A front in the Tasman Sea feeds onto the West Coast of the South Island on Friday, pushing northwards during the day to reach the lower North Island later in the evening / overnight. Winds ahead of the front blow from the north and change southwest in behind.
For the North Island, in the west we see cloud increasing from morning and the odd shower possible from afternoon. Later in the evening / overnight is when rain moves in Taranaki southwards. The east coast during the day sees morning low cloud clear about Gisborne, otherwise expect mainly sunny weather with some high cloud developing from evening. Overnight rain moves into the Wairarapa.
For the West Coast of the South Island we see rain with potentially heavy falls pushing northwards along the coast during the day. The East Coast is mainly dry with thick high cloud, and perhaps a spot of rain about Otago in the morning then Canterbury / Marlborough afternoon and evening respectively.
A few further showers about Southland and Otago mid to late afternoon as a southwest change moves through. These showers move into Canterbury overnight.
– Aaron Wilkinson, WeatherWatch.co.nz