The deep south had a stunningly sunny day yesterday, as evidenced by footage from the International Space Station as it passed over.
Those clear skies are expected to continue today with much warmer temperatures, ranging from 20°C to 25°C.
However, a MetService spokesman said a front was expected to approach the South Island from the west tomorrow, then move across the South Island on Monday.
The front would be preceded by heavy rain for western areas, but the associated gale northwesterlies would raise temperatures to the low 20s over the weekend and into early next week.
A heavy rain warning has been issued for Fiordland between 8am tomorrow and 1pm on Monday, where up to 300mm is expected to fall.
"Heavy rain may cause streams and rivers to rise rapidly.
"Surface flooding and slips are also possible and driving conditions may be hazardous."
He said there was also a possibility of warning amounts of rain falling in the Otago headwaters on Monday.
Northwest gales were likely from 1am to 1pm tomorrow in Fiordland, Southland, Stewart Island and Clutha, and may approach severe gales in exposed places.
He urged residents to keep a close eye on updates to the forecast.
