Covering period of Monday 17 - Thursday 20 March

A mosaic of Severe Weather Warnings and Watches cover the South Island, highlighting strong winds and heavy rain travelling up the South Island over today and tomorrow (Tuesday). Strong, warm northwesterly winds precede the band of rain, while cool southerly winds follow close behind.

Heavy Rain Warnings have been issued for the Westland District and Fiordland for only the second time this year, as these regions bear the brunt of the incoming rain.

MetService meteorologist Clare O’Connor details, “Up to 200mm of rain is expected in the ranges of Westland, and 100mm for areas nearer to the coast. These areas are well below their usual year to date rainfall totals, and surface flooding, slips, and adverse driving conditions are worth looking out for.”

A Heavy Rain Watch has also been issued for the Southland Region, including Stewart Island, with periods of heavy rain expected to affect the west of that region from Monday afternoon.

In the east of the South Island, temperatures are being pushed as high as 30°C as gusty northwesterly winds travel over the Southern Alps. The expected strength of these winds has resulted in Strong Wind Watches for the Canterbury High Country, Canterbury Plains, and the Otago and Southland Regions, with wind gusts of 100 km/h possible in those areas. An additional Strong Wind Watch covers Wellington from the early hours of Tuesday as the northwesterly winds arrive onto the lower North Island.

O’Connor adds, “These warm northwesterly winds will be quickly replaced by cooler southerlies behind the main band of rain, producing a bit of a rollercoaster in the temperature charts. Cricket fans in Dunedin on Tuesday will need to layer up, with only 15°C expected.”

“This switch in wind flow brings a chance of thunderstorms for the upper South Island and the North Island – excluding the regions in the east. While there are no severe thunderstorm watches in place right now, heavy showers and thunderstorms could be possible Tuesday afternoon and evening, so we advise checking in on our thunderstorm outlook.”

MetService’s Thunderstorm Outlook can be found here: http://bit.ly/TSOutlook

The last of the rain clears from the eastern South Island Wednesday morning as the rain moves northwards and high pressure settles over the South Island once again bringing fine weather. Conditions over the North Island are expected to remain showery throughout the week, with the wettest weather moving from west to east later in the week.

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