MetService News Release

27 February 2017

Autumn on the calendar, summer in the skies

This week the calendar slides from summer to autumn and the big question is whether the weather will follow the seasons. Summer is characterised by high pressure over central New Zealand, blocking the country from incoming fronts, but the odd afternoon shower bubbling up inland. Generally in autumn the highs start to move north, and westerly winds open the door to fronts followed by cooler southwesterlies.

This summer, the highs have only just started to muscle in over the middle of the country, which led to the sunny Saturday experienced country wide. Low cloud trapped under the high can still lead to murky conditions though, as eastern areas saw especially on Sunday. The good news is that the high pressures are here to stay for the week and any rainfall is most likely to be convective, as opposed to frontal. For more information on how convective showers form go to http%3A%2F%2Fblog.metservice.com%2FConvection.

“Convective precipitation spans the range from light afternoon showers to thunderstorms, hail and localised downpours”, said meteorologist Tom Adams. “There is a moderate chance of thunderstorms over the central and eastern ranges of the North Island for much of the week, with showers spreading out towards the coast. Otherwise, aside from scrappy cloud and mist stuck under the ridge, New Zealand is looking calm and sunny through to Friday”.

This pressure map shows high pressure over the country late Tuesday afternoon, but convective showers bubbling up in the central and eastern North Island.

Temperatures will remain at comfortable levels and with light winds and afternoon sea breezes, there will be plenty of opportunities to hit the beach. This pattern continues until late on Friday, when the high weakens and a front followed by cooler southwesterlies start to move up from the south.

Official Severe Weather Watches and Warnings are reviewed and re-issued by MetService at least every twelve hours, and more often if necessary. To get the most up to date information on severe weather around the country, or any other forecasts, see metservice.com or on mobile devices at m.metservice.com. You can also follow our updates on MetService TV, at MetService New Zealand on Facebook, @metservice and @MetServiceWARN on Twitter and at blog.metservice.com

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