A significant spring storm is expected to hit the southern region early next week, bringing heavy rain and possibly some snow.
A MetService spokesman said a deepening low, and an active front preceded by strong and moist northwesterlies, were expected to approach New Zealand from the west on Sunday.
The low was forecast to cross southern New Zealand on Monday, then move slowly eastwards on Tuesday and Wednesday.
The front associated with the low was expected to move northeastwards over the South Island on Monday and the North Island during Tuesday morning.
Following the front, a very strong and cold southwest flow would spread over the country, and would persist until at least Wednesday.
"On Monday, there is high confidence rainfall amounts will reach warning criteria about Fiordland and Westland, especially about the ranges, with spillover into the headwaters of the Otago and Canterbury lakes and rivers also likely.
"For Southland and eastern parts of Otago, there is moderate confidence of heavy southerly rain on Monday and/or Tuesday.
"Snow will likely lower to around 500 metres in these regions on Tuesday, with heavy snow possible at higher elevations, likely affecting some roads and high country farms,’’ he said.
In addition, severe northwest gales were likely in exposed parts of the Canterbury High Country on Monday.
On Tuesday and Wednesday, it was possible severe south to southwest gales would affect exposed parts of southern Fiordland, coastal parts of Southland and Otago, and Banks Peninsula, he said.
