MetService has issued severe weather alerts along the east coast of New Zealand from Gisborne to Canterbury for this afternoon, as a cold snap sweeps the country and drops temperatures by 10C in minutes.

The forecaster warned those in the firing line to “batten down the hatches”.

Severe thunders and hailstorms have been forecasted for Gisborne, for between 5pm and midnight today; and in Tararua, Wairarapa, Wellington, Marlborough and Canterbury from now to 7pm.

Gales in Wellington and coastal Wairarapa, forecasted for between 3pm and 6pm; and along the Kaikōura coast from 1pm to 4pm could damage trees, down powerlines, destroy unsecured structures and make for dangerous driving conditions, MetService said.

Wind speeds are expected to reach up to 130km/h in places.

Auckland, meanwhile, should remain mostly cloudy with only a few showers today. The high temperature was forecasted to reach 16C, although it had only reached 13C by 2pm. Tuesday was expected to be fine apart from some light isolated showers in the west before dawn. Wednesday should also be fine.

MetService meteorologist Clare O’Connor said the weather was being driven by an intense cold front moving northwards, colloquially known as a “southern buster”.

O’Connor said: “A ‘southerly buster’ is a particularly strong cold front, characterised by blustery wind changes and a large drop in temperatures.”

She said temperatures around the country could drop by 10C “in a matter of minutes”.

The National Institute of Water and Atmospheric Research (Niwa) shared sped-up video footage of the moving over Christchurch, with thick, dark clouds barreling over the landscape and obscuring the previously clear skies.

Into Tuesday, heavy swells of up to 6m were expected for the east coast of the North Island and the Chathams. Tairāwhiti Civil Defence posted about the wave warning, saying it was expected to cover Mahanga to Lottin Pt from 9am tomorrow until 6am Wednesday.

O’Connor said the weather should begin to calm in other areas, with a high-pressure system expected to build over the country. Wednesday should begin with below-average temperatures, particularly around the central North Island, she said.

“The cold snap is short-lived with above average temperatures expected from Wednesday afternoon as milder westerly winds develop about the lower half of the South Island, then spread northwards over Thursday,” she said.

“Another swing to the lower end of the temperature scale, and a burst of heavy rain could be seen over the weekend.”

O’Connor recommended anybody with plans to hit the outdoors this week to keep up to date with the latest forecasts.

Raphael Franks is an Auckland-based reporter who covers breaking news. He joined the Herald as a Te Rito cadet in 2022.