NZ Weather Forum

Parts of the South Island are expected to be quite unstable this afternoon and early evening due to the combination of cold temperatures aloft, warm conditions at the surface, light winds, and a southerly wind change moving northwards over the southern South Island. This will produce scattered heavy showers and thunderstorms over parts of the South Island today.

There is a moderate or high risk of thunderstorms this afternoon and early evening about Canterbury, North Otago, eastern parts of Central Otago, and Dunedin, with the highest risk of thunderstorms about Canterbury this afternoon. These thunderstorms will produce localised heavy rain of 10-20mm/h, and hail mainly in the 5-20mm diameter range. There is also a low risk of a small tornado and/or funnel cloud.

About Canterbury however, where the risk of thunderstorms is higher, some of the storms may be squally with wind gusts to 80km/h, and there is also a low risk a few of the storms could be severe with damaging hail larger than 20mm diameter. Hail of this size can cause damage to crops, orchards and glass houses etc, and make driving conditions hazardous. The risk of a small tornado may also be slightly higher in Canterbury. MetService forecasters will monitor the situation, and people within Canterbury should keep up to date in case any Severe Thunderstorm Watches or Warnings are issued today.

There is also a moderate risk of a few thunderstorms about the ranges of Westland early this afternoon, and a low risk over the remainder of Westland this morning and afternoon. Any thunderstorms that occur here will bring brief heavy rain and small hail.

NZ Thunderstorm Soc wrote: ↑Sat 04/11/2023 14:32 Thunder now all around us here in Geraldine.