Most places have forecast maximum temperatures in the low to mid-20s, and parts of Central Otago are set to reach 25degC today and on Thursday.
MetService meteorologist Alwyn Bakker said the continuing settled weather meant east coast parts of Canterbury and Otago were becoming extremely dry.
‘‘Other than the odd convective shower, that’s set to continue for a few more days.
‘‘The mostly fine weather won’t last, however.
‘‘A low-pressure system is set to move across the South Island on Friday, bringing periods of rain to much of the country this weekend.’’
Mr Bakker warned the higher temperatures brought an increased risk of thunderstorms across the region on Friday and Sunday.
‘‘When the atmosphere is warmer and wetter at low levels than at higher levels, it’s unstable.
‘‘That means a small trigger, like converging winds, can make all that warm, moist air rise quickly and spark up a thunderstorm.’’
If a severe thunderstorm formed, he said there could be localised downpours of 25mm-40mm an hour, as well as hail.
Temperatures were expected to fall to the mid-teens on Saturday and Sunday.
