Soaring to Mt Aspiring with Alex

Soaring to Mt Aspiring with Alex

Sunday, March 17, 2013

No Going Back to Fluffy Elephants.

SoaringNZ Issue 32 Editorial
I seem to remember that this time last year, everyone was complaining about the lack of anything resembling a summer. This summer feels completely different. As I write we are coming to the end of a long stable period of anticyclonic, hot, dry weather. There’s a front due through in a day or so and then more of the same is expected. I love it, but then I’m not a farmer waiting for that last rain to fill the crop before harvest and we haven’t had water restrictions in Christchurch this year, so it’s been easy to keep the garden in good nick. There’s been plenty of hay made out in the countryside and there seems to be a bumper crop of summer fruit in the shops. The cherries I’ve been buying are huge. There are a lot of happy glider pilots, although the stable weather is starting to make thermals hard to find.

Memory is short though. In putting this magazine together and sorting through photos from the Nationals and the Youth Soaring Development camp I see there are photos from both events that show snow on the Benmores across from the Omarama airfield. I had forgotten how cold it got during those weeks. We’ve actually had a real mix of weather over the last couple of months. There was so much rain that it wasn’t possible to swim in the Ahiriri river, at Omarama, as it was in flood. Don’t forget that there have been huge floods in Queensland and the north of NZ got clobbered with some of the left overs of those systems.

Weather forecasters have a thankless job. The hit rate these days is pretty good. According to some quick google research, the consensus is that weather reports have around an 87% success rate for the short term (three to five day) forecast. It is long range forecasting that gets really complicated and therefore more inaccurate. Many of us (and by that I mean glider pilots) often mutter how we can do better than the RASP, metvuw or ‘official’ forecast. The thing is that, yes, often we can. I love that one of the side effects, if you will, to learning to fly gliders, is learning to read the weather. We become so attuned to what the atmosphere around us is doing, that we know intuitively what the weather is going to do, often for days ahead.

Are you even aware that you can do this? I bet, right now, you can tell me what direction the wind is from and a rough estimate of its strength. A glance out the window would be enough for you to say if the upper wind is different from what’s happening on the ground and what that means in your location. You can see the amount of cloud cover and say what you expect the wind and the sky will be like by the end of the day? How hot/cold is it going to get? Is the weather you’re experiencing going to stay similar for a few days or will it be completely different tomorrow? Most glider pilots I know can tell me this at least. There you are, you’re forecasting. The weather report just confirms what you already know.

Weather forecasting is an exact science dealing with vast amounts of inexact data. There are so many variables involved in a forecast, from air pressure systems, to humidity, sea temperature, land temperature, land form and so much more that it is amazing that the forecasters can predict anything. My son toyed with the idea of studying meteorology for a while but decided that these days forecasting involves far too much computer work. He’s an out and about sort of person, so this wasn’t the career for him. I was disappointed. I’d really hoped to learn more myself, through him.

In the meantime though, I’ve learnt to read the tephigrams that our forecasters use at competitions. Many thanks there to both David Hirst whose articles on how to do this appeared in issues 3 and 4 and my lecturers in Environmental Physics at University. If there is enough interest we may reprint David’s articles. You can teach yourself more. There is an excellent text book on meteorology that you can buy through university book shops or online book stores – Oxford University Press: The Weather and Climate of Australian and New Zealand by Andrew Sturman and Nigel Tapper. I’ve read it cover to cover. And of course there’s google.

In the meantime, I’m just sorry that gliding has destroyed the innocent pastime of seeing animals in the clouds because once you’ve started seeing lift sources instead, you can never go back to fluffy elephants. Enjoy watching the sky the new way.

Stay safe
Jill McCaw