Heavy showers and a few thunderstorm are forecast for the north of the country this morning.
The thunderstorms are expected to bring localised heavy rain, hail of up to 15mm and winds of about 90km/h.
Thunderstorms eased at dawn in Auckland, Waikato, Coromandel Peninsula and the western Bay Plenty but are expected hang around Northland until about mid-morning.
"A lot of those western areas of the North Island - Taumarunui north - have been getting hit quite hard with heavy showers but it does look a bit like it's starting to ease throughout the day and becoming fine in the east of the North Island today," said Clark.
The middle of the country - Wellington, Nelson and Marlborough - should get a mainly fine day today.
Canterbury was also looking mostly fine apart from an isolated shower or two this morning.
"For the West Coast they're also getting showers and rain for a time," said Clark.
Snow could fall up to 600m in Otago.
Another low will creep eastward over the country on Sunday, bringing strong winds to the southern and eastern coasts and possible severe southerly gales from Banks Peninsula to Gisborne.
Temperatures will drop again as skies clear overnight tomorrow.
On Monday, there's a small chance of heavy snowfall about north Canterbury and the Kaikoura Ranges above 400m.
Then mid-week, a ridge of high pressure is expected to build over the South Island as the southerly flow over the North Island eases.
Today's forecast
Whangārei: Showers with possible hail and thunderstorms, easing by midday and fine spells increasing. Gusty southwesterly, high of 16C
Auckland: Showers, with possible hail and thunderstorms before dawn, easing late morning and fine spells increasing. Strong southwesterlies, 15C
Hamilton:
Fine, apart from possible thundery showers before dawn. Showers return at night. Southwesterly, 14C high
Tauranga: Fine, apart from a few early morning showers. Southerly turning westerly afternoon, high of 15C
Napier: A few showers, clearing to fine in the morning. Strong southwest turning northwest evening, high of 14C
Wellington: A few showers, clearing to fine spells around midday. Strong southerly easing morning, afternoon northwesterly, high of 12C
Christchurch: A few early and late showers, otherwise fine with some high cloud. Southwest turning northeast for a time, high of 11C
Dunedin: Cloud increasing. Showers developing in the afternoon. Southwesterly turning northwest for a time, 10C high
(Source: MetService)