Hot summer day to end in thunderstorms, with 40C temps expected early in week

Sunday, 28 January 2018

Bill Taulele, 8, makes the most of a sweltering summer day in Blenheim.

A severe thunderstorm watch has been issued for many parts of the country just one day after weather records were smashed in Wanaka.

On Saturday, the western Otago holiday destination recorded its hottest ever day since records began in 1972, with 35.2 degrees Celsius measured at 4.15pm.

Two-year-old Jack Swanney cools down with an ice cream in Pohangina, near Palmerston North.

On Sunday, MetService issued a watch for Waikato, Waitomo, Taumarunui, Taupo, Taranaki and Taihape.

The forecaster said the combination of another very warm, humid day and light winds had allowed clouds to build up, producing heavy showers and thunderstorms.

* Temperatures could hit 40 degrees

The fountain at Mission Bay in Auckland offers some welcome respite from the heat.

* Warm and wet, is this New Zealand's new summer?**

Between 4pm-9pm, some of those thunderstorms could be severe, with localised downpours of 20-40 mm per hour, MetService said.

'Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips.

'Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain.'

Meanwhile, the mercury was set to skyrocket again on Monday and Tuesday.

Niwa principal forecasting scientist Chris Brandolino said 40C was 'a distinct possibility'.

'Monday it's going to be hot. But Tuesday, that's when the heat is likely to be at its highest,' he said.

With students slowly filing back into the classroom from this week, it remains to be seen whether they will be affected by soaring temperatures.

The Ministry of Education is currently promoting its internal air quality and thermal comfort guide with schools.

Its head of education infrastructure, Kim Shannon, said it recommends indoor temperatures be maintained at 18-25C.

But Shannon said it was not always possible to keep classrooms within that range.

'The decision to remain open or to close a school due to weather is for the board of trustees and we are here to support them as needed,' she said.

Shannon said parents should contact their child's school if they were concerned about the heat.

On Sunday, MetService said the heat had been 'well above average' for most parts of the country.

'Already this month we have had a few records being broken for hottest temperatures and this heat is set to continue into the working week.'

Metservice said most of New Zealand would see more blue skies on Sunday, with temperatures expected to range from the mid-20s upwards.

At midday, Hunua in rural south Auckland was the hottest place in the country, with 28.6C recorded.

Hamilton, Palmerston North and Masterton were all expected to see 30C highs later in the day.

Upper Hutt man Chris Stuart said the thermometer outside his home was reading 34C just before 1pm.

'It's just extremely hot, and it's the humidity as the day progresses – you just constantly feel soaked.'

Stuart, from the United Kingdom, said he was not used to the hot weather and had turned to extreme measures to keep cool: 'I'm driving around in the car with the air conditioning on.'

MetService said its forecast maximum temperatures were often different to those people saw on their personal thermometers, as its weather stations recorded the temperature out of direct sunlight and with ample ventilation.

Thermometers placed near buildings, trees and other objects could also show higher temperatures due to heat radiation.

'So, when your thermometer tells you the temperature is much higher than the MetService forecast, consider a few things. Has your car been sitting in direct sunlight? Is your thermometer inside in a stuffy room?

'Whilst it will feel that hot there and then, this is not the ambient air temperature of the environment outside.'