MetService has predicted severe thunderstorms for Dunedin, Port Chalmers, Warrington and Waitati from about 5pm.
These severe thunderstorms are moving towards the north, and are expected near Palmerston and Waikouaiti between 5pm and 5.30pm.
"Very heavy rain can cause surface and/or flash flooding about streams, gullies and urban areas, and make driving conditions extremely hazardous.
"Large hail can cause significant damage to crops, orchards, vines, glasshouses and vehicles, and make driving conditions hazardous."
Waikouaiti has already experienced hail today as pea-sized stones fell in the town from about 1.30pm, followed by heavy rain.
The National Emergency Management Agency advises that as storms approach you should:
- Take shelter, preferably indoors away from windows;
- Avoid sheltering under trees, if outside;
- Get back to land, if outdoors on the water;
- Move cars under cover or away from trees;
- Secure any loose objects around your property;
- Check that drains and gutters are clear;
- Be ready to slow down or stop, if driving.
During and after the storm, you should also:
- Beware of fallen trees and power lines;
- Avoid streams and drains as you may be swept away in flash flooding.
Earlier
MetService meteorologist Dan Corrigan said the weather would be cool but dry for most Anzac Day services around the regions tomorrow morning, but that would change in the evening.
He said the front would travel up the South Island during Sunday, bringing rain and a cool southwesterly in its wake.
Single-digit overnight temperatures were expected for most, dropping as low as -5degC for some places, bringing frosts and snow to inland and sheltered areas.
‘‘Later on, on Monday night, it looks like we could get snow flurries down to 800m in Central Otago and Northern Southland.
‘‘It looks like going into the working week next week, for inland parts of Otago, we could get some frosts, too.’’
He said the snow would give the surrounding hills and mountains a good dusting, but it was not expected to affect main routes through the region.
‘‘The only place affected will be the Crown Range Rd on Monday, where snow may lower to 900m.
‘‘We aren’t saying anything for the Lindis Pass road or the Milford road at this moment, but my advice would be to keep an eye on the forecast, in case there are any updates as we get closer to the time.’’
MetService also warned the public to take special care on, or near, beaches in western parts of the country over the long weekend.
A deep low in the Southern Ocean near the Antarctic is expected to generate sea swells that could reach 9 metres, between the far south and the West Coast tomorrow.
Heavy swells, with a very long period of 18-20 seconds, will affect the west coast, creating strong and dangerous rip currents, with high beach run up.
It could pose a threat to fishers, surfers and others, particularly on the South Island's West Coast, where it is also likely to exacerbate coastal erosion.
A rain band would move north,bringing a chance of thunderstorms.
The weather is expected to settle again on Tuesday as a ridge develops, allowing a westerly flow to spread over the lower South Island.
— additional reporting RNZ
