Thunderstorms have mostly eased in the northern parts of Auckland this evening - but the risk of a deluge continues for a few more hours, Weather Watch says.
It comes as the National Institute for Water and Atmospheric Research (Niwa) reported much of the North Island saw up to four times the monthly average of rainfall throughout February.
Torrential rain was expected in the north when a severe thunderstorm warning was issued about 4pm, while other parts of Tāmaki Makaurau escaped the rain and basked in late afternoon sun.
🚨⛈️5:45pm - #Thunderstorms have now mostly eased in #Auckland & the biggest downpours are shrinking too - but the risk continues for a few more hours. Downpours easing (more slowly) in the rural north - flooding risk continues there.
Lightning storms had shifted north and were sitting near Whangārei, but a risk of flooding remained about rural north Auckland.
MetService issued a severe thunderstorm alert for Northland at 5.30pm - with thunderstorms expected to hit Maungatapere and Kamo about 6pm and Hikurangi and Kamo again at 6.30pm.
MetService weather radars detected thunderstorms in Northland near Maungaturoto, Kaiwaka, the Brynderwyns; and in Auckland near Warkworth, Kaipara Flats, Ahuroa, Wellsford, Te Arai and Puhoi.
The severe weather in Auckland came as a new cyclone threat loomed and States of Emergencies around the country from Cyclone Gabrielle were extended by another seven days.
Northland, Auckland, Waikato, Tairāwhiti, Waikato, Hawke’s Bays and Tararua District are all included in the extension - Bay of Plenty was not.
Bay of Plenty was able to manage its recovery within its “business as usual” council operations, Minister for Emergency Management Kieran McAnulty said.
Line of very heavy rain across Northland and north Auckland. Look for the areas of red on the radar.
A Severe Thunderstorm Warning covers part of this area. Remember, when thunder roars, head indoors.
“The impact of Cyclone Gabrielle continues to be deeply felt by many communities in the North Island,” McAnulty said.
“The states of national emergency are being regularly reviewed and I anticipate that some areas still covered by the declaration will transition to recovery before 7 March.
“Thousands of people are still unable to return to their homes due to flood damage, and tragically eleven people are known to have lost their lives”, McAnulty said.
MetService issued an urgent thunderstorm alert for Auckland north of the Harbour Bridge with the risk of heavy rain and hail which could cause flash flooding and damage.
Surface flooding has already been reported in Whangaparāoa, with a whole street submerged by water.
Severe thunderstorms have been detected on weather radars tracking east, and MetService earlier expected the storms to lie near Auckland, Inner Hauraki Gulf, and Whangaparaoa at 3.15pm.
Image 1 of 2: Aucklanders are being warned to take shelter before a potentially damaging line of thunderstorms barrels over the city. Photo / ClydeServices
Niwa said this morning the latest modelling shows the storm missing New Zealand.
Niwa meteorologist Ben Noll told the Herald that ensemble forecasting involves running multiple instances of a forecast model, or “members” repeatedly to see if a pattern emerges.
By assessing the different scenarios, meteorologists can understand whether the different members agree or disagree with one another - and as weather systems draw closer, a consensus will too.
“There are inherent uncertainties in forecasting and over time those can compound.
“Niwa runs an ensemble system with 18 different members, you can understand if they’re vastly different or similar - for example, if we have 18 members in agreement, then the forecaster confidence is high but if they disagree we can understand how they diverge and communicate those different possible forecast scenarios.”
He said given the storm is still almost a week out, it will be monitored closely and while most members point to it missing New Zealand, there is a chance that could change.
The Cone of Uncertainty for #CycloneJUDY.#Vanuatu is most directly affected.#NewZealand, for now, is outside the tracking - but could still brush us. We'll provide daily updates.
“There may still be an ensemble monitor or two that tracks it a little closer.”
Thunderstorms, heavy rain threaten North Island
It comes after MetService issued a heavy rain watch for Gisborne from 9am this morning until 6am tomorrow, with up to 100mm of rain possible just north of Gisborne City.
Meanwhile, Bay of Plenty east of Kawerau and Coromandel were under heavy rain watches until later today and a severe thunderstorm watch covered the North Island from Northland to Manawatū.
Auckland, Waikato, Waitomo, Taumarunui, Bay of Plenty, Rotorua, Taupō, Hawke’s Bay, Taihape, Wanganui, Manawatū and Northland were under the severe thunderstorm watch until 9pm today.
A Severe Thunderstorm Watch has been issued for parts of the North Island this afternoon and evening.
In Auckland, the city’s emergency management group said advice from MetService warned of a moderate risk of localised downpours in the city of up to 40mm of rain per hour - and “possibly more”.
“These thunderstorms are expected to be slow-moving, bringing localised heavy rain and hail for some,” AEM duty controller Fleur Aldridge said.
Satellite 🛰️ animation this morning reveals a better organised tropical low.
Note high cloud moving away ↔️ from the centre of convection (blob of bright colour).
This is outflow at high altitude, which helps grow the system.
“We are reminding Aucklanders to continue being vigilant as rainfall of this intensity can potentially lead to surface or flash flooding in low-lying areas.
”We also urge everyone to be cautious when driving as conditions could be hazardous with potential surface flooding and poor visibility.”
Driving conditions could become hazardous and people are urged to keep up to date with weather information.
Auckland Emergency Management reminded people to ensure their gutters and drains are clear of debris to lower the risk of flooding.
