In true Autumn style the big picture weatherwise around New Zealand this week is a bit of “everything off the menu, thanks”. Put simply we’re between high pressure zones – one is exiting, a cold front comes in – then the next one moves in.

Monday: High pressure is centred over the top of the Chatham Islands and brings easterlies into northern NZ. It will be dry or mostly dry across NZ but a few isolated showers are possible in the coastal east of the top of the North Island, and then also West Coast in the South Island. Mild west to north west winds develop across parts of the lower South Island.

Tuesday: A low pressure system with sub-tropical connections deepens just to the north east of New Zealand as high pressure continues to track away eastwards from us. The next high pressure zone is centred over the Great Australian Bight and so this far away placement allows more room for the low near NZ to deepen. At this stage this small offshore storm is likely to remain mostly offshore – but those in the north and east of the North Island should be monitoring it because there is always some chance it could move closer to land. This set up will generally make many parts of NZ milder than usual for the last day of April.

Wednesday: May 1st. Reliable modelling shows the north-eastern low drifting eastwards away from NZ as a colder southerly moves up the South Island bringing snow to the mountains and ranges and a temperature drop of several degrees for much of the South Island. Rain moves up the South Island and into the lower North Island bringing the temperature change. Showers turn to rain later in the day for the lower half of the North Island.

Thursday: The North Island gets a cooler change, colder in the lower half of the island. Some wet weather moves in. The upper North Island is least affected but will get another burst of showery sou’westers off the Tasman Sea. The South Island is mostly settled but Southland is still in the showery flow.

Friday: Sou’west flow moves over the country in true Autumn style. High pressure is centred south of Adelaide but a new area of high pressure will bubble up over the Chatham Islands and NZ area too, courtesy of the cool air that moved in before it.

Big Picture: A low with sub-tropical connections is deepening near East Cape, but the main feature for NZ this week is another cold front that brings true Autumn weather to the South Island & then falls apart over the North Island.

Full details in our lunchtime weather video. pic.twitter.com/pKOm6OKpyW

— WeatherWatch.co.nz (@WeatherWatchNZ) April 28, 2024

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