There's a drastic interruption to summer on the way, in the form of gale force winds, snow flurries and waves up to 12 metres high

The first of two Southern Ocean storms will be making itself known today.

Snow flurries will arrive in the Fiordland National Park and both Christchurch and Wellington are in line for 100 kilometre an hour winds.

Head forecaster at WeatherWatch Philip Duncan says the sudden unseasonal temperature drop will come as a shock.