Rain & Colder Southwesterlies this Week: 9th - 12th June 2015

[NZLW]

A front should move over the South Island during Tuesday and early Wednesday. A very strong, moist, northwest flow is expected ahead of the front with should bring heavy rain to the west of the South Island and southern North Island and gale northwesterlies to the east of the South Island, Wellington and Wairarapa. A Severe Weather Warning and Watch are already in place for this event.

There is high confidence that warning amounts of rain will continue into Tuesday for Fiordland and Westland. On Wednesday there is high confidence that a rainfall warning will be needed in Westland, Buller and northwest Nelson. During the same period there is a high risk of warning amounts of rain spilling over into the headwaters of the Otago and Canterbury lakes and rivers.

The front should weaken as it moves onto the North Island but there is still a moderate risk that a rainfall warning will be needed for the Tararua Range,Mount Taranaki and about Tongariro National Park during Wednesday and Thursday.

For eastern areas there is moderate confidence that wind warnings will be required, covering Southland and Otago on Tuesday, Canterbury and Marlborough on Tuesday and Wednesday and Wellington, Wairarapa and parts of Central Hawkes Bay from Tuesday to Thursday.

Behind the front, colder southwesterlies should spread onto the country. A second front is expected to move over the south of the South Island late Wednesday or early Thursday and this could bring snow to low levels. There is low confidence that snow accumulations below 500 metres will warrant a warning for Thursday in Otago and Southland.

A trough is likely to bring some more heavy rain to Fiordland on Friday and there is a low risk that a rainfall warning will be needed there on Friday.

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[NZLW]

Amendment to warning - commencement of severe gales in Wellington and Wairarapa changed to this afternoon.
ISSUED BY MetService AT 11:34 am 09-Jun-2015

A strong to gale northwest flow covers southern and central New Zealand ahead of an active front, which is forecast to move onto the South Island this afternoon then the North Island during Wednesday. The front should bring rain to the west of southern and central New Zealand during this time, with the heaviest falls in Fiordland, Westland and the Alps. Heavy rain is currently falling in Fiordland and southern Westland, with another 150mm possible about the south Westland ranges and 70 to 100mm about Fiordland, the Otago Headwaters, and the south Westland coast, before the rain eases. About remaining parts of Westland and the Canterbury Headwaters, 200 to 250mm may accumulate about the ranges, with 100 to 150mm possible about the headwaters.

Heavy rain may cause streams and rivers to rise rapidly, with surface flooding and slips possible.

In addition, severe northwest gales are expected about Southland, Otago and Canterbury today, especially about inland areas, gusting 130km/h in exposed places. These severe gales are expected to spread over Marlborough, Wellington and Wairarapa today, eventually easing during Wednesday afternoon.