Harry Medlicott wrote:
My own experience is that these predictions are not all that accurate
and lack the fine detail necessary for an evaluation of gliding
conditions. Personally I look at the latest temp traces available, the
weather pattern, aviation and general forecasts then make a judgement
myself. If you are really keen the best by far is an actual temp
flight in the morning. At the NSW State Comps at Lake Keepit we used a
Jabiru which kept costs to an acceptable minimum. If conditions are
marginal or you want to get the most out of a day, then you can't beat
an on site temp trace,
Harry is tight - using the NOAA temp trace (and stability prediction) is
only a single input into any weather forecast. In terms of accuracy of
its predictions, I have found it to be pretty good for the Darling
Downs, only becoming truly inaccurate when a trough line (or something
else) does something unexpected like speeding up or slowing down. But it
must be a part only of the data used to predict the coming day.
When I am running an XC course or duty instructor and am responsible for
the met forecast, I obtain:-
1. The NOAA temp trace and stability prediction.
2. Latest msl chart from BoM -
http://www.bom.gov.au/weather/national/charts/synoptic.shtml
3. Forecast msl for 10am EST (00 UTC) -
http://www.bom.gov.au/nmoc/products/MSLP_00_Prog.shtml
4. The latest 4 hour loop of IR satellite photos -
http://www.bom.gov.au/products/IDE00902.loop.shtml
5. Appropriate BoM forecast(s) for the intended gliding area - SE Qld
is http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDQ10080.txt
6. The appropriate area forecast(s) from
http://www.airservicesaustralia.com/brief/areabrf.asp
7. Radar/map/actual data integration at the Weather Chaser (this URL
centres on Oakey, Qld)
http://www.theweatherchaser.com/maps/index.html?lat=-27.4&lon=151.74&zoom=10&lid=362
(I have been discussing the integration of NOAA sounding data into
this map with the author - it's a possibility). There is a
'test' page that integrates a great deal more data using layers,
but it is a bit slow, even on a fast DSL!
8. A really good look out of the window (I usually take a walk round
outside with my first cup of coffee). I realise that this
immediately disqualifies me as a met man, but I find it useful!
The last ingredient that needs to be added is experience (preferably
local), this is particularly the case when considering the normal summer
trough line and its interaction with the fronts passing across southern
Australia as its behaviour seems to be hard to predict for the
professionals, let alone an amateur like me!
With all this, I generally find that I am able to be reasonably accurate
in the information I am able to give to students in terms of the day
ahead, including estimated cloud base, day length, some feel for thermal
strengths and of course any particular things to watch out for (ranging
from hazards such as Cb through to low/high triggering when a surface
inversion breaks).
If other people have interesting and useful weather sites that I have
missed, please let me know as I am very keen to add to my knowledge and
the tools in my forecasting chest.
--
Robert Hart [EMAIL PROTECTED]
+61 (0)438 385 533 http://www.hart.wattle.id.au
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