I didn't save the fire weather forecast, but remember it was for about 16km/h S in the monring, increasing to 25km/h SSW in the afternoon.
Temp Trace
The temp trace shows nice unstable air, the lower inversion should
be reachable from 18 degrees, so we could probably have started earlier,
it looks like the second inversion should break by 27 degrees, and let
us through to 7500ft, but didn't seem quite that good in practice.
Wind speed is shown as south east down low, going south west above 4000
feet, with strength around 15 kts right up to 7000 ft. I didnt notice
as much direction swing as expected.
Thanks to the Gliding Association and BoM for these forecasts see http://slash.dotat.org/cgi-bin/atmos?loc=94610&latest=1
for the latest forecast.
Synoptic Charts
Below is the surface chart from the day, you can see the good wind
direction from the high pressure ridge. There is also a huge tropical
low to the north (almost a cyclone) which may have helped out with the
instability, the lift seemed better than a typical summer high pressure
day.
Thanks to BoM www.bom.gov.au for this stuff
Below is the 4 day forecast chart starting from the day of the flight, useful because this is the forecast we usually try to guess when its going to be a good day from, note 9pm is EST and means 6pm in WA note lots of rain inland, from the tropical low.
Wind Speeds,
below are records of wind speed from Gin Gin and Cunderdin. You
can see the seabreeze hit GinGin (west of my track) about 13:00, the sea
breeze didn't make it to Cunderdin (east of my track) at all, so its possible
some of the good lift later in the day was helped by some sea breeze convergence.
Thanks to BoM www.bom.gov.au again for this data - available at http://www.bom.gov.au/products/IDW60199.shtml
| Current Observations for Gingin Airport | |||||||||
| Date Time | Temp | Dew point | Rel Hum | Wind dir | Wind speed | Wind gust | Press | ||
| (AWST) | (deg C) | (deg C) | (%) | (km/h) | (knots) | (km/h) | (knots) | (hPa) | |
| 25 23:00 | 17.9 | 12.4 | 70 | S | 18 | 10 | 28 | 15 | 1017.9 |
| 25 22:00 | 18.1 | 12.6 | 70 | S | 15 | 8 | 22 | 12 | 1017.6 |
| 25 21:00 | 18.8 | 12.6 | 67 | S | 17 | 9 | 22 | 12 | 1017.2 |
| 25 20:00 | 19.6 | 12.6 | 64 | S | 18 | 10 | 26 | 14 | 1016.9 |
| 25 19:00 | 20.8 | 12 | 57 | SSW | 26 | 14 | 37 | 20 | 1016.5 |
| 25 18:00 | 22.5 | 10.7 | 47 | SSW | 31 | 17 | 43 | 23 | 1015.7 |
| 25 17:00 | 23.2 | 11.3 | 47 | SSW | 33 | 18 | 43 | 23 | 1015.2 |
| 25 16:00 | 25.2 | 10.7 | 40 | SW | 35 | 19 | 46 | 25 | 1014.6 |
| 25 15:00 | 26.4 | 9.7 | 35 | SSW | 31 | 17 | 41 | 22 | 1014.6 |
| 25 14:00 | 26 | 9.4 | 35 | SSW | 31 | 17 | 43 | 23 | 1015 |
| 25 13:00 | 26.6 | 7.6 | 30 | SSW | 18 | 10 | 30 | 16 | 1015.1 |
| 25 12:00 | 25.4 | 7.1 | 31 | SE | 18 | 10 | 28 | 15 | 1015.7 |
| 25 11:00 | 23.9 | 8.4 | 37 | SSE | 13 | 7 | 22 | 12 | 1016.4 |
| 25 10:00 | 22.2 | 9.1 | 43 | ESE | 18 | 10 | 28 | 15 | 1017 |
| 25 09:00 | 19.8 | 9.7 | 52 | SE | 17 | 9 | 24 | 13 | 1017.1 |
| 25 08:00 | 18 | 9.6 | 58 | SE | 18 | 10 | 26 | 14 | 1017.3 |
| 25 07:00 | 14.7 | 9.5 | 71 | SE | 13 | 7 | 18 | 10 | 1016.8 |
| 25 06:00 | 9.7 | 7.7 | 87 | S | 9 | 5 | 11 | 6 | 1016.3 |
| 25 05:00 | 9.5 | 7.5 | 87 | SE | 9 | 5 | 11 | 6 | 1015.5 |
| 25 04:00 | 10.1 | 7.7 | 85 | SSE | 6 | 3 | 9 | 5 | 1014.8 |
| 25 03:00 | 11.2 | 8.6 | 84 | S | 9 | 5 | 11 | 6 | 1014.4 |
| 25 02:00 | 12.1 | 8.8 | 80 | SSE | 9 | 5 | 11 | 6 | 1014.5 |
| 25 01:00 | 12.2 | 7.5 | 73 | SE | 7 | 4 | 9 | 5 | 1014.7 |
| 25 00:00 | 13 | 8.5 | 74 | CALM | 6 | 3 | 1014.9 | ||
| Current Observations for Cunderdin Airfield | |||||||||
| Date Time | Temp | Dew point | Rel Hum | Wind dir | Wind speed | Wind gust | Press | ||
| (AWST) | (deg C) | (deg C) | (%) | (km/h) | (knots) | (km/h) | (knots) | (hPa) | |
| 25 23:00 | 23 | 2 | 25 | SSE | 22 | 12 | 30 | 16 | 1017 |
| 25 22:00 | 23.5 | 2.4 | 25 | SSE | 20 | 11 | 28 | 15 | 1016.7 |
| 25 21:00 | 24.5 | 2.1 | 23 | SSE | 17 | 9 | 20 | 11 | 1016.5 |
| 25 20:00 | 25.7 | 2.4 | 22 | SSE | 18 | 10 | 24 | 13 | 1016 |
| 25 19:00 | 27.6 | 2.7 | 20 | SSE | 24 | 13 | 33 | 18 | 1015.4 |
| 25 18:00 | 28.8 | 3.6 | 20 | SSE | 22 | 12 | 31 | 17 | 1014.3 |
| 25 17:00 | 30.3 | 4.2 | 19 | SSE | 20 | 11 | 28 | 15 | 1013.8 |
| 25 16:00 | 29.5 | 3.5 | 19 | SE | 17 | 9 | 30 | 16 | 1013.8 |
| 25 15:00 | 29.5 | 5.6 | 22 | SSE | 20 | 11 | 30 | 16 | 1014.1 |
| 25 14:00 | 28.2 | 5.1 | 23 | SSE | 17 | 9 | 30 | 16 | 1014.8 |
| 25 13:00 | 27.2 | 4.3 | 23 | S | 17 | 9 | 24 | 13 | 1015.1 |
| 25 12:00 | 26.8 | 7.3 | 29 | SSE | 18 | 10 | 31 | 17 | 1015.4 |
| 25 11:00 | 24.4 | 7.6 | 34 | SE | 18 | 10 | 26 | 14 | 1016.3 |
| 25 10:00 | 22.6 | 8.7 | 41 | SE | 20 | 11 | 30 | 16 | 1017 |
| 25 09:00 | 20.2 | 9.2 | 49 | SE | 20 | 11 | 30 | 16 | 1017 |
| 25 08:00 | 18.4 | 9.5 | 56 | ESE | 20 | 11 | 30 | 16 | 1017.1 |
| 25 07:00 | 16.6 | 9.3 | 62 | ESE | 18 | 10 | 26 | 14 | 1016.5 |
| 25 06:00 | 14.1 | 8.5 | 69 | SE | 11 | 6 | 13 | 7 | 1015.8 |
| 25 05:00 | 13.3 | 7.1 | 66 | S | 13 | 7 | 15 | 8 | 1015.3 |
| 25 04:00 | 13.8 | 6.9 | 63 | S | 13 | 7 | 17 | 9 | 1014.4 |
| 25 03:00 | 14.7 | 7.3 | 61 | S | 13 | 7 | 18 | 10 | 1014.2 |
| 25 02:00 | 15.1 | 7.7 | 61 | S | 17 | 9 | 24 | 13 | 1014.5 |
| 25 01:00 | 15.4 | 7.5 | 59 | SW | 11 | 6 | 15 | 8 | 1014.8 |
| 25 00:00 | 16.3 | 7 | 54 | SW | 17 | 9 | 22 | 12 | 1014.3 |
Mike Dufty 27/01/03