South Island weather: Heavy snow, rain watches for Otago, Southland - MetService

The first heavy snow watches have been issued for parts of Southland and Otago ahead of what’s expected to be the “most widespread snow [event]” so far this winter.

The wintry wallop, which is also expected to bring almost a day’s heavy rain to eastern Otago, is due to an incoming southerly, with the first effects likely to be felt from Monday afternoon.

MetService this morning issued a heavy snow watch from 3pm on Monday to 6am on Tuesday for inland areas of Otago and Southland, including eastern Fiordland.

“[The forecast is] a period of heavy snow above 500 metres, where snowfall amounts may approach warning criteria.”

There was a moderate chance the watch would be upgraded to a warning, the national weather service’s website advised.

People on Christchurch's Port Hills had a chance to perfect their snowball-throwing game last year - from Monday it will be the turn of those in Southland and Otago. Photo / George Heard

A heavy rain watch has also been issued for eastern Otago from noon on Monday to 6am on Tuesday, with a high chance this would be upgraded to a warning, MetService wrote.

“Streams and rivers may rise rapidly. Surface flooding, slips and difficult driving conditions possible … avoid low-lying areas and drive cautiously.”

A previously-issued heavy rain watch also remains in place for Fiordland, from Resolution Sound south, until 8pm tonight.

💦❄ Heavy rain and snow down south

🔁 After today's rain eases in Fiordland, the next bout of active weather for NZ comes on Monday/Tuesday.

🟡🌧 A Heavy Rain Watch has been issued for eastern Otago from Monday afternoon. (high chance of upgrade to Orange Warning)

🟡🌨 A… pic.twitter.com/j6d5GVGEam

— MetService (@MetService) July 27, 2024

Note the evolution to a clockwise 🔃 spin or circulation.

This is cyclogenesis: the development or strengthening of low pressure.

This will result in rain 🌧️ for the western/lower South Island this weekend.

Thereafter, things get more active... and interesting. pic.twitter.com/i156AVQyUL

— NIWA Weather (@NiwaWeather) July 26, 2024

Wet Fiordland aside, the rest of the country is today enjoying settled, mild weather, with high pressure over the North Island and a northwesterly windflow keeping temperatures unseasonably warm in some parts of the eastern South Island.

Banks Peninsula was the warmest place in the country just before 12.30pm, with a temperature of 21C, according to MetService’s website.

Ashburton also reached 19.1C early this afternoon. The July average in nearby Christchurch for July is around 11C.

Yesterday, Invercargill smashed its July high temperature record by almost 2C, reaching 18.6C at the airport for the first time since records began in 1948.

🤔 It gets colder the further towards the poles you go ... right?

🌏 Well yes, it generally does on average, since sunlight is more intense nearer the equator. But there's a lottttt of factors that contribute to temperature that vary every day and muddle things up!

☁ Take the… pic.twitter.com/o62C1n2EsD

— MetService (@MetService) July 26, 2024

Snow expected to fall in some Central Otago townships

Another fine day is expected for most parts of New Zealand tomorrow, apart from the South Island’s West Coast, where rain is forecast.

But the looming southerly will soon spell the end of the golden weather for much of the rest of the mainland.

The Southern Ocean stinger will bring not only a risk of heavy snow above 500m in the deep south, but lighter falls elsewhere, MetService meteorologist Lewis Ferris said late yesterday.

“I would expect snow to fall lower than that to some of the townships around Central Otago.”

Later falls could move north to parts of inland Canterbury, Ferris said.

“It’s the kind of stuff we see with snow this time of year, but this looks as though it could be the most widespread snow we’ve had in the winter so far.”

It could be hazardous on the roads in some parts of the South Island from Monday, with heavy snow and rain forecast. Pictured is State Highway 73 in Canterbury's Porters Pass during a snow event earlier this winter. Photo / George Heard

Heavy rain expected in other eastern parts of the South Island could also cause headaches.

“[Those] are areas that don’t get a lot of rain. So even though the amount of rainfall isn’t maybe as large as we’ll see in other places, it does still look like it could be impactful for the first half of the working week.”

The upper South Island and most of the North Island were expected to escape the worst of the foul weather, although heavy rain was possible around Mt Taranaki and eastern Bay of Plenty overnight Monday, Ferris said.

Cherie Howie is an Auckland-based reporter who joined the Herald in 2011. She has been a journalist for more than 20 years and specialises in general news and features.