Weather: Hot temperatures, but heavy rain for some

Temperatures are expected be warmer over the next few days. Photo / File

Temperatures are starting to heat up and will stay warm for many parts of the country over the next few days.

But some areas are in for heavy rain and possibly worse - thunderstorms and hail - as severe weather warnings and watches have been issued.

MetService has put out heavy rain warnings for Westland, Fiordland and the Otago headwaters later this evening, lasting through to tomorrow morning. Between 120mm and 160mm of rain is expected to fall about the ranges in Westland, the same in the Tararua Range, and between 200mm and 250mm of rainfall about the ranges of northwest Nelson.

There is also a heavy rain warning over the Tararua Range, Buller and the ranges of northwest Nelson from tomorrow through to Tuesday.

The warm air flow has kicked in across the South Island. #Southland low 20s, #Canterbury low 20s also, mid 20s poss. Still increasing. pic.twitter.com/UdUzL3sCLb

— WeatherWatch.co.nz (@WeatherWatchNZ) September 23, 2017

Severe wind warnings have also been issued for Canterbury, Otago, Fiordland, Southland and Stewart Island tonight.

MetService meteorologist April Clark said weather conditions would be unsettled in the short-term thanks to an active front which would bring warm and moist air moving north from the South Island and over the middle part of the country.

"The warm air originated from the recently sweltering eastern coasts of Australia,'' she said.

"Though by the time it reaches our shores, it will have greatly cooled as it picks up moisture from the Tasman Sea."

Despite that drop, temperatures are still forecast to be high for a few days, particularly in eastern parts of the country.

In Napier, for example, the high is forecast at 25C tomorrow.

Temperatures are already hitting the late teens to early 20s-mark in the South Island today, with Christchurch sitting at a 23C high, 22C in Dunedin and the same in Invercargill.

WeatherWatch also shows temperatures in the North Island are sitting on the mid to late teens.

"However, the strong, warm northwesterlies ahead of the front mean rain for the western region, with heavy falls and thunderstorms forecast for those across the entire South Island's west.''

Clark said the fast-moving fronts - accompanied by strong winds and rain - would affect both the North and South islands with "some regularity'' right up to summer.

Things are heating up in the east of the South Island already with Cooptown on 24C & Blenheim/Ashburton close behind with 23C ^AC pic.twitter.com/NQypVEK2iE

— MetService (@MetService) September 24, 2017

MONDAY FORECAST:

- Auckland: 20C high, morning low cloud breaking, then fine
- Kaitaia: 19C high, sunny spells, cloud increasing in evening
- Whangarei: 23C, sunny spells, cloud increasing in evening
- Gisborne: 23C, a warm day. High cloud from evening
- New Plymouth: 16C, occasional drizzle turning to rain in evening
- Wellington: 15C, occasional rain developing morning
- Nelson: 17C, rain developing in morning, chance heavy
- Christchurch: 23C, fine with high cloud. Northwesterlies strong and gusty in morning
- Dunedin: 21C, fine apart from brief morning rain. Strong winds in morning
- Queenstown: 17C, period of morning rain then fine
- Invercargill: 17C, period of morning rain then fine. Strong in the morning