Warning of heavy rain spreads as remnants of Cyclone Debbie take aim
A rapidly rising river has forced the evacuation of a Taranaki school, as a deepening low brings heavy rain to almost all the North Island and parts of the South Island.
Ngamatapouri School in the South Taranaki District has been evacuated and closed, after the rapidly rising Waitotara River caused the closure of Waitotara Valley Rd.
MetService has issued severe weather warnings for heavy rain covering Northland, Auckland, Waikato, Waitomo, Coromandel Peninsula, Bay of Plenty, Taranaki, the Whanganui District, the Tararua Ranges, Gisborne, Hawke's Bay, Wairarapa, Taumarunui, Taupo and Taihape, as well as the Kaikoura Coast in the South Island.
Southeast gales gusting to 120kmh are also expected for a time on Wednesday in Horowhenua, Kapiti Coast, Nelson and Buller. Severe gales are also possible in Taranaki and Whanganui on Tuesday evening and in Auckland from Wednesday afternoon.
* Live: Cyclone Debbie remnants hit NZ
* Another wet week for most of North Island
* Severe thunderstorm risk for upper North Island
* Debbie's wrath of wet weather set to saturate Taranaki
* Insurers hit with 2500 Cyclone Debbie claims, brace for more
Rainfall totals could exceed 200mm in some areas, with downpours during thunderstorms of 25 to 35mm an hour or possibly more, MetService said.
Up to 350mm of rain could accumulate in the Bay of Plenty and on Mt Taranaki. Peak rainfall intensities could reach 45mm an hour in Northland, Auckland, Waikato, Waitomo, Coromandel Peninsula and Bay of Plenty.
Manawatu, Horowhenua, Kapiti Coast, Wellington, Marlborough and Nelson are also expected to get heavy falls at times throughout the next few days.
"This is a significant amount of rain and people are advised to watch out for rapidly rising rivers and streams, flooding and slips," MetService said.
High winds were picked to hit Horowhenua, the Kapiti Coast, Buller and Nelson from Wednesday morning, gusting up to 120kmh.
The low over the Tasman Sea was directing a moist northerly flow onto the North Island and a slow moving trough was expected to lie over the central North Island, MetService said.
The low was forecast to cross central New Zealand early Thursday, and both it and the trough would move away to the east and southeast.
Remember to drive to the conditions. Adjust your speed, increase your following distance & keep an eye out for surface flooding on the road. pic.twitter.com/UXWHQ7Ie4A— Taranaki CD (@TaranakiCD) April 3, 2017
Hawke's Bay Civil Defence said they were expecting to see the most rain around Central Hawke's Bay, Nuhaka and Mahia, where there was likely to be localised surface flooding.
Officials also warned rivers and streams could rise quickly and it was possible there would be some slips, roading and power issues.
Slips had cut off two roads in North Taranaki - Okoki Road and Piko Road - both inland from Urenui, and the New Plymouth District Council had sent contractors in to clear the debris.
Rain, rain, unfortunately it's not going away. While we keep an eye on river levels, please keep an eye on conditions in you immediate area.— Horizons RC (@HorizonsRC) April 3, 2017
SLOW LOW AHEAD
The rain was linked to a low in the north Tasman Sea, on a southwest course towards the North Island.
While the low had not arrived yet, associated fronts bringing rain were extending across the North Island.
The movement of the low across the country would be gradual, MetService duty forecaster Raveen Das said.
"It's not a quick hit, it's a gradual process - a lot of rain is expected to fall over most parts of the North Island and upper South Island."
"It's a significant low, bringing a whole lot of moisture from the subtropics."
As the remains of Cyclone Debbie had moved offshore near Brisbane they had become caught up with a mid-latitude trough.
"That trough is helping bring all the moisture associated with Debbie down towards us.
"Along the trough a number of lows are developing. One of those lows is becoming a deep system. Today that's going to roll onto the country."
DAYS OF HEAVY RAIN
Heavy downpours started on Monday night in Taranaki and Whanganui.
Heavy rain in Taranaki was picked to last until Wednesday, with between 250 - 400mm falling around Mt Taranaki and 150 to 200mm elsewhere, MetService said.
Rainfall was forecast to hit peak intensities 20 - 30mm per hour from Tuesday evening to early Wednesday, the agency said.
Taranaki Civil Defence Emergency Management Group duty officer Shane Brigg is telling the public to prepare for the stormy weather, as well as the floods and slips it was expected to bring.
Manawatu, Whanganui and the Tararua Ranges are expected to be hit with Debbie's force during the coming days.
The first of the heavy rain touched down in Manawatu on Monday night. It could last through to Thursday.
MetService forecaster Cameron Coutts said the rainfall would not be severe for Palmerston North, but the area was in for a significant downpour.
"We are talking heavy falls until at least Wednesday," he said.
Up to 250mm was expected to fall in the Tararua Ranges during a 30-hour period.
Coutts said low-lying parts of Manawatu could also expect up to 150mm before the low moved on.
Whanganui rain was expected to be heavy on Tuesday, turning to showers during Wednesday.
The region was in for 250mm in 33 hours to midday on Wednesday.
Horizons Regional Council said hydrology and emergency management staff would be keeping an eye on river levels across the regions.
HEAVY RAIN WARNING - TARARUA RANGES - From 6am Tuesday to midday Wednesday, 200 to 250mm of rain may accumulate. Peak intensities 20-30mm/hr— WREMO (@WREMOinfo) April 3, 2017
HEAVY RAIN WARNING - WAIRARAPA (away from the Tararua ranges) - From midnight Monday to noon Wednesday expect 120-160mm. 10 to 20mm/hr.— WREMO (@WREMOinfo) April 3, 2017
"This is a significant amount of rain for these areas and people are advised to watch out for rapidly rising rivers and streams, and possible surface flooding and slips," Coutts said.
After Thursday, a ridge was expected to arrive, which would clear the bad weather away.
Wellington was set for a deluge of double its usual rainfall for April over 48 hours with rain forecast from Monday through to Wednesday.
To add to the capital's bad weather woes, southeasterlies were expected to rise to gale strength in exposed places on Tuesday, when a high of just 13 degrees Celsius was expected.
SEVERE THUNDERSTORM RISK IN NORTH
MetService warned of a "moderate risk" of severe thunderstorms from Northland, down through Auckland to northern Waikato and across to the Coromandel Peninsula and western Bay of Plenty.
The main risk areas were likely to be about Northland and western parts of Auckland on Tuesday afternoon and evening, the agency said.
The storms could be sparked by slow-moving rainbands in the areas, and these could bring torrential falls even if the thunderstorms didn't eventuate.
DRIVERS URGED TO TAKE CARE
The NZ Transport Agency was advising people to drive to the conditions and check weather reports.
"When it is raining heavily, it is important that drivers watch their speeds, take care not to follow too closely, and be really careful when taking corners," Mark Owen, Regional Performance Manager, NZ Transport Agency said.
"Storm conditions such as wind gusts can also affect high-side vehicles, motorcyclists, and cyclists. Road users should also look out for surface flooding, and debris on the road.
"Our contractors will be monitoring road and weather conditions so they can quickly respond to any weather-related road effects. As conditions can change rapidly, we advise people to check the latest weather and road updates before they get on the road," Owen said.