A changeable week of weather ahead

January 25, 2016

It was fine and hot for many across the country this weekend, with temperatures reaching the early 30s for some.  The weather stations at the Blenheim and Christchurch Airports recorded 32 degrees on Saturday, while Gisborne recorded 31 yesterday, although no records were broken.  It’s shaping up to be another hot one today, especially for the North Island.

However, a stationary front situated in the Far South has been bringing heavy rain to the West Coast, especially southern Westland and Fiordland, and scattered falls to Southland and Otago, with Milford Airport recording around 390 mm since midnight Friday. The rain in these areas is on an easing trend; although a further 100-200 mm is likely to accumulate about the ranges, and Severe Weather Warnings and Watches remain in force until Tuesday morning. Total accumulations of 500 mm or more in some places are expected from this event. “This is an exceptionally large amount of rain, even for these areas, and people are advised that rivers and streams will rise rapidly and slips and flash flooding are likely,” said MetService Meteorologist Ciaran Doolin.

Meanwhile, in the tropics, Tropical Cyclone Victor was reclassified as a Tropical Low overnight Friday. In the last 24 hours Victor has undergone a transition from a tropical to a mid-latitude low and is currently located approximately 150 km east of Raoul Island, and 1100 km northeast of Cape Reinga. From there it is expected to continue to track south-southwest and pass close to the northeast of the North Island on Wednesday.

Today should be mostly fine for the North Island, apart from isolated afternoon and evening showers in central and northern areas. The warm temperatures are looking set to continue, with a number of places in Gisborne, Hawke’s Bay and Wairarapa forecast to exceed 30 degrees. Meanwhile, the front that has been bringing heavy rain to the Far South is forecast to move slowly up the South Island, becoming stationary again near the top of the Island on Tuesday.

On Tuesday, the first band of moisture associated with Cyclone Victor spreads across the North Island bringing scattered showers to central and northern areas, while the stationary front keeps most of the South Island wet.

Then on Wednesday, Cyclone Victor is forecast to make its approach on the country and is expected to be northeast of Gisborne by midnight. “This system is forecast to bring rain to the east of the North Island and northeast of the South Island from Wednesday. Heavy falls are looking increasingly likely for Gisborne and Hawkes Bay, especially about the hills and ranges, where rainfall amounts may exceed warning criteria. However, the intensity of the system is still rather uncertain, and although it looks likely it will bring moderate swells and a period of south to southeast gales to eastern and southern parts of the North Island and north-eastern parts of the South Island, these forecasts may be subject to change,” Doolin explained.

As the working week comes to a close, Cyclone Victor is expected to track south of the east coast of the North Island on Thursday and the rain and winds are forecast to ease as the system moves off.  In the South Island, rain in the north is expected to ease overnight Thursday as the stationary front weakens. On Friday a body of warm, moist tropical is expected to produce isolated showers for central and northern areas of the North Island.

Official Severe Weather Watches and Warnings are reviewed and re-issued by MetService at least every twelve hours, and more often if necessary. To get the most up to date information on severe weather around the country, or any other forecasts, see metservice.com or on mobile devices at m.metservice.com. You can also follow our updates on MetService TV, at MetService New Zealand on Facebook, @metservice and @MetServiceWARN on Twitter and at blog.metservice.com

 

MetService issues Warnings, Watches and Outlooks for severe weather over New Zealand.

Warnings are about taking action when severe weather is imminent or is occurring. They are issued only when required.
Recommendation: ACT 

Watches are about being alert when severe weather is possible, but not sufficiently imminent or certain for a Warning to be issued. They are issued only when required.
Recommendation: BE READY 

Outlooks are about looking ahead, providing advance information on possible future Watches and/or Warnings. They are issued routinely once or twice a day.
Recommendation: PLAN 

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