A storm moving in from Melbourne looks set to bring a rough end to the weekend and start to the working week with severe gales and heavy rain.

A large low, which developed over southern Australia overnight, will push out into the Tasman Sea during Saturday, then track south of New Zealand on Sunday and Monday.

Head weather analyst Philip Duncan says New Zealand will be right in the squash zone.  “With a large high to the north, with central air pressure up to 1035 hectopascals and a deep low to the south, around 975hPa, that will create a huge drop in air pressure over the country”.

Mr Duncan says on a weather map that means lots of isobars squashed together,  “Think of highs as mountains and lows as valleys and the isobars are like topographical lines – the tighter they are the steeper the slope – and in this case that slope is air pressure.  It will cause the wind to slide very quickly creating gales”.

While the centre of the low isn’t likely to cross New Zealand that should have very little difference on our weather as gales, possibly severe, spread into eastern and central areas and heavy rain moves up the west coast.

Graphic / NZ Govt

Image: Matthew Tyler