Half a metre of rain is predicted to fall in some parts of the South Island from a number of days of rain according to government forecaster MetService who today has issued 18 rain warnings for the country. 

Severe thunderstorms and damaging tornadoes are also in the forecast.

WeatherWatch.co.nz says a combination of the weekend’s low and a much bigger low in the Southern Ocean plus a blocking high to the east of the country means heavy rain along the West Coast won’t ease up.

The current weather pattern also means more humid nights in northern New Zealand and northerlies continuing in the South Island for the next 48 hours.

“Heavy, thundery rain should gradually ease overnight Monday [in Westland]. In the 24 hours hours from 9am today to 9am Tuesday, a further 150 to 200mm is likely about the ranges, with 100mm possible near the coast. However, another 300mm is possible about the ranges between Otira and Franz Josef, bringing totals here to 500mm since Saturday night” says MetService.

Rain warnings have also been issued for some western areas of the North Island

MetService is also warning west coasters that there’s a “high risk” of severe thunderstorms today and tonight which includes a high risk for damaging tornadoes.

The Lightning Detector at WeatherWatch.co.nz has already recorded over 8000 strikes today mostly offshore to the west.

To read all 18 rain warnings click here.