'Bomb' low crossing North Island Saturday 3 March
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For today's weather discussion head to: New Zealand Weather & Climate
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Re: Deep low crossing North Island Saturday 3 March
Met Service has issued the first warnings now
severe gales for central and southern NI, gusts to 150kmh!
severe gales for central and southern NI, gusts to 150kmh!
- TonyT
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Re: Deep low crossing North Island Saturday 3 March
As I've said before on this forum, "weather bomb" isnt even a technical term at all. I believe its origin can be traced back to a quote (which may even have been a misquote) from Bob McDavitt. The actual term used by the authors of the original paper (Sanders and Gyakum, 1980 see here http://journals.ametsoc.org/doi/abs/10. ... .0.CO%3B2) which I read back in 1981 soon after it was published was "bomb cyclone" or "bomb low". At the time the McDavitt quote first appeared I thought that perhaps Bob had mis-remembered the term, or the reporter had misquoted, it, or maybe Bob did decide to coin the term "weather bomb" deliberately.Philip Duncan wrote:Good morning all
Weather bomb is a term we don't use lightly
That paper also defined "explosive cyclogenesis" for the first time, which is also a good word to use for these systems as it conveys some sense of the dynamics of the system - ie what makes these systems so hazardous is not their size or their depth (central pressure) but the rate at which the central pressure is dropping, in the same way that the truly impressive thing about a seriously fast car is not the top speed it reaches, but the acceleration it has to get there.
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Re: Deep low crossing North Island Saturday 3 March
I'm a bit surprised Waikato has a warning but not Auckland, I wouldn't mind breaking my high wind gust recordManukau heads obs wrote:Met Service has issued the first warnings now
severe gales for central and southern NI, gusts to 150kmh!
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Re: Deep low crossing North Island Saturday 3 March
the auckland area will get hit hard too,dont you worry, thats my prediction
especialy if the low crosses the center of the NI
due to the wind flow being blocked by ranges, etc, it will want to find an easier route, which is through the narrow auckland region
especialy if the low crosses the center of the NI
due to the wind flow being blocked by ranges, etc, it will want to find an easier route, which is through the narrow auckland region
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Re: Deep low crossing North Island Saturday 3 March
M/S have a watch in place for severe gale SW winds on saturday for northland and auckland now
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Re: Deep low crossing North Island Saturday 3 March
Hmm... Clicking on that link, I just get 'The requested article is not currently available on this site'?TonyT wrote: As I've said before on this forum, "weather bomb" isnt even a technical term at all. I believe its origin can be traced back to a quote (which may even have been a misquote) from Bob McDavitt. The actual term used by the authors of the original paper (Sanders and Gyakum, 1980 see here http://journals.ametsoc.org/doi/abs/10. ... .0.CO%3B2) which I read back in 1981 soon after it was published was "bomb cyclone" or "bomb low". At the time the McDavitt quote first appeared I thought that perhaps Bob had mis-remembered the term, or the reporter had misquoted, it, or maybe Bob did decide to coin the term "weather bomb" deliberately.
That paper also defined "explosive cyclogenesis" for the first time, which is also a good word to use for these systems as it conveys some sense of the dynamics of the system - ie what makes these systems so hazardous is not their size or their depth (central pressure) but the rate at which the central pressure is dropping, in the same way that the truly impressive thing about a seriously fast car is not the top speed it reaches, but the acceleration it has to get there.
May have even been Erick Brenstrum who popularised the term 'bomb' here in a National Geographic story about 20 years ago, according to this 16 minute Radio NZ interview back in August, 2008 (fast forward 11 minutes).
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Re: Deep low crossing North Island Saturday 3 March
Try this, you can only see the abstract, I think the rest is behind a paywall.
http://journals.ametsoc.org/doi/abs/10. ... 2.0.CO%3B2
http://journals.ametsoc.org/doi/abs/10. ... 2.0.CO%3B2
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Re: Deep low crossing North Island Saturday 3 March
Hey Tony - yes I'm aware that technically the term isn't "weather bomb" - that term is simply jargon for bombogenesis - but Bob made it far more user friendly for the public and media.
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Re: Deep low crossing North Island Saturday 3 March
I've deleted a couple of posts which did not help further the discussion of the subject at hand. Please stay on topic, and if you wish to debate adversarially with other forum members take it to PMs.
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Re: Deep low crossing North Island Saturday 3 March
Barometer starting to fall here already
its not much to look at on the sat image at the moment
I guess the jet stream is hiding it
talked to someone who flew from melbourne to auckland...really bumpy flight!
its not much to look at on the sat image at the moment
I guess the jet stream is hiding it
talked to someone who flew from melbourne to auckland...really bumpy flight!
Last edited by Manukau heads obs on Fri 02/03/2012 12:58, edited 1 time in total.
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Re: Deep low crossing North Island Saturday 3 March
My weather station has the pressure down 1.8 hPa since 10am - when are we likely to see the rapid descent which could give it "weather bomb" status? (a term I really like, by the way, regardless of its technical validity )
Edited to add: Snap, Brian!
Edited to add: Snap, Brian!
Claire
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Re: Deep low crossing North Island Saturday 3 March
Flying into Wellington at 10.30am tomorrow morning, suppose the airport will close with gusts to 150kph??
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Re: Deep low crossing North Island Saturday 3 March
Taranaki will see the biggest pressure drop.....
the strong winds will be associated with the big pressure drop
thats expected to be overnight
you can see the jet stream is starting to kink in the tasman sea now
so thats the start of the cyclogensis
the thing about this system is its going to peak right over the NI
often system peak before they reach NZ...
the strong winds will be associated with the big pressure drop
thats expected to be overnight
you can see the jet stream is starting to kink in the tasman sea now
so thats the start of the cyclogensis
the thing about this system is its going to peak right over the NI
often system peak before they reach NZ...
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Re: Deep low crossing North Island Saturday 3 March
picture of where I think the low center is now
which if its moving east, has it crossing North Taranaki
which if its moving east, has it crossing North Taranaki
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Re: Deep low crossing North Island Saturday 3 March
Forecast:
*** STORM WARNING IN FORCE ***
Westerly 15 knots. Tending northerly 25 knots this evening, then rising to 50 knots overnight. Changing westerly 70 knots but 45 knots north of Raglan Harbour early morning,easing to southwest 45 knots everywhere Saturday afternoon, then easing to southwest 30 knots Saturday night. Sea becoming Phenomenal in the south for a time. Northwest swell rising to 5 metres for a time.Southwest swell rising to 4 metres. Poor visibility in rain developing this afternoon,very poor visibility for a time overnight,then poor visibility in showers Saturday.
Haven't seen this before! Seas becoming "phenomenal"
*** STORM WARNING IN FORCE ***
Westerly 15 knots. Tending northerly 25 knots this evening, then rising to 50 knots overnight. Changing westerly 70 knots but 45 knots north of Raglan Harbour early morning,easing to southwest 45 knots everywhere Saturday afternoon, then easing to southwest 30 knots Saturday night. Sea becoming Phenomenal in the south for a time. Northwest swell rising to 5 metres for a time.Southwest swell rising to 4 metres. Poor visibility in rain developing this afternoon,very poor visibility for a time overnight,then poor visibility in showers Saturday.
Haven't seen this before! Seas becoming "phenomenal"
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Re: Deep low crossing North Island Saturday 3 March
WOW
70 knot westerly expected for southern Raglan marine area?
thats insane
thats average windspeeds
never seen that forecasted before!
70 knot westerly expected for southern Raglan marine area?
thats insane
thats average windspeeds
never seen that forecasted before!
- littleheaven
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Re: Deep low crossing North Island Saturday 3 March
Another fantastic term! I must say I've never seen it on a forecast either.dan wrote:Haven't seen this before! Seas becoming "phenomenal"
Barometer still dropping here.
Claire
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Re: Deep low crossing North Island Saturday 3 March
I recall seeing this in the marine forecast for Cyclone Fergus in 1996, I think it means sea swell 14m ond over.dan wrote: Haven't seen this before! Seas becoming "phenomenal"
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Re: Deep low crossing North Island Saturday 3 March
sea waves I think you mean
as there is not time for the actual swell to reach that height (the swell forecast is only 5 m)
i.e short period waves (i.e like chop) on top of the ground swell.....accentuating the existing swell that is there....which can make waves as big as 14m (i.e an individual wave and not a group of swells)
as there is not time for the actual swell to reach that height (the swell forecast is only 5 m)
i.e short period waves (i.e like chop) on top of the ground swell.....accentuating the existing swell that is there....which can make waves as big as 14m (i.e an individual wave and not a group of swells)
- littleheaven
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Re: Deep low crossing North Island Saturday 3 March
Ah, yes, Wiki agrees. It appears to be the highest rating in the WMO Sea State Code. You learn something new every day.spwill wrote:I recall seeing this in the marine forecast for Cyclone Fergus in 1996, I think it means sea swell 14m ond over.
Claire
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Re: Deep low crossing North Island Saturday 3 March
I will most likely stare at my weather station when the wind gets going
I see that Metservice are expecting the low's central pressure to drop to 970hpa! Havnt had a low that deep for a while.....
I see that Metservice are expecting the low's central pressure to drop to 970hpa! Havnt had a low that deep for a while.....
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Re: Deep low crossing North Island Saturday 3 March
Tornado Tim wrote: I see that Metservice are expecting the low's central pressure to drop to 970hpa! Havnt had a low that deep for a while.....
Well not over the NorthIsland, except for a few close TC's moving past.
Shame we will miss the action down here, but then after the non-weather related natural events of the past 2 years , we don't really need a storm like that to come through. I hope there will no deaths or serious injury.
JohnGaul
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Re: Deep low crossing North Island Saturday 3 March
Not sure if we are getting spillover rain here or a southerly flick but it has been raining intermittently since lunchtime
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Re: Deep low crossing North Island Saturday 3 March
Last night and todays model runs have brought the low slightly further south, which means top of the south and perhaps even down to into Canterbury will get some brief nasty weather from it.
Persistant rain from early morning with gale SE winds maybe around 70-80kmh in exposed places, always hit and miss with these type of systems sometimes they track away from where models depict so the next 24 hours will be interesting.
Wesport will be a place to watch for again 150kmh plus gusts, i remember a simular system location few years ago in february giving the northern west coast a battering.
It is bomb status so to speak but i think its over rated in terms of how its being put across from the media, 970hpa is deep but we have seen deeper in the past.
There is a fine line between warning the public over a wide area and being calm about the situation as it happens, but i guess as government forecaster you have to cover all basis and protect or warn the public the best you can.
Persistant rain from early morning with gale SE winds maybe around 70-80kmh in exposed places, always hit and miss with these type of systems sometimes they track away from where models depict so the next 24 hours will be interesting.
Wesport will be a place to watch for again 150kmh plus gusts, i remember a simular system location few years ago in february giving the northern west coast a battering.
It is bomb status so to speak but i think its over rated in terms of how its being put across from the media, 970hpa is deep but we have seen deeper in the past.
There is a fine line between warning the public over a wide area and being calm about the situation as it happens, but i guess as government forecaster you have to cover all basis and protect or warn the public the best you can.
Canterbury, home of good rugby and severe storms