Sodden summer: Heavy storms to lash Auckland

Race-goers brave the rain at Ellerslie Racecourse in Auckland earlier this month. More of the same awful weather is expected this week. Photo / Steven McNicholl.

Heavy rain and thunder warnings are in place for several parts of the country today.

Thunder is possible over much of the North Island, including Bay of Plenty, Taranaki and Auckland later this evening, MetService forecaster Rochelle Fleming said. The top of the South Island might also experience thunder.

Meanwhile, heavy rain warnings are in place in Nelson, Richmond Range, Rai Valley, Marlborough and Taranaki.

About 25mm to 35mm could fall an hour, with 100mm to 180mm of rain expected in total.

Rain is expected in Auckland today as well.

"There's a rain band to the west of Auckland which is expected to move across the city," Ms Fleming said.

"The weather will deteriorate during the day with thunder possible this evening."

Heavy fog, which forced airlines to cancel several flights in and out of Wellington yesterday, has lifted in the capital, she said.

Joe Pettigrew, 11, of Mairangi Bay plays with dog Hector on Mairangi Bay beach as the nice weather starts to turn on Monday morning. Photo / Nick Reed

"There's not much wind there now. It's warm and humid with some showers likely this afternoon."

The forecast came with a warning that streams and rivers could rise rapidly due to heavy rain, causing slips and surface flooding, and making driving conditions dangerous.

"Periods of rain in a very humid northerly flow ahead of the low are expected across northern and western parts of New Zealand," the MetService said.

Flights have resumed as normal in Wellington this morning. Air New Zealand and Jetstar have added additional flights to assist the thousands of passengers affected by cancellations and delays.

Heavy rain in the south was spurred by a low pressure system over the Tasman Sea that is slowly approaching New Zealand.

In the Cook Islands, Victor was making its presence felt last night.

A staff member at Rarotonga's Waterline Beach Bar and Grill said the sea nearby was choppy but northern parts of the archipelago were worse off than Rarotonga.

The tropical cyclone was expected to intensify until Tuesday, and crawl south.

"The system should remain over open waters between Niue and the southern Cook Islands," the MetService said.

Victor is expected to move slowly south on Tuesday to lie southeast of Niue and west of the southern Cook Islands.

MetService said the storm was expected to die down mid-week, fading across Thursday, though it would still be powerful enough to be labelled a tropical cyclone.

There was a chance Victor would move northwest on Thursday, making landfall over Niue on Thursday night or soon after, the MetService said.