Thunderstorm watch for Rotorua

Brian Holden said farmers are likely to welcome the rain. Photo / Ben Fraser

A severe thunderstorm warning is in place for Rotorua as the city experiences more wet weather. Police are warning motorists to take extra care.

MetService has issued a severe thunderstorm watch warning for the Bay of Plenty and parts of the North Island as a sub-tropical low moves south.

The low is expected to bring heavy rain to these areas today, but the rain is to ease early tomorrow, with just a few showers forecast.

This is an alert for potential downpours associated with a rainband moving south over the northeast of the North Island this afternoon. The threat is expected to ease by this evening.

A warning has been issued for heavy rain for the Bay of Plenty, Rotorua and Gisborne and a watch for heavy rain in Coromandel and Hawke's Bay. In addition to the heavy rain there is a risk of thunderstorms embedded in the rainband producing localised downpours with rainfall rates reaching 25 to 35 mm/hr.

Rainfall of this intensity can cause 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.

Springfield-based weatherman Brian Holden said 19mm of rain fell during a 24-hour period between Wednesday night and last night, the heaviest rainfall since March 26 and 27.

Mr Holden said while the amount of rain was not unusual for this time of year, the humidity and warm temperatures Rotorua has had since the start of April was.

"Rotorua is getting a good, healthy dose of rain. This isn't unusual but the humidity is, it's been so hot," he said.

Rotorua had its warmest April day for the past 50 years on Sunday when it reached 27C.

Mr Holden said he had recorded a maximum temperature of 27.3C at his Springfield weather station. The previous warmest April day was 25.2C in 2006.

Mr Holden said farmers are likely to welcome the rain, after the region only got patches of rain in March, and little to no rain in February.

He said Rotorua was likely to expect showers this weekend, which are expected to ease by the beginning of next week.

The forecast has prompted calls from police for motorists to take care on wet roads.

Recent crashes on the region's roads were a timely reminder for all drivers to check their cars, said Acting Bay of Plenty District road policing manager Senior Sergeant Fane Troy.

"People need to drive to the conditions but also ensure vehicles are safe and they have significant tread depth and their windscreen wipers work," Mr Troy said.

"The amount of rain we have had lately means people need to be aware of puddles and aqua planing."

Police recommend people give their cars a "TWIRL" and take it to an expert if they think anything is wrong.

TWIRL stands for Tyres, Windscreen, wipers and mirrors, Indicators, Rust and Lights.

One person who was happy for the rain was Rotorua triathlete Olly Shaw, who is competing in tomorrow's XTERRA flagship event.

"I'm stoked with the rain," he said.

"I've been smiling all day. This is my seventh year and I've always wanted a year of wet weather. It gives the people who know the course well a big advantage."