Weather plays an important role in the maintenance of airline schedules and also impacts air-safety. Clear-air turbulence (CAT) is one such weather phenomena. While aviation turbulence events have always been present, there is renewed interest in this phenomenon due to increasing air traffic and possible effects of global warming. There have been a number of studies regarding (CAT) and many indices are in use for forecasting. However, many of the indices predict large regions and there continues to be a need for theories and methods which can predict more well defined regions. In this talk, the physical mechanisms, simulation and forecasting methods will be discussed.