The wind speeds at Mt. Hotham were north at 22 knots gusting to 30 knots at 9:30 AM. These values are four knots less than yesterday, still out of the north. Ollie feels that the winds are still too strong for safe hang gliding. He would want Mt. Hotham winds to be in the 18 knot or less range before we went up the hill (Mystic Hill) to check things out on launch.

What is unclear to me is just how the RASP model can forecast west northwest winds at Mt. Hotham for 9 AM and 10 AM, but the measurements at those times are north, with one  north northwest. The forecasted strengths look right for Mt. Hotham. Maybe I should forgive the model for being a little bit off in direction.

As I vaguely recall, Dr. Jack has dealt seriously with orthographic effects, because his models were developed with the California Sierras in mind. I don't know how the equations that he uses to account for topography relate to what we might see in the Victorian Alps (here).

The forecasts for winds (averaged throughout the boundary layer - the layer in which we will find thermals) for the afternoon (3 PM) are twelve to fourteen knots out of the west northwest to west along the range on the east side of the Kiewa valley. That seems to me to be a bit windy for enjoyable flying in the mountains, but I'm not positive about that.

Based on the Mt. Hotham winds, and the "forecast" for an approaching cold front ("A cold front will move across southern Victoria to reach the Tasman Sea today."), the day is called. We are in northeast Victoria, so I'm unclear about how the cold front is supposed to affect us. Ollie and Phil think that the wind strength should be increasing. I think that it will be decreasing in the mountains (from 26 knots at Mt. Hotham) and increasing in the flats from five knots (Wangaratta) and going to west southwest there. I also predict (using RASP) more westerly direction for the winds in the mountains in the afternoon.

It is also unclear exactly where we are supposed to be launching from given the wind direction and strength. With a west wind with a little south component (like out on the flats, but not forecasted necessarily here), Emu would be the go. Mystic would be the spot for a northerly wind.

We'll see how well the model does this evening after we look back over the day. Too bad we don't have recorded wind speed and direction measurements at Emu, Mystic, Mt. Beauty, and Buffalo.

The day was called at 10:15.

Yesterday the winds lightened up substantially at Mt. Hotham and increased in the flats. The major weather feature was not the winds but the over development. So even if we did get it wrong for the winds the day would not have been good for flying.