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Potential Tasman Sea “weather bomb” later this week

Computer models have been picking for days a rapidly forming low in the Tasman Sea this Thursday, Friday and Saturday which may become defined as a “weather bomb” says

The term “weather bomb” relates specifically to a low pressure system that drops 24hPa in 24 hours.  “It’s the weather equivalent of having a tyre blow out” says head weather analyst Philip Duncan.  “The air pressure plummets and conditions quickly become unstable”.

Some media outlets incorrectly use the weather bomb term to describe any stormy weather however it should only be used to describe this rapid deepening of a low pressure system. 

Weather bombs in New Zealand tend to cause isolated but severe damage.  A weather bomb in Patea, South Taranaki, back in March caused extensive damage as hurricane force winds blew out roofs, walls and toppled trees – however only slightly further north winds remained light.  “These weather bombs tends to have the severe gales, or hurricane force winds, right near the centre, just like tropical cyclones. So the further away from the centre you are, the lighter the winds usually”.

So what are the chances of this low reaching this criteria?  Mr Duncan says fairly high at this stage. “The models we’re looking at show the air pressure dropping from around 1000hPa on Thursday evening to 976hPa on Friday morning, possibly lower”.

The low is expected to generate big seas on the western coastline, torrential rain for the West Coast and severe west to north west gales for eastern and central New Zealand.

“We still have to wait another day or two to confirm but no matter how you look at it, it seems likely a nasty low will develop in the Tasman Sea overnight Thursday and into Friday – then weaken across the weekend as it passes over New Zealand”. will monitor the low and bring you daily updates.



Colleen matthie on 22/06/2016 9:04am

Hi we are supposed to board the Pacific Pearl sailing from Auckland to Sydney tomorrow 23.6.2016

What should we expect? Am feeling rather nervous.

Thanks Colleen

WW Forecast Team on 22/06/2016 12:55pm

Hi there

In terms of swell conditions feel free to visit our free swell maps here:

Use the colour coded key to determine what the swell height will be, use the back and forward buttons to go further forward or back in terms of the time.

Likewise you can check out the potential wind speed here using the same method:

Otherwise best to contact your cruise company as they will have a better idea as to how the weather conditions will affect their ship.

– WW Team

Phil M on 15/09/2013 7:38am

We have a yacht Mid Tasman (500NM out of Sydney) heading for North Cape then Auckland. What sea conditions are expected over the next 3 days?

WW Forecast Team on 16/09/2013 1:46am

Hi there

Best bet is to go to our maps section and you can see there things like swell height, wind speed and the movement of weather systems.


Guest on 10/10/2012 11:00pm

I’m flying Auckland to Melbourne early Friday morning. How bumpy will my flight be? lol

WW Forecast Team on 11/10/2012 2:02am

Could be a bit bumby perhaps? I’m no expert on weather affects on flying conditions up high in the atmosphere but the Tasman Sea will be a mix of fronts and strong winds.


Glyn on 8/10/2012 5:28am

We’re flying out to China from Auckland on Friday night. Are we likely to be delayed or have very bad weather leaving NZ?

Thanks for your great website – always love reading all the articles.

WW Forecast Team on 8/10/2012 7:29am

Hi Glyn, firstly – thanks very much 🙂  Secondly, international flights are rarely affected by weather in Auckland – and most of the energy from this system will be in the southern Tasman Sea.  The low will actually start to weaken as it moves over New Zealand across Saturday/Sunday.  So at this stage Friday night should be ok for your flight.  Just keep an eye on our Auckland forecasts and feel free to ask for an update if you need it.  Have a great trip!


Guestrobert on 8/10/2012 4:37am

ohh darn not again south island and lower north get the big storms and yet again auckland will miss out i live in auckland and i love big storms how come we always miss the big storms if they come from the north they always go down the east if they come from the west they mostly hit south or lower north i feel like moving down the line a bit to get the big storm hehe i no we have had a bweather bomb before but i love them i no its werd lol

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