Wednesday and Friday see two surges of severe gales across New Zealand along with heavy western rain and heavy alpine snow.
WeatherWatch.co.nz says Wednesday will be peak cold for the nation this week but Friday/Saturday will see another wintry surge in Southland and the lower South Island.
GALES Gales on Wednesday will mainly impact the western North Island and Auckland with gusts 70 to 100km/h and some isolated locations in the west (like the Manukau Heads and Kaipara Harbour) may see gusts between 110 and 140m/h for a time on Tuesday afternoon.
Gales on Friday are further down the country, mostly impacting Central NZ (upper South Island and lower North Island). These winds may be stronger than Wednesday’s as they get funnelled through Cook Strait area. Gusts on the tops of the ranges may exceed 160km/h with 130km/h gusts lower down.
RAIN: The main cold front moves over NZ today bringing rain, then more surges of wet weather move in over the days ahead. The bulk of the heavy rain will be on the West Coast while eastern areas look drier.
SNOW: Heavy West Coast rain will turn to heavy snow in the mountains with over 1 metre likely to accumulate on the summits over the coming five days.
A few snow flurries – lighter and unlikely to settle – will be expected to low levels in Southland and Otago on Wednesday.
FULL DETAILS: A low and associated cold front pass over New Zealand from Tuesday to Wednesday to produce rain or snow and strong winds across much of New Zealand
West Coast of the South Island will receive additional 50-80 mm of total rainfall with heaviest amount of 100-120 mm across West Coast ranges.
As temperatures plunge on Wednesday behind the cold front, rain will turn to snow across large portions of the South Island (mostly above a few hundred metres) as well as high elevation parts of the North Island.
Snowfall amounts will reach 20-30 cm with isolated area of 50 cm across Southern Alps. Central Plateau will also receive 5-10 cm of snowfall from Tuesday night to Wednesday.
With regards to wind, damaging southwesterly winds behind the front will impact the North Island on Wednesday with gusts of 80-90 km/h common and locally 100 km/h in western areas. Auckland looks most exposed on Wednesday afternoon with some power cut potential.
Strong west to northwest winds will prevail over New Zealand from Thursday to Friday.
Rain and gusty winds will begin Thursday across the West Coast again, before expanding to much of New Zealand Friday.
Stormy weather will remain over the North Island and the upper South Island till Saturday as a cold front moves over the regions.
Heaviest hit will be West Coast of the South Island again with 100-150 mm of rainfall and 50-80 cm of snowfall from Thursday to Saturday. Also, portions of the North Island including Manawatu-Wanganuland Wellington will expect 50 mm of rainfall.
The next round of strong winds will be 120-140 km/h westerly or northwesterly gusts across the Central New Zealand from Thursday to Friday. The tops of the ranges may see gusts in excess of 160km/h for a time.
Temperatures will be up and down significantly for the coming several days. Particularly, notable is the nationwide cold change expected on Wednesday.