North Island to be hammered by heavy rain and gales this weekend

A “tropical moisture plume” is headed for New Zealand this weekend bringing with it heavy rain and gale-force winds.

The relatively fine weather predicted for the remainder of the work week will be short-lived with meteorologists predicting a front from the tropics to bring heavy rain in the South Island from Saturday with the top of the country copping the worst of the weather on Sunday.

NIWA is predicting a “tropical moisture plume” will hit the North Island this weekend with a chance of heavy rain, especially on Sunday in the North Island.

💧 A tropical moisture plume (🟣) has its sights set on the North Island this weekend...

Since it's coming from the tropics, there's a chance for heavy rain, especially on Sunday.

It looks relatively short-lived due to incoming high pressure, but keep an eye on the forecast! pic.twitter.com/edhuhOikZ2

— NIWA Weather (@NiwaWeather) August 16, 2023

MetService already has heavy rain watches in place for the west coast of the South Island on Saturday but agreed the worst of the weather will hit the North Island on Sunday, meteorologist Andrew James said.

James said severe weather watches for the central North Island were likely to be added tomorrow with the possibility some would be upgraded to warnings.

“Rain gets going along the South Island’s west coast during Saturday morning, then into the afternoon the system moves onto the North Island,” he said.

“Wherever you are, Saturday’s best weather is going to be early in the day.”

Severe Weather Watches for this weekend on the South Island/Te Waipounamu

🌧 Tasman about and west of Motueka. Noon to 10pm Sat.
🌧 Ranges of Westland, south of Otira. 10am to 8pm Sat.
💨 Fiordland, about the Fiords. 8am to 5pm Sat.

Full details https://t.co/qHyE5zzql5 pic.twitter.com/bA9ZjctPLJ

— MetService (@MetService) August 16, 2023

The tropical front is expected to like just to the West of the country by midnight Saturday bringing rain and strong to gale-force winds to exposed places.

On Sunday, the full force of the storm is expected to hit the top of the country - from Northland down to North Taranaki, the central high country and the Bay of Plenty - bringing with it heavy rain and severe northeasterly gales.

Nelson/Tasman and northern Marlborough are also expected to be in the firing line on Sunday with heavy rain also forecast there.

According to MetService, the last of the foul weather could hit Gisborne and northern Hawke’s Bay on Monday.

Both NIWA and MetService expect the latest storm to be short-lived because of a ridge of high pressure expected to hit the country early next week.

The latest deluge will be unwelcome news for North Islanders who had more than a year’s worth of rain in the first six months of 2023.

“Those living in Northland, Auckland, the Coromandel Peninsula, Gisborne, and Hawke’s Bay have dealt with a constant barrage of sub-tropical lows, atmospheric rivers, and ex-tropical cyclones, which caused copious amounts of rainfall. It has been quite relentless,” NIWA meteorologist Ben Noll said when he announced the record-breaking rainfall amounts last month.

Kaikohe, Whangārei, Warkworth, Leigh, Whangaparāoa, Albany/North Shore, Māngere, Tauranga, Gisborne, Tūtira and Napier all recorded more rain in the first six months of the year than they would normally get in a year.

NIWA said the lingering influence of La Niña contributed to an air pressure pattern that brought more sub-tropical, northeasterly winds, atmospheric rivers, and increased the risk for ex-tropical cyclones.