Another week and another big southerly blast is on the way, kicking off on Thursday and peaking Friday/Saturday across the country and producing dangerous seas.

The strong south west flow, which WeatherWatch.co.nz first forecast over a week ago, is still likely to come in on Thursday on the back heels of a large Tasman Sea low crossing the North Island tomorrow, Wednesday.

By Friday this cold south to south west change peaks over the country and the pressure gradient between a large high over Aussie and deep low pressure in the Southern Ocean means the ‘squash zone’ will help pump out some big waves, with WeatherWatch.co.nz saying they may well exceed 10 metres on the west coast.

Those in Auckland are advised to avoid fishing on the rocks in the west, or being out on the water in the west, over Thursday, Friday and Saturday due to gale force marine conditions and these enormous seas. Meanwhile boaties and fisherman are advised by WeatherWatch.co.nz not to use dangerous river bars or harbours later this week like Greymouth or Manukau – or really any western marine entrances to the Tasman Sea – from Thursday to Saturday due to the dangers.

– WeatherWatch.co.nz