Foehn wind 3) Mechanical mixing: When river water passes over rocks, turbulence is generated in the form of rapids, and white water reveals the turbulent mixing of the water with the air above. Similarly, as air passes over mountains, turbulence occurs and the atmosphere is mixed in the vertical. This mixing generally leads to a downward warming and upward moistening of the cross-mountain airflow, and consequently to warmer, drier foehn winds in the valleys downwind. 4) Radiative warming: Dry foehn conditions are responsible for the occurrence of rain shadows in the lee of mountains, where clear, sunny conditions prevail. This often leads
Weather is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Human beings have attempted to predict the weather informally for millennia, and formally since at least the nineteenth century. Weather forecasts are made by collecting quantitative data about the current state of the atmosphere and using scientific understanding of atmospheric processes to project how the atmosphere will evolve. Once an all-human endeavor based mainly upon changes in barometric pressure, current weather conditions, and sky condition, forecast models are now used to determine future conditions. On the other hand,