Dark clouds gather over the Wither Hills as the weather system approaches. Photo: William Woodworth
People are being warned to brace for wild weather as an unstable weather system approaches the region.
MetService New Zealand has issued a Severe Thunderstorm Watch for Marlborough from 2pm to 7pm today.
The front is expected to bring heavy showers, and thunderstorms with the possibility of hail measuring more than 2cm in diameter falling at times.
There is also a chance of a small tornado forming, MetService say.
Large hail can cause significant damage to crops, orchards, vines, glasshouses and vehicles, as well as make driving conditions hazardous.
Shower and thunderstorm activity should ease tonight.