Wind speed based on

Would it be possible to have wind speed based on such things as density and temperature ? As it is if i have an explosion then ramp up the wind speed the whole blob of smoke moves of as one at the same speed. I would like the look whereby the smoke at the top of the plume blows away faster as it would do in a constant emission scenario

Yes. You could try to use an AddScaledVector node to do that. Pass the velocity field and the density field through it and adjust the Vector parameter.
In explosion.rea buoyancy is implemented like this. The AddScaledVector.Vector parameter then simply points upwards.

OK will look into that. Working with TFDv1 Curiously a plane with normal force does a good effect with wind being stronger at the top. I would have thought I would have had to set up a gradient on the plane but no a single poly plane does exactly what want. After all these years never got round to playing with this idea !! Is it due to the temperature decay with buoyancy having less effect if so why does wind not do it ? ?

No …that was an illusion !! I will try several planes with varying levels of force. Even a gradient in the colour channel is not doing what i want.

Yeah the staggered planes work OK