A tropically-fuelled cocktail of muggy conditions, coupled with heavy rain and strong winds is set to sweep over New Zealand this weekend, threatening travel disruption and flooding.
MetService today issued a raft of warnings for the West Coast and bottom of the North Island, ahead of a sub-tropical jetstream taking aim at the country.
The forecaster says both islands are in for an unsettled period of weather from today onwards, with thunderstorms, heavy rain, strong winds, high humidity and hot temperatures.
Western and northern parts especially are in line for summer-like warmth and sticky conditions, with humid air warm fuelling a spell of "active weather" featuring electrical storms.
Strong winds bearing down on Wellington on Saturday could affect travel, while heavy rain could see regions inundated by slips and flooding.
Temperatures are expected to rise on Friday, with unusually warm weather expected this weekend and into next week.
Over coming days the tropical airflow would see humidity increase, with Niwa advising those in the north to get out the fans.
The timing couldn't be worse for the Women's Rugby World Cup, with Auckland and Whangārei both set for a wet weekend. When the Black Ferns kick off on Saturday night at the Northland Events Centre in Whangārei it is likely to be a sticky 23degC and showery.
Niwa said a sub-tropical jetstream would fuel strong fronts in the flood-ravaged West Coast. The rain was expected to start falling in Westland from Thursday night until late on Friday afternoon.
MetService said up to 160mm of rain was expected in the ranges, with a second period of rain likely during Saturday.
Buller is expecting a similar level of rain with a warning issued for 26 hours of non-stop rain from Friday lunchtime.
The forecaster warned the heavy rain might cause streams and rivers to rise rapidly and pose a threat of flooding.
The Tasman District Council warned residents on Thursday afternoon to get prepared. While the burst of rain is not expected to be a large event, now was a good time to make sure everything was in order.
The Nelson region was inundated in August with days of rain that saw rivers burst banks, and widespread damage to homes and surrounding terrain.
