Key Points:

Parts of the country may be in for thunderstorms today, although wet weather will ease for some of the hardest-hit parts of the North Island. Gisborne and Hawke's Bay, which have been hammered by rain this week, should expect to see it easing off, MetService meteorologist April Clark said. Meanwhile, Taranaki, Waitomo, and Taihape were likely to experience thunderstorms. The South Island was becoming more unstable, and rain is expected inland, as well as some low cloud in Southland, she said. A massive storm that knocked out power to South Australia this week is expected to cause flooding and slips when it reaches New Zealand. The storm will have lost most of its impact by the time it arrives at the south of the country on Sunday. However, Weather Watch weather analyst Philip Duncan said any flooding would be localised. The storm would cause a big shift in the weather pattern the country had been experiencing this week. Easterlies have switched to westerlies, bringing a welcome reprieve to the drenched east coast, including the Coromandel Peninsula.

What to expect

"This week has been dominated by low pressure around the North Island, high pressure south of us and lots of easterlies," Duncan said. "Once Sunday arrives, the leftovers from the Australian storm reaches New Zealand. It swings our entire weather pattern to a westerly one - so it dumps all the heavy downpours on the west coast and makes the east coast the sunnier, drier, warmer place to be," he added. "So it's a good mix for the school holidays, it means one side gets it one week and the next side for the next week." Saturday will be the transition day for the arrival of the Australian storm, which will reach the west coast of the country on Sunday. "By Monday the wind flow across the country will be a gusty westerly and is feeding directly out of Australia, from Brisbane to Adelaide, so it's going to be even warmer." Despite the storm battering the country's eastern coast, very little had fallen in the much needed area of North Canterbury, Duncan said, with one resident emailing to tell him he'd received just 2mm. The prognosis was not good for the area for the rest of the week with the front now coming from the west, it was not expected to fall on the parched land. MetService meteorologist Derek Holland said the rain would start hitting the South Island's West Coast from Sunday. Westerly winds should follow the storm, allowing eastern areas to dry out after this week's miserable weather. The Fire Service in Auckland attended about 20 weather-related callouts yesterday, mostly for blocked drains.More than 200 lightning strikes were recorded from Northland to Taranaki between 3.30pm and 4.30pm yesterday.Kopu east was the wettest area overnight where 63mm fell in the 12 hours to 8am.

Today's forecast

Whangarei: Fine spells, chance afternoon shower. Light winds. High 20 Auckland: Showers, some possibly heavy in the afternoon. High 18C. Hamilton: Cloudy with showers, possibly heavy in the afternoon. High 17C Tauranga: Rain clearing in the morning. High. 17C Wellington: Fine breaks, chance evening shower. Light winds. High 17C Christchurch: Early cloud then fine spells, chance evening shower. High 16C Dunedin: Fine spells, late afternoon shower. High 15C Source: MetService