Oma gone: Cold snap coming

Cyclone Oma has swerved away from New Zealand, leaving in its wake a drizzly nuisance across the North Island.

WeatherWatch said Oma was trapped in the Coral Sea for the coming week, remaining "well away from New Zealand", as it heads back north — potentially towards New Caledonia.

MetService meteorologist Rob Kerr said Oma had diminished to the point where all of the characteristics that classified it as a tropical cyclone had passed except for gale force winds.

But unfortunately this doesn't mean today is going to be dry as cold air from the Southern Ocean is forecast to sweep over the country.

Kerr said last night: "We're going to see all the temperatures dive right across New Zealand tonight and be much cooler than it has been over the last few weeks."

Strong wind and rain is set to hit eastern parts of both islands today, Kerr said, with heavy rain watches beginning overnight in Hawke's Bay, Wairarapa and Canterbury foothills, continuing through much of Sunday.

WeatherWatch said today's southerlies would be made stronger and colder by a large high in the Tasman Sea. The forecaster said many areas could expect "the usual" unsettled conditions.

Occasional showers are forecast for Auckland today, and some may be heavy. A high of 21C is expected.

Tauranga will have intermittent showers with a high of 23C and Wellington can expect rain with a high of 15C.