Thunderstorms, rain on way

The Metservice has issued a watch for heavy rain and possible thunderstorms for the ranges of Westland south of Otira and Fiordland north of Doubtful Sound, from 5am to 5pm today. The watch says rainfall amounts may approach warning criteria. It also says an unstable northwest flow with embedded fronts will spread over New Zealand during today and tomorrow, bringing periods of heavy rain and possible thunderstorms to many places throughout the country.