Southland and Otago would have the most sunshine in the country today with clear skies and fine conditions predicted.
"They're set for some pretty warm weather for the next couple of days," Adams said.
Dunedin was expected to reach temperatures of up to 26 and 27 degrees on Sunday and Monday, while Invercargill scorchers of 28 degrees today and 31 degrees on Monday and Tuesday were expected.
Also expecting dire weather is the central Plateau where there is a moderate risk of severe thunderstorms including large hail, 15mm in diameter, and lots of rain- between 25 and 45mm per hour.
The thunderstorms would be very localised.
It's a continuation of poor conditions which saw Rotorua residents experience flash flooding amid heavy rain yesterday.
In one hour 25 mm of rain fell in that area, alongside 200 lightening strikes.
MetService said the most lightening strikes were recorded in Gisborne and the Hawke's Bay, which registered 1722.
Meanwhile in Auckland, the warm weather is expected to continue with the odd patch of cloud.
Temperatures would reach up to 26 degrees over the weekend, ahead of a wet Tuesday and Wednesday.