After an extremely soggy start to 2023, New Zealand’s north can expect a welcome shift to generally drier conditions over the next three months – courtesy of a fast-forming El Nino. Photo / NZME
After an extremely soggy start to 2023, New Zealand’s north can expect a welcome shift to generally drier conditions over the next three months – courtesy of a fast-forming El Nino. Photo / NZME
After an extremely soggy start to 2023, New Zealand’s north can expect a welcome shift to generally drier conditions over the next three months – courtesy of a fast-forming El Nino.
Experts predict an ocean-atmosphere “coupling” over coming months will finally bring New Zealand El Nino’s full flavours – marking a distinct change from a warm-and-wet La Nina regime that’s long plighted the north.
Niwa’s just-issued outlook for the August to October period picked below-normal rainfall for the north of the North Island, while the west of the North Island and east of the South Island are expected to have near-normal levels.
In the east of the North Island, the chance of near-normal or below-normal rainfall is about equal, while the west and north of the South Island may see an equal likelihood of near-normal or above-normal levels.
“I’d need to see exactly when we last had an outlook with below-normal rainfall for the northern North Island, but it’s likely been a couple of years at least,” Niwa meteorologist Ben Noll said.
“This should be a welcome change for areas at the top of the country; whether that’s people wanting to get outside and enjoy more tranquil, drier conditions, or farmers hoping for a decrease in their paddocks’ soil moisture levels.”
As at June, a list of locations across the upper North – including Kaikohe, Whangārei, Warkworth, Albany, Māngere, Tauranga, Gisborne and Napier – had already been drenched with an average year’s worth of rainfall.
“In the east coast of the North Island, we can see the odds for rainfall are split down the middle – and the signal for lower amounts isn’t quite as strong as it is for the top of the country, but this should still be positive news for those areas.”
At the same time, however, he said there was potential for several heavy rainfall events along the East Coast next month.
“As early as next Wednesday, we’re expecting a southerly change that’s likely to drag some rain across that region, while in mid-August, we see another opportunity for some moisture to come into the east of the North Island,” he said.
“However, as we go later into August, and into September and October, I do think a growing trend toward more westerlies is going to be a friend for these eastern areas.”
The outlook indicates above-normal pressure to northwest of the country, and below normal to the south, leading to an increase in southwesterly winds during the season – a classic set-up of El Nino.
Those winds are also projected to be stronger than usual, particularly affecting the South Island and lower North Island.
Source / Niwa
Temperature-wise, Niwa expects varying trends across New Zealand, with northern regions equally likely to feel near or above-average conditions.
In all other regions, temperatures are more likely to be above average, as westerly winds carry warm air from Australia into the region at times.
The outlook comes as New Zealand’s coastal seas are still remarkably warm for mid-winter – sea surface temperatures ranged from 0.3C to 1.8C over July – which is helping to take some of the bite out of cold snaps.
That buffering effect may continue, as Niwa reports warmer-than-average seas could potentially reduce the intensity of the typical late winter and spring cold, southerly air masses.
