SEVERE WEATHER WARNING.
ISSUED BY MetService AT 8:48pm 05-Mar-2015
URGENT - IMMEDIATE BROADCAST IN: Nelson, Buller, Canterbury, Taranaki
BURST OF HEAVY RAIN EXPECTED ABOUT WESTLAND AND THE ALPS, NORTHWEST
NELSON RANGES, AND MOUNT TARANAKI ON FRIDAY
An active front, preceded by a strong moist northerly flow, is
expected to move rapidly east over the South Island during Friday
morning, then the North Island in the afternoon and early evening. A
period of heavy rain is expected with this front, especially about
Westland and the Alps, where hourly rainfalls could reach 25 to
40mm/hr for a time in thunderstorms. Rainfall accumulations could
approach 180mm about the Westland ranges and Alps in a 9 to 12 hour
period, with 100mm expected about remaining parts of Westland,
including the Paparoa Range, Canterbury Headwaters, northwest Nelson
ranges and Mt Taranaki.
This is a significant amount of rain over a short period of time;
streams and rivers could rise very rapidly, with surface flooding and
hazardous driving conditions.
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HEAVY RAIN WARNING
AREA/S AFFECTED: WESTLAND, INCLUDING THE PAPAROA RANGE
Rain is expected to become heavy from tonight (Thursday to Friday).
In the 12 hours from midnight tonight to midday Friday, expect 70 to
100mm to accumulate north of Haast, but 120 to 180mm about the
ranges. Peak intensities of 25 to 40mm/hr in thunderstorms during
FREEZING LEVEL: About 3400 metres lowering to 2400 metres Friday
AREA/S AFFECTED: NORTHWEST NELSON RANGES
Northerly rain is expected to become heavy Friday morning. In the 6
hours from 8am to 2pm Friday expect 70 to 100mm to accumulate. Peak
intensities 20 to 30mm/hr in thunderstorms late Friday morning.
FREEZING LEVEL: 3400 metres lowering to 2800 metres early Friday
AREA/S AFFECTED: CANTERBURY HEADWATERS
Rain is expected to become heavy about the Alps Friday morning, with
significant spillover into the headwaters. In the 9 hours from 5am to
2pm Friday, expect 100 to 150mm to accumulate near the Divide, with
70 to 100mm within 30km east of the Divide. Peak intensities 20 to
30mm/h in thunderstorms near the Divide during Friday morning.
FREEZING LEVEL: About 3400 metres lowering to 2400 metres late
morning/early afternoon Friday.
AREA/S AFFECTED: MOUNT TARANAKI
Rain is expected to become heavy about the Mountain late Friday
morning. In the 6 hours from 10am to 4pm Friday, expect 70 to 100mm
to accumulate. Peak intensities 15 to 25mm/hr in thunderstorms Friday
NEXT SEVERE WEATHER WARNING WILL BE ISSUED AT OR BEFORE
9:00am Friday 06-Mar-2015
Forecast prepared by: Sarah Garlick
For further information after 9pm contact Duty Forecaster Gerard
Barrow or Matt Ford
A service provided through a contract with the Crown
Short Range Forecast
Northland to Taranaki, including Bay of Plenty and the central high country: Isolated showers turning to rain this afternoon, possibly thundery in Taranaki and Waitomo, then becoming confined to eastern Bay of Plenty this evening.
Wanganui to Wellington, also Wairarapa: Cloud increasing, and a period of rain this afternoon.
Gisborne and Hawkes Bay: Mainly fine, brief rain south of Hastings this evening.
Marlborough, Nelson, Buller, and Canterbury High Country: Heavy rain and northerly gales, with thunderstorms possible in the west. Rain clearing this afternoon and winds easing.
The remainder of Canterbury, also Otago and Southland: Scattered rain, clearing this afternoon then fine.
Westland and Fiordland: Rain, with heavy and possibly thundery falls, clearing this afternoon but heavy rain returning tonight.
Chatham Islands: Cloud increasing, and drizzle developing this evening.
Saturday: North Island, rain with some heavy falls from Taranaki to Wellington. Showers elsewhere, but only scattered falls in the east. Northerlies strengthening, gale in exposed places from Taranaki to Wellington. South Island, heavy rain in the west, but only scattered falls further east, followed by showers and southwesterlies.
Sunday: North Island, mainly fine. A few early showers for Wellington and Wairarapa. South Island, rain developing in the west. A few showers in the south. Cloudy periods elsewhere.
Monday: North Island, showers developing in the west from Taranaki to Wellington. Mainly fine elsewhere. South Island, a few showers about the ranges. Mainly fine elsewhere.
Chatham Islands: Cloudy periods. Drizzle, turning to rain late Saturday with northerlies, then showers and westerlies on Sunday and Monday.