Evaluation of turbulence forecasts with the aLMo

High altitude clear-air turbulence (CAT) remains a significant forecast problem for aviation. The number of fatal accidents involving CAT encounters by jet aircraft is relatively low though, but serious injuries have occurred, especially when severe CAT is encountered suddenly and unexpectedly and passengers have unfasten seat belts. CAT phenomena are therefore of high practical importance for air traffic; air transport companies have a vital interest in receiving early warnings of likely CAT areas. It is a matter of passenger comfort and safety as well as aircraft safety. In cases of severe or extreme CAT, structural damage to aircraft may result. Aircraft material fatigue arising from severe CAT can reduce lifespan of airplanes and hence be of high economic importance. There is also a significant increase in fuel consumption during turbulent flights (Ellrod and Knapp, 1991).