An atmospheric river is fueling intense downpours on northern and western regions, which might result in more than double a month’s amount of rain.
The tropically-charged storm is causing disruptions for commuters in Auckland and may cause slips and flooding across the country.
Fire and Emergency NZ (Fenz) said are “closely monitoring” the unfolding event and are on standby to send resources where required.
The worst of the weather, however, is expected to skip Central Auckland as the atmospheric river moves along the western side of the country. But ferry services across the Gulf Harbour are cancelled on Thursday as a precaution.
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However, Western parts of Auckland may not escape unscathed, with MetService forecasting periods of heavy rain and issuing a heavy rain watch for the area.
MetService is expecting the Northland, Bay of Plenty, Tasman, and Fiordland regions to be the worst affected by the downpours, and warnings and watches have been made.
Some 100 to 120mm of rain is expected to drench Northland until 9pm today, while the area is currently under a heavy rain warning which began at midday yesterday.
Fire and Emergency deputy national commander Brendan Nally said crews are on standby to help those if needed during this extreme weather and are closely monitoring the forecast.
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“Northland is already seeing some impacts of heavy rain, so we have sent resources, including some of our [urban search and resuce] capability to Kaikohe in Northland,” Nally said.
Taranaki, north of Opunake to Whangamomona, is also under the heavy rain warning, with a massive 350 to 450mm of rain about Mt Taranaki. Some 150 to 200mm of rain is expected west of Urenui to Stratford, and 100 to 150mm further east, with peak rates of 25 to 35mm/h.
MetService advises residents in these areas that this is a “significant amount of rain” and the warning may be upgraded to red this morning. The warnings span until Friday morning.
The Nelson, Marlborough, Tasman, Tongariro National Park and Waitomo regions are also in the firing line. Residents should expect 200 to 300mm of rain in some places and 100 to 150mm elsewhere with peak rates of 15 to 25mm/h.
More rain warnings extend down the western coasts of both islands, with a warning for Wellington to Horowhenua, Westland south of Otira, and Fiordland north of Doubtful Sound.
Some areas of these regions will see thunderstorms that may bring rain at 35mm/h at their peak.
Nally said further Fenz deployments may occur as the event unfolds and authorities receive more clarity on the conditions on the ground.
“Although there is still some uncertainty about exactly where the rain will hit, we are ready to respond where we are needed. We have extra resourcing ready to be deployed at short notice,” Nally said.
“Our focus is on supporting our communities, some of which have already been affected by previous events this year, most notably Cyclone Gabrielle.”
MetService meteorologist Dan Corrigan warned residents who are likely be impacted to pay close attention to forecasts as their severe weather warnings could change as the storm evolves.
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“MetService is keeping a close eye on this rain band, but there is still some uncertainty surrounding the details of when and where the heaviest rain will fall later this week,” Corrigan said.
The storm has boomeranged back on the country after dumping heavy rain in Northland and Coromandel earlier this week.
Yesterday, persistent rain caused flooding and rising river levels and triggered slips and cut off townships in the Bay of Plenty.
The Whakatāne River reached a second warning level according to the Bay of Plenty Regional Council as 230mm of rain fell in the catchment.
“We are advising farmers with stock on low-lying areas adjacent to the Whakatāne and Tauranga Rivers to immediately move stock to higher ground,” a spokesperson from the council said.
Photos emerged yesterday aftermath of a large slip in Whakatāne that cut power to a number of households. The slip took out powerlines and affected 674 customers.
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The townships of Tāneatua and Rūātoki were also cut off due to slips.
The low-pressure system has rolled over the country from the Tasman Sea, picking up and bringing lots of warm air and water.
Corrigan said a stubborn high-pressure system off New Zealand’s east coast was stopping the storm from following its normal path away from the country.
The humid, unsettled northerly flow was expected to affect the country until at least early next week, with multiple fronts embedded in the system likely to bring more rain.