Severe thunderstorms and heavy rain could occur in many areas of the North Island, MetService says.
Thunder and heavy rain warnings and watches cover many areas, including Wellington, Auckland, Northland, Great Barrier Island, Coromandel, Bay of Plenty and Rotorua, while there are also snowfall warnings for two main roads from the South Island.
Residents in Wellington and Wairarapa have been warned to stay indoors and away from windows, as severe thunderstorms are expected to hit the region.
MetService has issued a severe thunderstorm warning for Wellington City, Hutt City and South Wairarapa, after detecting severe storms near offshore Mana Island and near Wellington Airport.
The bad weather was expected to end near Wellington, Porirua, the Wellington South Coast, Palliser Bay and Baring Head, later moving south to the Remutaka Ranges.
Heavy rain and hail were also forecast, and residents are encouraged to stay home and check that drains are clear.
In the South Island, snowfall warnings were in force for State Highway 7 through Lewis Pass and State Highway 73 through Arthur’s Pass, until 8 p.m. and 9 p.m. respectively.
Meanwhile, MetService meteorologist Ngaire Wotherspoon said Northland, Auckland, Coromandel and the Bay of Plenty north of Gisborne should prepare for showers.
Forecasters have issued a watch advisory for the period from 6 p.m. Sunday to midnight, due to an unstable northwesterly airflow.
Snowfall of between 25 and 40 millimeters per hour is forecast, with a risk of hail and a low risk of tornadoes, she said.
Rainfall of this intensity could cause surface and/or flash flooding, particularly in low-lying areas such as streams, rivers or narrow valleys, and could also lead to landslides, the advisory states. MetService.
He urged people to plan ahead and be vigilant for changing or threatening conditions; and to stay informed of weather warnings.
“Traffic conditions will also be dangerous, with surface flooding and poor visibility in the event of heavy rain.”
The weather is expected to improve after 10 p.m. for northern areas.
Tips on how to prepare for a storm can be found here.