Parts of Southland, the Lakes District and Central Otago are in for a major deluge later today.
A MetService spokesman said heavy rain and north-to-northwest gales were expected to hit central and southern parts of the country tonight and tomorrow, as an active front moves on to the South Island today, and tracks slowly north.
An Orange Heavy Rain Warning has been issued for the headwaters of Otago’s lakes and rivers between 2pm today and 6am tomorrow.
Up to 200mm of rain is expected about the main divide, and up to 150mm is expected within 20km farther east.
‘‘Peak rates of 15mm to 25mm per hour are expected on Thursday about the divide.
‘‘Freezing level will be about 2300 metres.’’
He urged those living near the lakes and rivers to be prepared for the deluge.
‘‘Streams and rivers may rise rapidly. Surface flooding, slips, and difficult driving conditions are possible.
‘‘Clear your drains and gutters to prepare for the heavy rain. Avoid low-lying areas and drive cautiously."
Fiordland (about and north of Doubtful Sound) was also under an Orange Heavy Rain Warning from noon today to 6am tomorrow.
Up to 170mm of rain, possibly more in localised areas, was expected to fall, and peak rates of up to 25mmh were expected this evening.
Thunderstorms were also possible tomorrow morning.
Westland District was expected to receive up to 210mm of rain between 6pm today and noon tomorrow, with peak rates of up to 30mmh.
During the same timeframe, the headwaters of the Canterbury lakes and rivers (about and south of Arthur's Pass), was expected to receive up to 210mm of rain about the main divide and up to 180mm within 20km farther east, he said.
He advised anyone living in these areas to keep up to date with the latest forecasts, in case some watches were upgraded to warnings, and more warnings and watches may be added.
