Sarah Ivey
Pockets of Central Otago and Southland could reach meteorological drought by summer's end, as La Niña continues to drive dryness across the South Island. Photo / Sarah Ivey
Areas of Otago and Southland could be in drought by summer’s end, as La Niña continues to bring its contrasting wet-and-dry flavours to the north and south.
Niwa’s five-week forecast shows pockets of those already parched regions could soon meet the threshold for meteorological drought – or that caused by a severe deficit in normal rainfall.
Widespread dryness being observed across the most of the South Island was also expected to expand to swathes of the west of the lower North Island by late February.
“This dryness has been persistent across Southland, Stewart Island, inland Otago and the West Coast, where Greymouth just had its fourth-driest December, and is tracking toward its fourth-driest January,” Niwa meteorologist Ben Noll said.
“They may be struggling with water availability, or at least getting concerned about it.”
Niwa’s latest “Hotspot Watch” reported that many parts of the upper, eastern and lower South Island received no rainfall over the past week – and that moisture-starved hotspots had developed in Banks Peninsula, much of Otago, and coastal Southland.
While parched conditions on the West Coast may be slightly eased by rainfall later this week, many other parts of the south might only receive 15mm across a week – leading soil moisture deficits to decrease “substantially” in many places.
The ocean-driven climate system that’s influenced much of the southern dryness, La Niña, was predicted to fade over autumn.
But Noll said a “lag” between the atmosphere responding to changes in the ocean could mean north to northeast winds could keep blowing into the south next season – potentially extending its bout of dryness.
In spite of those conditions, current fire danger across the South Island was mostly either moderate or low.
Niwa is forecasting dryness to expand across the South Island. Source / Niwa
Meanwhile, the picture was markedly different in the North Island.
Only parts of Manawatū, King Country and eastern Northland were currently sitting on the drier side, with most regions having received tens of millimetres more than their normal rainfall amounts.
