New Zealand has a deep trough passing over the country over the next 48 hours with a wintry southerly roaring in behind it, bringing snow to near sea level in the south.
An area of low pressure has formed to the west of NZ and it is forecast to move eastwards and cross the country during Friday. During this event, locally heavy rain and possibly isolated thunderstorms are likely to cross the country.
More than 50mm of rain is expected around Kahurangi National Park today.
As the low continues to bring cold southerlies, precipitation (rain) is expected to turn into snow.
WeatherWatch.co.nz says snow levels may drop to just 100 or 200m, meaning some flurries may get very close to sea level in Southland/Otago. However mild soil temperatures at the moment means the snow will unlikely settle for long below 200m.
Snow may be heavy in Canterbury inland and through the highlands for a time with 20 to 50cm possible in the mountains and ranges.
The coldest day for the South Island is Friday. The coldest day for the North Island is Saturday. Snow will spread into the North Island late Friday and early Saturday to just 300m around Wellington and Wairarapa - may impact SH2. Snow may also fall on SH5 Napier to Taupo around the summit, or down to 500m.
Frosts return to Central Otago on Saturday - and may well be heavy with overnight lows tipped to drop as low as -3 or -4C in some inland areas.
Temperatures will dramatically change on Friday. Warmer than normal conditions, which have been dominate across the country so far, suddenly become 4C to 8C cooler/lower than normal. However next week, in true spring style, bounces back with those same areas getting snow on Friday possibly reaching 20 degrees next week.