Parts of New Zealand are bracing for a battering of rain and thunderstorms today as a tropical cyclone strengthens near Australia.
MetService has placed several warnings and watches across both islands, with torrential rain expected to hit Gisborne in the north and Westland in the south this evening and through to tomorrow.
In Gisborne, rain was expected from 9pm today with peak rates of 20 to 30mm/h tomorrow morning.
MetService meteorologist Claire O’Connor told The New Zealand Herald the rain was coming from a lower pressure system descending on New Zealand from the north.
“Given the way the winds go around, it will direct the rain towards the eastern coast - so that’s where those warnings come into play there.”
Despite the forecast, it was a sweltering day for much of the country on Sunday, with Gisborne and Auckland recording 27degC by mid-afternoon.
The hottest place by mid-afternoon was Masterton which had reached 30degC, and Napier, Palmerston North and Hamilton close behind on 28degC.
In the South Island it was slightly cooler, with most regions sitting between 20degC and 25degC. The coldest place in the country is Stewart Island, on a pleasant 18degC.
In Tongariro National park, lightning has already been detected with the potential for severe thunderstorms to develop later today.
Taumarunui, Taupō and Taranaki are all under a severe thunderstorm watch until 9pm tonight.
Further south, there’s a watch of heavy rain for Westland which O’Connor said was caused by a front moving up from the south.
“There’s a bit of precipitation that will impact the West Coast - but it’s fast moving, so it won’t have as much impact as the weather the other day.”
On Friday, the West Coast was under a state of emergency due to torrential rain that caused rivers to rise rapidly and forced the closure of State Highway 6 between Haast and Hokitika for a time.
O’Connor said despite more rain being forecast, it wasn’t all bad news - a much-needed break in the high heat and humidity is also forecast to drift across the country in the coming week.
“With this feature moving up the country, these cooler south-[westerlies] go right across the country flushing out the humidity and the heat as well.”
Overnight temperatures could drop into single digits in the South Island this week and Invercargill is looking at a chilly Wednesday - with a high of just 13degC forecast.
Further north it’s a similar story with overnight temperatures expected to dip to half of their current temperature.
“The highest [temperature] I can see overnight on Wednesday is 15 degrees,” O’Connor said.
Tropical cyclone strengthening
O’Connor said the tropical cyclone that is strengthening over the Coral Sea is looking like it will impact Australia before possibly making landfall in New Zealand.
The cyclone is forecast to hit Australia on Monday, but O’Connor said it was difficult to know whether it will strike New Zealand, and how severe it will be if it does.
“It’s going to hit Australia, particularly Queensland but in terms of for New Zealand, it’s still quite far out that a lot of uncertainty and in the models that we can’t say for sure what impact would be for New Zealand if it did come our way.”
Forecasters are closely tracking potential for a tropical low over the Coral Sea to form into a cyclone system, with Australia’s Bureau of Meteorology currently giving a “high” chance (or 55%) of it reaching cyclone strength by early next week.
