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
