Rain, rain and more rain
The North Island can expect heavy rain over the next two days, with the chance of slips and surface flooding for eastern parts.
Coromandel, Bay of Plenty and Gisborne can expect heavy rain and thunderstorms throughout the day and into the night, which may cause streams and rivers to rise very quickly, as well as causing slips and surface flooding, MetService said.
It will be particularly heavy after 5pm, with Coromandel and Bay of Plenty expecting 100 to 150 millimetres of rain and Gisborne likely to see 80 to 120mm.
Rain intensity may reach 30mm/hr at times.
The rest of the North Island, as well as northeastern parts of the South Island, can also expect heavy downpours.
Northland, Auckland, Waikato, Waitomo, Taranaki, Taumarunui, Taihape and Taupo are in for a drenching, with the possibility rainfall may become heavy enough to warrant a severe weather warning this afternoon.
Rain is expected to be heavy at times from Wednesday night through to Thursday morning for Hawke's Bay, Wairarapa, Wellington and Marlborough.
The flow then turns to the south Thursday afternoon, bringing heavy rain for a time to Wellington and Wairarapa until Thursday evening.
The rest of the South Island is the place to be as it will avoid the majority of the heavy rain.