Weather: Heavy rain, severe gales set to hit top of North Island today, moving south through the week

New Zealanders hoping to squeeze a little more outdoor time from the last day of school holidays can expect thick cloud cover over much of New Zealand today, bringing with it sporadic showers or drizzle. But more severe weather is close behind.

MetService says a low-pressure system is currently zeroing in on New Zealand, with Northland set to see the first of it this evening as it slowly moves southward in the coming days.

"This front is preceded by a broad band of rain, with some heavy falls," MetService predicts. "The largest rainfall accumulations are likely in the north and east of Northland, northern Auckland and Coromandel Peninsula. Northeast winds are also expected to approach severe gale (force) over Northland and Auckland for a time."

Mōrena Aotearoa. This morning's satellite image shows thick high cloud covering much of the country today, but clear skies for the lower half of the South Island. Keen eyes might see a small circulation in the cloud south of the SI. https://t.co/Yjbq0jgaoz for your forecast
^DM pic.twitter.com/mQhg6l2AlN

— MetService (@MetService) July 23, 2022

A 26-hour heavy rain warning is in place for Northland starting at 6pm today. Residents should expect it to peak on Monday morning and afternoon with downpours of up to 10 to 15mm per hour. Areas from Whangārei to Kaitaia can expect roughly 100 to 140mm total rainfall during the period, while other areas of Northland could receive up to 90mm.

Meanwhile, a strong wind watch for Northland starts at midnight, with gusts of up to 120km/h. Independent weather forecasting company WeatherWatch.co.nz has described a "slow-moving squash zone" for the Upper North Island as it is battered by severe east to northeast gales tomorrow.

Large waves are expected to accompany the rain and strong winds in coming days, MetService predicts. Photo / Supplied

The weather system is expected to move down to the Auckland region on Monday and Tuesday, with a heavy rain warning in place starting at 3am, followed by heavy rain warnings in Coromandel Peninsula starting at 7am and Bay of Plenty by midday.

Strong winds, with gusts of up to 110km/h, are also predicted for Auckland and Great Barrier Island tomorrow.

Heavy rain and severe gales are expected for parts of New Zealand this week, MetService says. Photo / Supplied

"Strong wind gusts could damage trees, powerlines and unsecured structures," MetService warns. "Driving may be hazardous, especially for high-sided vehicles and motorcycles."

The low and its associated fronts are expected to continue south until Thursday.

Heavy rain watches are in place for Tasman and Marlborough tomorrow afternoon and evening while heavy wind watches will be in place for parts of Coromandel, Waikato and Buller.

NI boaties: As well as the strong winds from the next approaching low pressure system, large combined waves are also expected in the next few days, which could make for hazardous conditions on the water. Check https://t.co/GgW2EUIpBs for your latest marine forecasts ^DM pic.twitter.com/A2qAOMKub3

— MetService (@MetService) July 22, 2022

MetService predicts there is a 40 per cent likelihood rainfall could reach warning criteria in eastern Marlborough, Canterbury and North Otago by Tuesday and Wednesday.

"The rain will likely fall as snow above about 900 metres over the South Island, which may affect some alpine passes," MetService says. "The low should weaken over the South Island on Thursday, while a disturbed westerly flow covers the North Island."

Boaties can expect choppy seas with large combined waves in the next few days as the strong wind kicks in. It could make for hazardous conditions on the water, MetService warned this weekend.