Fallen trees are blocking roads in the South Island as wild winds strengthen, with motorists being warned to expect delays.

NZTA said contractors have been called in to clear fallen trees on State Highway 94 near Milford Sound, State Highway 74 in Canterbury and State Highway 6 on the West Coast.

The disruption comes as much of the country swelters under rising temperatures, with multiple heat alerts in place today.

MetService meteorologist Mmathapelo Makgabutlane told the Herald temperatures remain on track to shatter current heat records, with northwesterly winds from Australia already pushing highs past 30C in several regions by midmorning.

“Hawke’s Bay and Tairāwhiti Gisborne are still looking to be some of the hotter places in the country,” she said.

“Once those northwesterlies hit the coast, that’s when we’re expecting the temperatures to ramp up.”

Fifteen heat alerts are in place across Aotearoa today as the sizzling temperatures set in, with the national high currently nearing 34C in Hastings.

So far, heat alerts have been issued for Kerikeri, Whangārei, Whitianga, Tauranga, Whakatāne, Rotorua, Taupō, Gisborne, Napier, Hastings, Motueka, Blenheim, Kaikōura, Christchurch and Timaru.

Many heat alerts in the Bay of Plenty also extend through to tomorrow due to elevated temperatures overnight.

Given this, Makgabutlane noted “the nighttime doesn’t really bring much relief” for Paihia, Whitianga, Tauranga and Whakatāne.

A weather system simultaneously moving northwards over the South Island today is bringing strong winds and heavy rain to the southern regions first, and will eventually drag temperatures back down countrywide by tomorrow.

“Once the front has moved through, it might feel quite different”, Makgabutlane said.

Spiralling temperatures up to a sweltering 38C are forecast for today. Photo / Michael Craig

Most at risk of breaking high temperature records today are Whangārei, Whitianga and Napier; the latter’s January record of 36.9C in 1979 being only 0.9C above today’s forecast of 36C, MetService said.

And while a record-breaker is not expected, Auckland is among those to see its forecast high rise to 29C.

Forecast temperatures have been rising all week, with MetService saying some areas – including Northland, Coromandel and Hawke’s Bay – could break January records today.

Kerikeri already broke its January temperature record yesterday, exceeding the 32C mark, which smashed the previous record set in 1983.

The scorching heat and strong winds this weekend have sparked concerns about both fires and a rise in water-related incidents after at least two people drowned in separate incidents yesterday.

MetService meteorologist Rob Kerr said yesterday that heat alerts are issued a day out from hot weather, and are based on each centre’s usual summer highs and/or how many days of hot weather are forecast.

Hottest day yet on the cards

The hottest spell of the multi-day heat-streak is expected to hit today, with Hastings forecast to fry on 38C and neighbouring Napier not much lower at 36C.

The heat, combined with severe northwesterlies forecast for the lower North Island and much of the South Island, has raised wildfire risks to extreme.

“It will be dry in these northwesterlies, particularly in places like northern Wairarapa, Hawke’s Bay, Gisborne. Those are the areas that we’re focusing on for high risk of fires,” Kerr said.

He said people should be cautious when planning any barbecues in the next few days.

“Anything that’s lit, sparks can fly and get driven quite a long way and start fires,” Kerr said.

People in areas under alert should check in on their most vulnerable, including babies and the elderly, and ensure pets are “well cared for” with water and shade, MetService meteorologist Michael Pawley said.

“Heat alerts are more than just a typical hot summer’s day ... people can see some health effects from this sort of thing,” Pawley said.

‘Extreme caution’

Northland, Tairāwhiti, Hawke’s Bay, Wairarapa, Marlborough, Canterbury, Mid-South Canterbury and Otago face “spiking” fire danger today, Fire and Emergency New Zealand deputy chief executive of prevention Nick Pyatt said yesterday.

“Extreme caution [is] needed.”

Severe gales gusting up to 130km/h are also expected across a large part of the South Island and the lower North Island, posing an extreme fire risk when combined with scorching temperatures.

The MetService has issued a warning for severe gale northwesterlies gusting to 120km/h from early this morning through the day for Marlborough, Wellington, Wairarapa and Tararua district.

The high country and foothills of Canterbury are also under a warning for severe gale northwesterlies gusting 130km/h until 5pm.

Strong wind watches are also in place for eastern Canterbury and the lower South Island.

There is an extreme risk of fire in northern and eastern parts of the country this weekend, Fire and Emergency NZ says.

In contrast, an orange heavy rain warning has been issued for the headwaters of the Canterbury lakes and rivers about and south of Arthur’s Pass, and for Fiordland and parts of Westland, the MetService said on its website.

“There’s an elevated risk of thunderstorms, especially in the west of the South Island.”

“We can expect that there might be some damage to trees and power lines ... [and] with winds picking up, wildfires can get out of hand quite quickly,” Pawley said.

Further north, there are heavy rain watches across the Grey and Buller districts in the upper South Island this afternoon and evening.