On Friday and Saturday, the front was expected to remain slow moving over central New Zealand, but gradually weaken while a new low develops west of the South Island. Temperatures are set to plummet to the low-to-mid teens as the front moves through the South Island today and tomorrow. The remainder of the North Island will be mainly fine with just a few isolated showers. The cold southerly front will push over most of the South Island today and make it as far north as Taranaki by tomorrow. These swells will be accompanied by an easterly flow moving over the North Island.

Source: Otago Daily Times March 20, 2018 19:41 UTC