A big low pressure system moves out of the Tasman Sea today with its centre passing over central New Zealand later this afternoon / evening. This low will usher in southerlies over the South Island and a northwest airflow for the North Island.

Northland, Auckland, Waikato & Bay Of Plenty
Showers, some rain for a time this afternoon about Auckland, Waikato and Bay Of Plenty. Easing back to showers this evening. Northerlies tend breezy northwest around midday.
Highs: 16-19

Western North Island (including Central North Island)
Rain, becoming heavy this morning then easing this evening. Thunderstorms are likely about Taranaki for a time. Northerly winds then changing southerly overnight.
Highs: 10-16

Eastern North Island
Some rain about Gisborne and Hawkes Bay spreads into the Wairarapa this afternoon, rain then becomes heavy about the Wairarapa and clears further north to let in some sun. Winds from the north, changing southerly about the Wairarapa this evening.
Highs: 13-17

Wellington
A few showers then rain develops this afternoon, heavy falls possible then easing later this evening. Northerlies change southerly this afternoon.
High: 13

Marlborough & Nelson
Mostly cloudy, rain develops this afternoon with heavy falls possible then clearing later this evening. Southerly winds freshen.
Highs: 11-14

Canterbury
Cloudy areas, south to southwesterly winds freshening from afternoon then showers move in this evening.
Highs: 8-10

West Coast
Chance of an early shower then expect sunny areas and some high cloud, southeasterly winds develop this afternoon.
Highs: 13-15

Southland & Otago
Mostly cloudy, there may be some sun at times this afternoon especially inland. Light winds tending southerly around midday, patchy showers or drizzle by evening.
Highs: 8-10

By Weather Analyst Aaron Wilkinson – WeatherWatch.co.nz