Weather: Heavy rain expected for several areas in North Island

Auckland is one of many areas in the North Island likely to be pelted with rain today. Photo / Dean Purcell

Residents in several parts of North Island are being advised to stay alert, with the potential for heavy rainfall over the next few days.

Monday afternoon and evening are predicted to see increased rainfall rates and potentially thunderstorm activity over parts of the central and upper North Island due to moisture associated with a slow-moving front, midday heating and chilly temperatures at higher elevations.

Also on Monday, there is a moderate chance of thunderstorms from eastern Northland to Waitomo and over to the western Bay of Plenty. In the evening, this risk narrows to Waikato, Auckland and the western Coromandel Peninsula.

📅Wondering how the start of the workweek is shaping up?

🧐Take a peek at this rainfall accumulation map to the end of Tuesday

⚡️Plus, keep an eye out for potential thunderstorms tomorrow afternoon/evening making appearances in spots in both the North and South Island pic.twitter.com/EVRRSyF9Qe

— MetService (@MetService) November 19, 2023

There is a low chance that these thunderstorms might be severe, resulting in isolated downpours of 25 to 40mm/h in Auckland, Waikato and the western Bay of Plenty. These storms may also be accompanied with heavy rain, 10 to 25mm/h and hail with a diameter of 5 to 15mm.

According to MetService, there is “moderate confidence” that Monday and Tuesday’s heavy rain in Gisborne, Hawke’s Bay and eastern Taihape would necessitate a warning.

Hawke’s Bay is under a rain watch and warning through early Tuesday morning. From Sunday night to Tuesday morning, 120–150mm of rain is predicted to fall in the vicinity of the Ruahine Range.

“The heavy rain warning is mainly for the ranges, so the Ruahines and other inland ranges of Hawke’s Bay. Much of the rest of the area is covered by a heavy rain watch, pretty much from Gisborne all the way down to Wairarapa just north of Carterton,” MetService meteorologist Philippa Murdoch said.

“We say to be careful because rivers and streams can rise rapidly, and you can also get surface flooding and slips as well.”

Hawke’s Bay Civil Defence Emergency Management Group said on social media the rainfall would likely be around one-in-five-year levels, and that its widespread nature could see a “small to moderate” rise in river levels.

🌧️🌧️A persistent low pressure system continues to bring wet weather to parts of the North Island in the days ahead

🟠🟡Stay informed with the latest Severe Weather updates, now covering Tairāwhiti Gisborne, Hawke's Bay, and the Wairarapa, where rain lingers into Tuesday pic.twitter.com/43ymQXxqR0

— MetService (@MetService) November 18, 2023

“In Central Hawke’s Bay, this widespread rain may cause surface flooding and roading issues.”

Murdoch said the warning area would see accumulations of 120-150mm of rain, however, the areas under watch would not see this much.

Although not until the middle of next week, the South Island is also under threat. According to MetService, a “couple of fronts” are expected to affect the island on Wednesday and Thursday.

“These may bring brief heavy rain to Fiordland and Westland, and strong west to northwest winds to exposed parts of Southland and Otago,” MetService said.

“However, currently confidence is very low that warnings will be required for heavy rain or strong winds.”