Everything all at once: dangerous waves, gales, rain, snow

A wild and wintry weather system is predicted to bring ‘‘dangerous’’ swells up to 6 metres high onto the western coast of the country over coming days.

Severe gales, thunderstorms, snow to low levels and potentially dangerous levels of rain in some areas are also predicted, MetService says.

The forecaster has issued a ‘‘suite’’ of severe weather warnings and watches ahead of the blast, which is due to gradually move north from Fiordland, where rain was already falling yesterday.

MetService meteorologist Angus Hines said people would have to be ‘‘very careful’’ if they were near the coast in the next few days.

‘‘It is not unprecedented wave heights, there is nothing coming that we haven’t seen before, but it is right at the upper end of what size waves have hit these western coastlines. The largest waves will be out over slightly deeper water, just a little bit away from the country, but the waves that do reach the coast will be around 5m or 6m, something of that kind of scale, and potentially very damaging.’’

The waves would be at their peak late tomorrow.

Hines said the size of the system sitting south of New Zealand, and its ability to whip up winds, were causing the big barrels.

Once it made landfall, the system would also cause problems, he said. ‘‘We are getting a bit more of a wintry outbreak, you could call it, or the first one of the year, actually.’’

Overnight temperatures today could reach 0C in Christchurch and -1C in Wa¯ naka and Queenstown.

‘‘Thursday is going to be a windy day but still quite mild with strong northwesterlies, but on Friday that is going to swing around to that southerly southwesterly direction which has generated the swells.

‘‘Many places will get showers, and there is likely to be some hail and thunderstorms,’’ Hines said.

‘‘Higher parts of the South Island could get some snow as well.’’

Snow could fall to as low as 400m in southern parts of the South Island tomorrow or early on Saturday, Hines said.

Orange heavy rain warnings are in place for Westland about and south of Otira till 3pm today.

Severe weather watches are in place for rain in the headwaters of Canterbury and Otago lakes and rivers.