MetService has upgraded its severe weather watch for Otago to a warning as a weather bomb looks set to wipe out the sweltering heatwave tomorrow, even leaving parts of the South Island doused in snow.
The forecaster today upgraded the watch for Otago, Southland and other parts of New Zealand.
It is now predicting 80mm to 130mm, or possibly more, of rain to fall from 2am to midnight tomorrow in Otago, with peak intensities of 24mm to 40mm and hour.
In Southland 90mm to 130mm was expected to fall from 12am to 10pm tomorrow.
A strong wind watch has also now been issued for North Otago, Dunedin and Clutha from 2pm to 8pm tomorrow.
The unseasonable storm is also expected to bring snow to as low as 1000m in some areas just days after it reached 37.6C in Clyde - New Zealand's hottest January temperature in 14 years.
MetService today also issued a swathe of heavy rain and wind warnings across all of the South Island and bottom of the North Island for the coming two days.
The forecaster says the storm will come from the Category One Tropical Cyclone Fehi, which formed near New Caledonia earlier on Monday, and will smash into the South Island on Thursday and early Friday bringing heavy rain and gale-force winds up to 100km/h.
The heaviest rain is expected in Westland and Fiordland where 200mm to 400mm of rain could accumulate from tonight to early on Friday. Heavy rain is also expected for Mt Taranaki and Tararua Range.
The combination of strong winds, heavy swells and high tides could cause coastal inundation on the West Coast and Nelson on Thursday.
Snow expected at Cardrona
Snow is expected to fall on many of the South Island's skifields. Cardrona Alpine Resort marketing manager Nadia Ellis said the changing weather was "crazy".
"It is so unseasonable. From the extremes of 35C in Wanaka earlier this week, to snow predicted, makes it all very interesting.
"At Mt Cook they are predicting greater snowfall this week than at Whistler Blackcomb in Canada, which is in the middle of winter."
While MetService is predicting 8cm of snow to fall on the Cardrona Skifield tomorrow, Ellis says the continuing warm weather means it is unlikely to settle enough for people to be able to get on their skis and snowboards.
Over the summer months Cardrona opens up to mountain bikes and carts, which Ellis expects could make for some "interesting rides" in the snow.
Those in the South are being warned to watch for fast-rising rivers and streams and motorists are being told to be wary of flooding and slips in perilous driving conditions.
The Otago Regional Council said rivers could rise rapidly, with localised flooding possible in low-lying areas. Sediment run-off would also be an issue, particularly in the Queenstown Lakes area.
More blazing heat next week
Before the predicted storm hits from Wednesday night, temperatures are expected to climb into the 30s in Otago, including Dunedin.
Fire crews and helicopters are on standby in the province as the fire risk rises to the extreme level, the paper said. People have been advised to postpone machinery work that might generate a spark or heat.
But the storm would begin to pass and conditions would improve rapidly on Friday, and on Saturday a high was expected to spread over the South Island while the flow hanging over the North Island would drift Southeast
Places like Alexandra were expected to drop 20 degrees over the next 48 hours, Clark said.
"Alexandra is on 36C at the moment, then it could drop to 21C on Thursday then to 16C on Friday."
Tuesday marked another day of blazing heat, with the central South Island bearing the brunt of things as temperatures reached the high thirties.
Otago, again, was the centre for scorching temperatures as Clyde in Central Otago peaked at 37.6C, The National Institute of Water and Atmospheric Research reported.
It wasn't just humans that were in need of a cool one either. At Auckland Zoo, keeper Hayley Paul was cooling off one of the zoo's emus with a shower in the hot weather on Tuesday.
