New Zealand is well known for its spectacular mountain ranges especially during the winter when they are covered in a fresh layer of snow. It is not usual to see that snow level dropping down below the mountains but when it does it can cause disruption to New Zealand’s public travel networks.
If you look back to the Towns & Cities forecast tabs or the Rural forecasts, you will notice that at the bottom of the 10 day forecasts is this phrase: “Forecasts and temperatures for days 1-5 are produced by MetService meteorologists. Forecasts and temperatures for days 6-10 are automatically generated by MetService's computer weather modelling system.”
Sitting out in the middle of the ocean, New Zealand is vulnerable to extremes of weather from all directions; from the remains of tropical systems barrelling in from the north, to cold winter southerlies bringing a blanket of snow.
As New Zealand’s designated national meteorological service to the World Meteorological Organisation (WMO), it is MetService's responsibility to provide clear, concise and timely warnings of severe weather that is likely to affect New Zealand.
What defines severe?
The story of summer 2012/13 was rain, or rather the lack of it. Drought was declared for the North of the country on the 27th February, shortly followed by the rest of the North Island and parts of the South Island. The prolonged dry spell was due to presence of large lingering areas of high pressure that dominated the weather across New Zealand. These areas of high pressure acted as blocks, sitting over the country while areas of low pressure, and their associated rainfall, skirted either side of the country.