The upper North Island is set to hammered by heavy rain and buffeted by gale-force winds on Sunday, putting a damper on the long weekend for Queen's Birthday travellers - but also bringing much-needed rain to the drought-stricken north.
The convergence of a powerful high and a small low is developing a subtropical cyclone, according to WeatherWatch head forecaster Philip Duncan, with rain clouds funneling down from the subtropics expected to hit northern and north-eastern New Zealand.
Heavy rain will strike the upper North Island later on Sunday, leading to risks of floods and slips. Some spots may see more than 100mm of rainfall within 24 hours, Duncan says.
Raging gales will be strong enough to cut power in some exposed upper North Island areas on Sunday night, the forecaster warns, so it may pay to have some candles on hand. Meanwhile the Hauraki Gulf, Great Barrier Island and the north of Auckland may be battered by gusts of up to 80 or 90km/h, with possible isolated power cuts.
"Winds peak overnight tonight [and] Monday morning - and ease into Monday as they slide down the North Island in a similar fashion and peak winds start to drop," Duncan says.
Eastern Waikato is at the highest risk overnight and on Monday morning, with gusts likely to reach more than 120km/h on the western side of the Kaimai Range and Coromandel Peninsula.
A heavy rain warning has also been issued by MetService for the Coromandel from Sunday evening to Monday afternoon, with up to 150mm of water expected. A heavy rain watch has also been declared for the wider Auckland region during the same period, with rainfall expected to approach warning criteria.
In a tweet, MetService cautioned that heavy rain in Northland "may cause streams and rivers to rise rapidly", with possible surface flooding, slips and hazardous driving conditions.
Yet the much-needed rain will be welcomed by the drought-stricken region as Northland farmers continue to grapple with the fallout of a particularly dry summer.
On Saturday, the Auckland Civil Defence Emergency Management warned "we're expecting heavy rain and strong wind tomorrow and Monday" across the north.
However, the "giant high" expanding to New Zealand's east will spell sunny but frosty weather in the South Island, Duncan says, with some light rainfall expected in the island's north on Monday.
