Thunderstorms and heavy showers expected over most of the county this afternoon look set to continue through the weekend.
For most of the North Island things looked pretty grim, there was a moderate to high risk of thunderstorms in the afternoon and early evening, particularly about inland areas.
This risk brought the possibility of heavy rain up to 25mm an hour and hail up to 15mm in diameter, MetService said.
Auckland, and areas southward, carried a moderate risk that some of the thunderstorms may become severe which could bring downpours of up to 40mm per hour.
MetService had not yet put a severe thunderstorm watch in place for Auckland.
In the South Island, there was a moderate risk of thunderstorms during the afternoon and evening for inland parts of the South Island from the ranges of Nelson and Marlborough down through the ranges of Buller and the Southern Alps to northern parts of the Southern Lakes and Central Otago.
There is also a moderate risk that some of the thunderstorms about Nelson Lakes, and the ranges of Buller and far northern Westland becoming severe.
Looking ahead to the weekend, a low lying west of the North Island would weaken as it drifts northward as a large ridge of high pressure would spread over the country from the Tasman Sea.
"A combination of afternoon heating and wind convergences are likely to produce showers over some inland parts of both islands during this period, with possible thunderstorms and localised heavy rain."
The ridge from the Tasman Sea would drift to the east on Tuesday as an active front moved on to the South Island from the south Tasman Sea bringing rain to western areas.
"There is low confidence of rainfall accumulations approaching warning criteria in Fiordland and southern Westland on Tuesday.
"Additionally, strengthening northwesterlies precede this front and there is low confidence of northwest gales becoming severe in exposed parts of inland Canterbury, Otago and Southland during Tuesday," MetService said.
Whangārei: A few showers, especially after midday, possibly heavy and thundery. Light winds. High 24C Low 15C
Auckland: A few showers from late morning, with afternoon thunderstorms, possible hail and localised downpours. Light winds. High 24C Low 15C
Tauranga: Fine apart from a morning shower or two. Light winds and sea breezes. High 23C Low 16C
Whanganui: Mainly fine, chance afternoon and evening shower. Light winds. High 23C Low 13C
Napier: A few showers this afternoon and early evening, with thunderstorms, possible hail and localised downpours. Light winds. High 23C Low 13C
Wellington: Cloudy periods. A few showers from midday, mainly north of the harbour, and possibly heavy. Light winds. High 20C Low 13C
Christchurch: Morning low cloud and possible drizzle then fine spells. Cloud returning tonight. Northeasterlies. High 20C Low 11C
Dunedin: Morning cloud then fine spells. Becoming cloudy again tonight. Northeasterlies. High 21C Low 12C