A number of cold fronts are moving up the country today, bringing periods of rain and possible thunderstorms to Canterbury.
A "moderate risk" of thunderstorms is forecast for areas of Canterbury near the Southern Alps, Otago, Fiordland and Westland.
"A low risk of thunderstorms extends further north to Buller in the morning and about coastal parts of Southland," a MetService spokesman said.
In other parts of New Zealand, a moderate risk of thunderstorms is on the cards for those north of the Glaciers, Buller and western Nelson.
Those thunderstorms could spread to the Horowhenua, Kāpiti Coast, Taranaki, Waitomo and Waikato on Friday night.
And anyone in North Otago and South Canterbury will need a raincoat this afternoon and evening - with thunderstorms expected later on Friday.
"In both these areas, any thunderstorm activity will be mainly near the coast," MetService said.
"There is also a lower risk of thunderstorms during the afternoon and evening about Westland south of the Glaciers, Fiordland, Southland, Clutha and Dunedin.
MetService said a cold front over Fiordland and southern Westland this morning is set to move north overnight.
People in those areas are being told to be prepared for a period of rain and localised thunderstorms to western parts as a result.
Colder temperatures are also expected in some areas. While Friday will see the mercury climb to 23 deg C in Christchurch, it is set to plummet on Saturday with a high of just 12 deg C in the city.
The risk of thunderstorms is heightened later this evening and tonight in the lower western parts of the North Island; which could see heavy rainfalls of between 10 to 22mm/h, hail and gusts of up to 90km/h.
The place to be is Gisborne and Hawke's Bay - where it is mainly fine today. Wairarapa and Wellington are also the same, but a few showers are expected tomorrow before clearing in the afternoon or evening.
A high of 18 deg C is forecast for the capital city today.
Strong wind watch
A strong wind watch is in place in the Wairarapa area from 2pm to 11pm today.
MetService says northwesterly winds are likely to affect many exposed parts of the country - the strongest winds forecast in Wairarapa.
"People are advised to keep up-to-date with forecasts in case further areas are added or the watch is upgraded to a warning," the alert said.
Another severe weather update will be issued at 9pm as a result.
