Dunedin dodged a bullet on Tuesday morning, when forecasted heavy snow failed to show.

MetService meteorologist Alwyn Bakker said snow warnings were in place on Monday night and into Tuesday morning, which were expected to bring up to 5cm of snow to sea level and larger amounts about the hill suburbs.

Given the amount of disruption from road closures around Dunedin on Monday, and the forecast for even heavier snow overnight, the city’s roads would have been severely impacted had the forecast  been correct, he said.

However, the expected snow failed to happen because a “bubble” appeared over Dunedin, forcing the snowy weather to travel either side of the city, rather than over it.

“It turns out that there was just this beautiful dry slot that formed over Dunedin.

“You had showers going to the east of you and showers going to the right of you, and nothing in the middle.

“So that’s why you didn’t get any snow.”

He said the dry slot was caused by the fact the snow was coming from showers rather than persistent rain.

“If the snow is coming from rain, it’s much easier to say, ‘Yep, you’re definitely going to get snow.’

“But if the snow is coming from showers — showers can pop up over here or over there — it’s very difficult to pick where they are going to pop up.”

Mr Bakker said changes in wind direction also played a part.

“And it can also happen if there’s terrain blocking wind flow, like a large hill or a mountain or whatnot.

“I think that was broadly what was going on there in Dunedin.”

Depending on how you feel about it, you were either lucky, or unlucky, he said.

He believed Dunedin may have dodged a bullet because it would have been “quite bad” if it had happened.

The areas either side of the city received “a decent amount” of snow.

While the forecasted snow was not 100% guaranteed from the start, Mr Bakker said it was still important to warn people that it could happen, so they  were prepared.

“You’ve got to kind of hit that fine line. It’s better to be slightly too cautious, than not cautious enough.”

State Highway 87 between Middlemarch and Outram remained closed overnight but reopened about noon on Tuesday. 

The “weather whiplash” continues on Wednesday and Thursday, when temperatures up to 19˚C are expected in Dunedin, he said.

john.lewis@odt.co.nz