A severe thunderstorm watch has been issued for Christchurch, Canterbury Plains, and North Otago, effective until to 8pm on Saturday.

Metservice said the watch warns of scattered heavy showers and thunderstorms expected through the afternoon and early evening, with some storms potentially becoming severe.

According to the forecast, a few thunderstorms may produce hail with a diameter exceeding 2 cm.

Meteorologists advised that thunderstorm activity is expected to gradually ease from the south as the evening progresses.

The potential for large hail brings a risk of significant damage to crops, orchards, and vehicles, and may also pose hazards for driving.

The alert was issued at 1:18pm on 2 November, with the next update scheduled for 8pm.