Animated model of the path of the jet stream in the northern hemisphere. The jet stream is a fast_moving belt of eastward_moving winds that form at the tropopause at the boundary between cold polar air and warmer temperate air. Wind speed is colour_coded in this model, with red being the fastest, through orange, yellow and cyan to dark blue slowest. The jet stream typically exhibits large_scale meanders, called Rossby waves. The position of the jet stream plays a major role in determining the weather beneath it. The fast_moving air encourages the formation of low pressure beneath it, and regions below the jet stream typically see frequent storms and other low pressure weather phenomena. This animation uses weather and climate observations from NASA磗 MERRA dataset to model 30 days of the jet stream磗 whirling journey over North America.