While windy and warm temperatures are expected for eastern parts of both islands on Sunday, a very wet day is in store for the west and south.

A slow moving frontal system will track north across the Mainland on Sunday.  That will combine with plenty of moisture coming on shore from Tasman Sea to produce a lot of rain for the western parts of both islands as well as the deep south.

WeatherWatch.co.nz Forecaster Howard Joseph says the heaviest rain is expected fall about the western South Island tomorrow.

Mr Joseph says “During the pre-dawn hours, the heavy rain will likely be confined south of Westland.  But by sunrise, the heavy rain should spread north and affect both Westland and Nelson.”

There is also a possibility for heavy rain for the lower North Island early tomorrow.  Mr Joseph adds that some pockets of heavy rain may show up around Wellington and the Kapiti coast.  But the chances are small.

During the morning and into the afternoon, rain is forecast to be found about Nelson, Taranaki, Wanganui, south Waikato, the Kapiti Coast and Wellington.  But the chances for heavy rain will have diminished.

Mr Joseph says “That means that widespread heavy rain is not as likely, but pockets of heavy rain are still possible.”

By evening, the rain will likely cover most of the western North Island, from Auckland south to Taranaki.  The threat for heavy rain in these areas will be small.

-WeatherWatch.co.nz