The South Island is in for heavy rain and strong winds this week, with the MetService issuing several warnings.

A front is expected to move northwards over Fiordland today and become slow moving in Westland during Wednesday and Thursday, according to the MetService.

They said that a humid north to northwest flow precedes the front, and is expected to bring periods of heavy rain to Fiordland and Westland, and strong north to northwest winds to Fiordland and the Canterbury High Country.

Watches and warnings are in force for heavy rain and severe gales. This is expected to be a significant heavy rain event for Westland, with potential for an upgrade to a Red Warning over the coming days. However, there is some uncertainty with the movement of this front, and the placement of heaviest rain may change, the MerService said.

People are advised to keep up to date with the latest forecasts.

MetService meteorologist Mmathapelo Makgabutlane said, “The ranges of the Westland District south of Hokitika, which are under an Orange Warning, can expect rainfall amounts of 600 mm to 800 mm between Tuesday and Thursday, with lesser amounts near the coast.”

“This is a significant heavy rain event, and we will be keeping a close eye on developments over the next 24 hours as there is the potential to upgrade to a Red Warning. Rain of this amount may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous,” Makgabutlane said.

Other areas in the South Island are also under Orange Warning or Watch, which may be upgraded in the coming days.

The rain extends northwards to the top of the South Island from Thursday and onto the North Island Thursday into Friday.

“While it’s still early days, there is the potential for Heavy Rain for places like Tasman, as well as the central North Island. In fact, the whole northern half of the North Island, including Auckland and Northland could be in line for a period of heavier falls as the system moves through on Friday,” Makgabutlane said.

The system also spreads rain eastwards to potentially affect Southland, Otago and Canterbury by the end of the working week.

“This is an evolving situation and is a large weather system with a widespread reach. Anywhere under a Watch, Warning, or highlighted in the Severe Weather Outlook should brace for a wet few days,” they said.

“Wherever you are in Aotearoa New Zealand this week, be sure to keep an eye on the weather, as this system will affect all parts of the country to varying degrees.”