A big low pressure system moves out of the Tasman Sea on Monday with its centre passing over central New Zealand later in the afternoon / evening. This low will usher in southerlies over the South Island and a northwest airflow for the North Island.
One of the main features of this low wil be some heavy rain moving through about Auckland southwards from late morning then easing by evening. Taranaki in particular is looking likely to get heavy falls and thunderstorms then easing during the afternoon. Nelson and Marlborough in the South Island sees some heavy rain develop early afternoon also then easing in the evening.
The second main part of this low will be the drop in temperatures for the South Island later in the day. This more or less will be typical of a cold southwest in winter for the eastern South Island. Expect some snow for the ski fields and on other inland mountain ranges. Sea level snow is not looking to be in the equation.
So rug up for some unsettled weather early this coming week. A sub tropical low to the north of the country may be something to keep an eye on mid week for the North Island, at this stage heavy rain for Northland looks possible. Ridging brings mainly settled conditions to the South Island mid week onwards, this spreads onto the North Island later next week.
Image: Monday 18th June 2018 3:00pm MSLP / Rain map – weathermap.co.nz