Thunderstorm hits Hawke's Bay rush hour, spring scorchers to continue

The late-October heatwave in Hawke's Bay took a dramatic turn on Friday afternoon with sudden, but forecast, thunder, lightning, hail, and even the threat of the beginnings of a small tornado.

After temperatures topped 29C earlier in the week, the late-afternoon burst today initially appeared short and sharp, bringing back near-anniversary memories of the floods of November 9 last year.

It sparked a flurry of calls to emergency services, including four in six minutes from 4pm, across Napier residential areas Pirimai, Taradale and Onekawa, and urban and horticultural area Meeanee. There were two more calls by 4.30pm.

Appliances from Napier, Taradale and Hastings had been sent to the incidents, a prelude to a weekend that is otherwise expected to be changeable, from fine weather in Napier on Saturday to rain again on Sunday.

A Fire and Emergency New Zealand spokesman in Wellington said of the stormy spell: "It conquered and left."

Storm damage in Onekawa on Friday afternoon. Photo / Ian Cooper

He said they received about five to six calls and were busy for a short while with a bit of flooding "just gutterings not being able to handle it".

At Brookfields Rd, a Hawke's Bay Today photographer videoed the scene as a tornado threatened to form in a paddock before disappearing from sight.

The heat is set to continue into Hawke's Bay's this weekend, with highs in the mid-20s, this time without a thunderstorm in sight.

In a week of record-breaking October temperatures and sweltering overnight highs, thunderstorms were always expected to round out the tropical weather trifecta on Friday evening.

A severe thunderstorm warning was issued for Hawke's Bay by MetService at 3.24pm, updating the severe thunderstorm watch issued between 1pm and 8pm.

Metservice meteorologist Peter Little said there had been thunderstorms and lightning across a wide area from North Canterbury to southern Waikato during the day, and a specific warning for Napier-Hastings to Wairoa was issued at 3.24pm and lifted at 4.13pm.

There had been about 5000 lightning strikes in the North Island, about 2000 of them in Hawke's Bay, where the heaviest rain recorded in the hour to 4pm was 20.6mm at Hawke's Bay Airport.

MetService meteorologist Lewis Ferris said that an initial watch was put in place for the region due to the difficulty of predicting where a thunderstorm will form.

"Thunderstorms are different to other severe weather forecasts, as the precise location of where the thunderstorm will form is unknown.

"Once we know the likelihood of where the thunderstorm will form, then we will issue the severe weather warning," Ferris said.

Ferris said the thunderstorms were fuelled by the warm weather we have been experiencing in Hawke's Bay, which is set to continue over the weekend.

"Moving into the weekend, Saturday's weather will be cloudy, with light northwesterly winds and a high of 22C," he said.

Ferris said balmy overnight temperatures will continue on Saturday, with a 17C overnight low meaning people will most likely be kicking off the blankets as soon as they get under them.

"Sunday should however provide some relief from the humidity, with a southerly change, a few showers, and cooler air and overnight temperatures," he said.

Ferris said a high of 24C on Sunday will make way for a settled start to the week on Monday, with light clouds and a slight drop in temperature.