A large trough is expected to move onto the country from the Tasman Sea during the day. A deep low within this trough should move towards the south of the South Island. Windy and wet conditions are likely in many places.

There is high confidence that rainfall warnings will be needed in Nelson, Tasman, western Marlborough, Buller and much of Westland. For southern Westland, the Grey District, the Canterbury high-country and southern inland Marlborough there is moderate confidence that warning amounts of rain will fall.

Later in the day, there is low confidence that northwest winds around the Marlborough Sounds and Wellington will reach warning strength.

The trough slowly moves to the east of the country during the day and a west to southwest flow spreads onto New Zealand.

There is high confidence that warning amounts of rain will continue to fall in Nelson, Tasman, Buller and western Marlborough during the morning. For the Grey and Westland Districts, as well as the Canterbury high-country there is moderate confidence that the warning will extend into the morning. There is low confidence that a rainfall warning will be needed for Fiordland. Heavy rain is also likely in parts of the North Island and there is moderate confidence that a warning will be needed for Mount Taranaki/Taranaki Mounga and low confidence for Northland, the central North Island, eastern Bay of Plenty and the Tararua Range.

There is moderate confidence that northwesterlies will reach warning strength about the Marlborough Sounds, Wellington and southern Wairarapa in the morning. About southern Taranaki and Whanganui, there is low confidence that the northwesterlies will need a warning. There is low confidence that west to southwest winds about Stewart Island and the southern coast of the South Island will reach warning strength later in the day.

A narrow ridge should move onto the country in the morning. Late in the day a low is expected to be approaching the South Island from the west.

There is low confidence that warning amounts of rain will fall about the eastern ranges of the Bay of Plenty during the morning.

A low is expected to move onto central New Zealand during the day. There is currently a lot of uncertainty about the track and depth of the low. There is the possibility of some heavy rain about the west of the South Island, but not enough certainty about whether, or where, rainfall warnings may be needed for anything to be highlighted on the chart at this stage.