Strong winds are in store for Wellington, Wairarapa and Hawke's Bay as a southerly front moves up the country "like a freight train".
Winds would continue to strengthen as the front approached from Canterbury, MetService meteorologist Daniel Corbett said.
"Active thunderstorms will form ahead of the southerly change, which will barrel up the east coast of the South Island like a freight train," he said.
The front would move through Christchurch tonight and Wellington about midnight.
"Wind gusts could get up to around 100kmh later today, early tonight," he said.
A weather watch had been issued in Hawke's Bay, Wairarapa and Canterbury, where gales were expected to become severe, gusting to 120kmh and easing early tomorrow.
Winds of this strength could damage trees and power lines and make driving difficult, especially for high-sided vehicles and motorcycles.
Temperatures were expected to drop after the front, Corbett said.
Wellington could expect a high of 21 degrees Celsius today and 15C tomorrow.
The outlook for the weekend was brighter, with an anticyclone expected to bring mostly fine and dry weather, he said.
- Fairfax Media