A large area of low pressure is expected to rapidly develop during Friday and Saturday then move across the North Island bringing torrential rain and possibly severe gales for some regions.

Because of the size of the low, and its slow movement, the low is likely to pass across northern New Zealand from Sunday to Tuesday bringing heavy rain to most northern and eastern parts of the North Island.

MetService is also closely watching the computer models and this afternoon issued a “high confidence” level in their Severe Weather Outlook for heavy rain from eastern Coromandel to southern Hawkes Bay on Sunday and Monday. They have ‘moderate’ confidence for Northland and Great Barrier Island.

High air pressure over the South Island looks set to intensify winds over central New Zealand with WeatherWatch.co.nz head weather analyst Philip Duncan saying eastern parts of Manawatu and Horowhenua would be particularly exposed.  “It’s a strange angle for gales in those regions…even relatively mild gale force winds can cause damage”.

Mr Duncan says the low is going to tap in to moist air from the sub-tropics.  “It’s definitely goodbye frosts for the north with this low moving in.  Northerlies will see overnight lows jump by as much as 14 degrees in some northern centres on Sunday night compared to this week”.

WeatherWatch.co.nz says heavy rain could cause rivers and streams to flood, especially in regions that will be most exposed to prolonged heavy rain.  “We’ll need to wait another 24 to 48 hours to be more specific but at this stage Coromandel Peninsula, Bay of Plenty, East Cape and Gisborne will be most exposed to the rain”.

Ski conditions in the Central North Island don’t look ideal for this weekend however Saturday may not be a write off.  “The latest weather data shows only a 10% chance of showers on Saturday morning around Mt Ruapehu…however that does lift to 70% later in the day.  Hopefully any showers will hold off until after dark”.

WeatherWatch.co.nz will have regular updates across the weekend and we want to hear from you too!  Post comments and send us photos of weather conditions where you are.