Your weather: NZ in for heavy rain, thunderstorms and temps in the high 20s

Most of the country is in for a mighty fine Tuesday, except the South Island's West Coast where heavy rain and even thunderstorms are forecast.

The forecast is still looking good for the start of Easter too, when fine weather is forecast through most places on Good Friday.

MetService meteorologist Bill Singh said an active cold front was arriving in Fiordland this morning, bringing heavy rain and thunderstorms to the west of the South Island, and warm but strong northwesterlies to the east.

The east coast is the place to be today. Temperatures will reach 27C in Christchurch, and 26C in Napier and Gisborne, which can expect warm northwesterlies.

Fine weather is forecast for most of the rest of the North Island today due to a large ridge. Hamilton is forecast to reach 26C, Auckland and Whangarei 24C, and Tauranga 23C.

The heaviest rain is expected in Fiordland and Westland south of Otira, where significant spillover into the headwaters of the Otago and Canterbury lakes and rivers is expected. A warning is in force for these areas until tonight as up to 150mm of rain is forecast in places.

Winds could gust to 120km/h in the Canterbury High Country and a warning for severe gale northwesterlies is in force.

The southerly front is expected to reach Nelson and parts of Buller tonight, bringing rain. It will move into Wellington tomorrow morning, before stalling just to the north and slowly moving into central areas on Thursday.

By Good Friday the front is expected to reach the upper North Island, but it will weaken as it moves north and only a few showers are expected in Northland, Auckland and Bay of Plenty.

"Good Friday is looking good for most places, except Fiordland," Singh said.

WeatherWatch NZ analyst Philip Duncan said Easter Weekend was shaping up pretty positively for most regions. Mostly light winds and warm days are forecast.

On Good Friday a few showers are possible first thing around Hawke's Bay, Gisborne and Northland - and potentially very early in the Auckland region.

However, a large high over central New Zealand will keep the weather dry everywhere with mostly light winds.

On Saturday, a cold front in the Southern Ocean will clip the lower South Island, breaking the front in half and sending some rain up the West Coast, fizzling out by the time it reaches Westport later in the day.

Most other regions will be dry but some rain is possible briefly in Southland and Otago and a few light showers may also hug Coromandel Peninsula to the east and Bay of Plenty.

Light winds are forecast in the North Island from and a westerly flow over the South Island.

On Easter Sunday a bit of cloud and a few light showers are expected in the western side of both islands, mostly the West Coast and the southwest corner of the North Island. However, it should be mostly dry, with light winds.

On Easter Monday, heavy rain returns to the West Coast. A few showers may affect the North Island's western side but most other places will be dry with fairly light winds.

Today's weather

Whangarei

Mostly sunny, chance afternoon shower. Northeast breezes. 24C high, 16C overnight.

Auckland Mostly sunny. Northeast breezes. 24C high, 17C overnight.

Hamilton Morning fog, then mostly sunny, before clouding up at night. Light winds. 26C high, 13C overnight.

Tauranga Cloudy with some drizzle morning and evening, otherwise sunny spells. and chance shower. Light winds. 23C high, 17C overnight.

New Plymouth Mostly cloudy, but afternoon sunny spells. Chance morning or evening shower. Northerlies. 22C high, 17C overnight.

Napier Fine. Northeast breeze. 26C high, 16C overnight.

Wellington​ A few morning showers then afternoon fine spells. Strong, gusty northerlies. 21C high, 17C overnight.

Nelson​ Fine spells. Chance morning shower. Rain developing at night. Northerlies. 22C high, 17C overnight.

Christchurch​ High cloud. A few drops of rain mid evening. Gusty northerlies. 27C high, 11C overnight.

Dunedin​ High cloud, with brief afternoon rain, then evening fine spells. Northeasterlies dying out afternoon. 22C high, 11C overnight.