The reasonably settled conditions of the last few days look set to evaporate as a large low develops in the Tasman Sea, along with a surge of much colder air behind a front moving up the South Island.
MetService media and communications meteorologist Daniel Corbett said the next few days will be quite a shock to the system across some parts of the country.
“People will be grabbing the extra warm layers,” he said.
“Although it is not unusual for October, temperatures in the east of the South Island over the next few days are likely to be significantly colder than they have been in recent weeks.
“During today, heavy snow may fall to 500m in North Otago and mid-Canterbury and southeasterlies will develop.”
The forecast for tomorrow looks like following much the same pattern, with early rain turning to snow above 600m, before clearing and becoming fine.
Mr Corbett said these conditions were likely to be a “significant event” for parts of the South Island high country.
“Farmers in these areas should be aware that vulnerable stock may be at risk,” he said.
“Higher level roads may also be affected and conditions are likely to be hazardous for trampers.”
Oamaru will also be affected by the changeable weather conditions with rain today and Friday and showery conditions set for tomorrow and Thursday.