"Bernard Burton" wrote in message
...
The answer is yes, Alistair. Moist air is less dense than dry air at the
same temperature, and thus more bouyant. As Martin says, using the virtual
temperature in your calculations will take this into account.

Got it! To work out the buoyancy (instability) you have to use the virtual
temperature, not the potential temperature.

Thanks Martin and Bernard,

Cheers, Alastair.