Cyclone heads away

Will tropical cyclone Hamish hit New Zealand? There's been quite a bit of discussion around this and while animated satellite maps show the huge storm barrelling towards us, it's actually doing anything but that. In fact, it's now looking likely to do a U turn out at sea. Yesterday morning it was tracking south east - directly towards us - at 14km/h. During the day it had slowed to 11km/h. It will almost completely stop before turning E, NE and then possibly even N and NW over the remainder of the working week.

Hamish looked terrifying on Sunday when it was a Category 5 cyclone with it's magnificent eye. The eye of a cyclone (or hurricane in northern hemisphere) is a remarkable thing and we very rarely get the chance to see one so well defined on our 'local' satellite map. The winds are ferocious in the eye wall. Just like when you pull the plug from your bath the currents are stronger near the centre of the plug...the closer you are to the centre the faster and faster it spins. When you pull the plug the water often spins so fast you can see an 'eye' forming as water levels lower. It's spinning so fast clear air is appearing in the middle. The centre of a cyclone is the same...once a clear eye has formed the skies in the middle are usually mostly cloud free (or water free in our bath analogy). The wind is also calm. Nasa put out an image of Hamish yesterday NZT quite clearly showing the eye.

Hurricane hunters in America fly directly into these eyes and drop weather instruments into them to precisely measure conditions. I think I'm a storm chaser at heart...storms don't scare me too much...but the thought of flying through a category 5 cyclone freaks me out on a scale I can't even comprehend! The turbulence is bad enough flying into Wellington sometimes let alone a monster hurricane. There are some magnificent photos on the net of hurricane hunters flying inside an eye. This one was from Hurricane Katrina. Or just google image the words: hurricane hunter eye.

Tropical Cyclone Hamish has an uphill battle towards New Zealand despite every fibre of its being wanting to pull him our way. The natural flow of big lows from this part of Australia usually sees them moving south east towards New Zealand. But high levels winds (called wind shear) are cutting off the growth of Hamish (which is why he's weakening). Also the massive high in the Tasman Sea is holding him back.

The most likely scenario? I think Hamish will have a long, drawn out, death in the Coral Sea...however his energy, his huge moisture laden energy, will remain in the area. If the high moves out of the Tasman Sea for more than a few days we may well start to see a low spiralling into action and then moving down into the Tasman - perhaps in another week or so. That's just a theory of course. Some predictions could be that the low may travel around the northern fringe of this high taking it well north and then east of us. Other predictions are that the low will simply fall apart by early next week - end of story.

It's certainly nothing for us to be concerned about at the moment, but we've got a special link with all the latest info on him - including his current cyclone category, wind speeds, air pressure, direction of movement and any other news you might find interesting - that link is here.

Philip Duncan

Photo: Hurricane Hamish. Photo / Weather Watch Centre