A high pressure system over the Tasman Sea is expected to have migrated eastward, crossing over the South Island for the next two or three days.
From Thursday, as the North Island lies behind this belt of high pressure, we can expect rain, showers and maybe even thunderstorms here and there, mostly the upper half of the island.
Winds from the easterly quarter will also increase – making for choppy seas and blustery conditions in some coastal areas.
Saturday, a sub-tropical low will appear and move southward, bringing locally heavy downpours and strong gusty winds in the North Island. Rain heads to the South Island by Sunday.
– WeatherWatch.co.nz (an official IBM business partner)