Damaging hurricane force winds of over 200km/h roared across Auckland last night but did weather forecasters see it coming? The answer is both yes and no.

Last night MetService did have a warning in place for Auckland for 120km/h winds while WeatherWatch.co.nz earlier in the day (2pm) had specifically warned both the public and Vector Energy of incoming power cuts from gales and that some trees would come down. Our forecast was that damaging winds were likely in the evening then easing in the early hours of Wednesday as the southerly change swept in.

So yes, forecasters did know strong gales, potentially damaging, were coming.

However no, the actual forecasts did not talk of such strong and damaging winds getting to hurricane force and up around the 200km/h mark. So why were the winds so strong? WeatherWatch.co.nz head forecaster Philip Duncan says there were a number of moving parts. “We had a deepening low moving in from the Tasman Sea, we then had that low making landfall in Waikato and brushing South Auckland which then placed the strongest winds directly over Auckland City itself. To help keep the energy the powerful nationwide Antarctic southerly was roaring up behind it fuelling more winds. Finally, on top of all that, these worst winds then tracked across Auckland via a natural wind tunnel. All of that combined created damaging gales that were a notch above the forecasts”.

Mr Duncan says the area of damaging winds was relatively small but just happened to be placed over our largest city with 1.5 million people. “Waikato to the south wasn’t very badly affected and neither was Northland just up the road, so it was really the wind tunnel effect through Auckland coupled with a deepening low making landfall that helped ramp up these gales even further”.

WeatherWatch.co.nz says the low has weakened and the worst winds have passed but strong gusts from the south will continue today off and on.

10:15pm #UPDATE for #Auckland: In the big scheme of things the damaging winds hitting Auckland right now are a small speck on the overall wind map, but these gales are now fully crossing the region and that means some may already notice peak gusts easing back a little before 12AM pic.twitter.com/eTSkle2Xxh

— WeatherWatch.co.nz (@WeatherWatchNZ) April 10, 2018

8:35pm #Update: The centre of a low is making landfall in the western North Island (Waikato to South Auckland). Much cooler S to SW winds develop tonight behind the centre spreading over northern NZ. Winds peak between now and the early hours of Weds AM at this stage. pic.twitter.com/EmnrmaXY2s

— WeatherWatch.co.nz (@WeatherWatchNZ) April 10, 2018

– Image / The set up around 9pm Tuesday evening as the low came in with the windy change wrapped around the centre.

– WeatherWatch.co.nz