MetService has issued a severe thunderstorm warning for the central North Island as storms begin to lash the area.
The warning affects people in Bay of Plenty - including Whakatane - Hawkes Bay, and Taupo, where the thunderstorms are expected to bring torrential rain.
The forecaster warned this could result in surface or flash flooding around streams, gullies and urban areas, and make driving conditions extremely hazardous.
The thunderstorms are moving east.
The Ministry of Civil Defence and Emergency Management advises that as storms approach you should:
- Take shelter, preferably indoors away from windows
- Avoid sheltering under trees if outside
- Move cars under cover or away from trees
- Secure any loose objects around your property
- Check that drains and gutters are clear
- Be ready to slow down or stop if driving
- Beware of fallen trees and power lines
- Avoid streams and drains as you may be swept away in flash flooding
Kiwis hoping for a sunny long weekend will have to keep their fingers crossed, as rain is expected at some point. And you may want to keep the electric fan close as humidity is expected to last as well.
MetService meteorologist Chelsea Glue says conditions will improve around the country over the weekend.
"It will be hot and humid in the North Island," she says.
"There's showers around much of the island today and tomorrow, and a low risk of severe thunderstorms in Gisborne, Hawke's Bay and Taupo this afternoon or evening."
The South Island will be cooler, with Sunday the warmer day for much of the island.
Nelson is expected to be dry and warm on Monday for its anniversary celebrations.
WeatherWatch head forecaster Philip Duncan says heavy showers are possible across the upper North Island on Saturday.
"Not everyone will get a downpour - they will grow with afternoon heating, and drift where the sea breezes and light winds carry them," he says.
"There may also be a couple of light showers around coastal Canterbury and eastern Marlborough on Saturday - otherwise mainly dry."
Most of the country will be dry by Sunday, he says.
"But around Northland, Auckland, Waikato and Coromandel Peninsula, there is the chance of an afternoon cloud build-up, downpours, and even isolated thunderstorm as the hot and humid weather continues."
Main centres forecast:
Fine spells, isolated showers, improving conditions. Highs: Today 28C, Saturday 27C, Sunday 26C, Monday 25C.
• Auckland: Fine spells, isolated showers, improving conditions. Highs: Today 26C, Saturday 27C, Sunday 26C, Monday 25C.
• Hamilton: Fine spells, showers, some possibly heavy. Highs: Today 26C, Saturday 27C, Sunday 26C, Monday 25C.
• Tauranga: Fine spells, light rain turning to heavy showers with low risk of severe thunderstorms. Highs: Today 26C, Saturday 27C, Sunday 25C, Monday 24C.
• Wellington: Cloudy periods with the odd shower. Improving conditions, with good day on Sunday. Highs: Today 20C, Saturday 19C, Sunday 21C, Monday 23C.
• Christchurch: Quite cloudy with patches of drizzle. Long fine spells on Sunday. Highs: Today 20C, Saturday 16C, Sunday 21C, Monday 24C.
• Dunedin: Cloudy today with a few showers. Improving conditions over the weekend. Highs: Today 15C, Saturday 16C, Sunday 17C, Monday 24C.