'Bomb' low crossing North Island Saturday 3 March

[NZstorm]

With a period of heavy rain and gales for many North Island places.

looks like warm frontal rain moves onto the North Island Friday evening and the deepening low moves across Saturday morning.

[Richard]

I see the models showing it crossing more to the south this morning than it was showing yesterday,look like crossing lower North Island but that may change again over the next day or so yet.

[Michael]

They tell Auckland southerly forecast,doubt it given its position another repeat of SW

[jamie]

Could be a windy day on saturday at you place Brian by the looks. I have an outdoor wedding in auckland on Saturday. Poor guys are pretty stressed about the forcast.

[spwill]

I have an outdoor wedding in auckland on Saturday. Poor guys are pretty stressed about the forcast.

The clearing process will be rapid on Saturday, they could luck a reasonable afternoon but at this stage you would say blustery with showers Sat afternoon, Sunday certainly much better.

[Manukau heads obs]

keeping a close eye on this low with interest

[David]

Check out the strong wording on the Metservice severe weather watch...

RAPIDLY DEEPENING LOW EXPECTED TO CROSS NORTH ISLAND SATURDAY WITH
DESTRUCTIVE GALES AND HEAVY RAIN. ALSO, WESTERLY GALES IN HAWKES BAY
MAY BECOME SEVERE FOR A TIME TODAY.

MetService forecasters expect a low to deepen rapdily as it crosses
the Tasman Sea on Friday, and to become intense as it crosses the
North Island on Saturday. Gale force winds are expected over much of
the North Island for a time on Saturday. In some places, these gales
could be severe and damaging. A period of very heavy rain is also
expected in many places.

People in the North Island, particularly those planning outdoor
activities, are urged to keep up to date with the latest forecasts as
warnings will be issued closer to the event.

[Manukau heads obs]

WOW
been a while since we have had such a strong system move over like what is being predicted

[Richard]

Yes that word DESTRUCTIVE

[jamie]

marine is for 40kt winds. wonder what the gusts are then?

[Manukau heads obs]

that is just the initial marine forecast
that will be changed, most likely up

[Philip Duncan]

We're going with the "weather bomb" headline I think with this one... most models I've looked at show it deepening 24hPa in 24 hours... although a couple are a bit borderline if it will happen in 24 hours not, so just waiting for another update or two.

[jamie]

yes latest raglan forcast (auckland still not out) has winds rising to 55kts (102km/hr) on Saturday. Thats crazy!!!

Genarlly speaking, if thats for sustained winds, what % higher than sustained winds do gusts get to? ie could there be gusts 70+ knots out there on saturday?

[Manukau heads obs]

yup , 70 knot gusts for Raglan could be on the cards

[spike_01]

Yes that word DESTRUCTIVE

Yeah I got that email..

Took particular note of that word.. Dont think I have seen it used before an event arrives..

[David]

At this stage, it looks like the strongest winds will be from the SW for Auckland. The gusts could get quite high especially if there are squalls embedded (not sure if there will be though)

[NZstorm]

Chart here for 9pm Friday with developing low showing a classic warm sector.

[BeaconHill]

Might be a good day to take down the shade sail tomorrow me thinks

[Michael]

Should blow some pine cones this way then,have had sizable twigs in some of the earlier years especially around the early 2000s.

At this stage, it looks like the strongest winds will be from the SW for Auckland. The gusts could get quite high especially if there are squalls embedded (not sure if there will be though)

[melja]

I see weatherwatch are doing sensationalist journalism again with this one, calling it a "weather bomb" using the word cyclone in storys and even in the questions part liking it to a cat 1 even 2 cyclone one part in this mornings story says they can form eyes like cyclones. very poor form.

[spike_01]

I see weatherwatch are doing sensationalist journalism again with this one, calling it a "weather bomb" using the word cyclone in storys and even in the questions part liking it to a cat 1 even 2 cyclone one part in this mornings story says they can form eyes like cyclones. very poor form.

I tend to agree with them..

If this was coming down from the warm Pacific it would be called a TC..

[melja]

No i dont think it would, nothing like a cyclone structure! no warm air core its cold.

[Manukau heads obs]

yes, its got nothing in common with a TC
(except the potential windspeeds and damage from that)

its actualy a classic wave depression , you can see it now on the sat image mid tasman
the fact its going to deepen very quickly, and possibly deepen 24 hpa in 24 hours, does it give it weather bomb status

[Nev]

melja, even MetService say that it has the potential to become a 'weather bomb'. I don't think the story's sensationalist at all, quite the opposite. It's actually quite informative, explains what a 'weather bomb' is and goes on to explain how it differs from a 'cyclone'. Nowhere does it suggest that it can form an eye like a cyclone.

Edit: Just read their 'Friday national forecast', "They can even form "eyes" like a tropical cyclone, with calm weather in the middle". Ok could have been worded a little better, e.g. '...what look like eyes...'

[Philip Duncan]

Good morning all
Thanks guys - and just to explain to melja

Weather bomb is a term we don't use lightly - infact this may even be the first or second time in several years that we've used it.

With regards to a cyclone - we were asked by a reader if the Category ratings can be used to measure these storms - we said they have an entirely different structure - one is warm, one is cold - but that, roughly, you can use the Category ratings to some degree - then explained the differences betweem cyclones and storms that form in the Tasman Sea. Our severe forecaster, Howard Joseph, also mentioned in an update that the centre of a weather bomb can be similar to the eye of a cyclone - in that it can be calm, but we pointed out that if we were using the US hurricane categories this wouldn't even be Cat1. Hardly sensational!

Phil