A ridge of high pressure forecast to move over the country will keep any significant weather systems at bay until Friday.

This is according to the latest weather update from the MetService.

Conditions during the week will be ripe for afternoon convection, with showers forming in many inland areas during the afternoons, says a statement from the weather organisation.

Some of these showers are expected to develop into thunderstorms, especially about the central and southern North Island.

"A ridge of high pressure over the country this week brings light winds to many places, which will allow sea breezes to develop during the daytime," says MetService meteorologist Peter Little.

"Where these sea breezes converge with light winds from another direction it will force the air to be directed upwards, resulting in cloud build-ups, showers and potentially thunderstorms.

"Converging winds alone don't always lead to the development of showers and thunderstorms. There also needs to be enough warmth and moisture near the surface, and cooler than normal temperatures in the upper atmosphere, which makes conditions unstable."

Keep an eye on the daily Thunderstorm Outlook forecast to see if your area is at risk.

Temperatures across the country are forecast to be above average this week, with inland places away from the moderating effect of the sea expected to be warmest.

"'Inland parts of both islands are expected to see daytime temperatures peaking in the mid-twenties. Even Wellington's Hutt Valley is forecast to reach 26°C on Tuesday," says Peter,

On Friday, a large low-pressure system should approach the country from the Tasman Sea.

This large low will be preceded by a strong north to northeast wind flow and is forecast to bring rain to much of northern and central New Zealand.

"At this stage our Severe Weather Outlook has a few risk areas for Warning amounts of heavy rain around Mount Taranaki and the northwest of the South Island on Friday."