KEY POINTS:
Conditions improved as the working week came to an end across New Zealand this week but our weekend and next week are looking quite the opposite. A spring storm is developing out in the Tasman Sea and will impact the weather across the country in a number of ways.
Firstly, the size of this system - it's pretty big. Low air pressure will engulf much of the Tasman Sea over the weekend. This means most of the country will be impacted by the system - positively and negatively! If you're sailor, definitely avoid sailing this weekend and into next week - very strong winds and big seas between us and Australia.
The centre of this system looks likely to sit in the lower Tasman and the air pressure could drop below 980hPa - which isn't major but enough to make the seas pretty rough - especially for Aussie's south east coast.
Secondly, rain - this system is sucking moisture down from the northern Tasman so that means it'll be wet in a number of areas. At this stage there's a big of question mark over northern New Zealand but certainly the West Coast is in for a drenching and that may also affect the Tararua Ranges, Mt Taranaki and western areas of Central Plateau to Waitomo.
If a secondary low forms in the central or northern Tasman that could also drag in heavier rain for Auckland, Northland, Coromandel, Bay of Plenty and western/northern parts of East Cape - definitely one to watch.
Thirdly, wind - plenty of wind is expected from this system. Again there's a question mark as to how severe. I'm not seeing anything really major at this point but the nor'westers over eastern areas of both islands will be enough to drive the mercury up into the late 20s even early 30s from roughly Otago to Gisborne. These regions will be having another summer-like weekend with mostly sunny skies and hot days!
Northern New Zealand will also have high humidity so while temperatures will be in the lower maybe mid 20s the humidity will make things feel warmer. Overnight lows on Sunday across northern New Zealand may not drop below 17 degrees - so it could be a warm one.
The spring storm - a Spring Soaker as I'm calling it - will move into western regions of the South Island over the weekend then into northern New Zealand during Sunday or Monday.
Next week sees a westerly change then a cooler sou'west change as the week progresses. Across the weekend the Weather Watch Centre will increase its updates so be sure to check in regularly.
Philip Duncan
Pictured above: Afternoon strollers walk along the beach at Onetangi on Waiheke island before the rain clouds roll in. Photo / Babiche Martens.
For the latest weather news keep up to date with The Radio Network's new Weather Watch Centre or the NZ Herald weather section.
