<div class="eI2">Geopotential height Temperature at 500 hPa </div> Geopotential height at 500 hPa (solid line)<br> Temperature at 500 hPa (colored, dashed)<br><br> The maps show the predominant tropospheric waves (trough or ridge). They virtually control the ''weather'' (dry, warm / wet, cold) and the long waves drive the smaller synoptic waves. Thus, this upper-level chart illustrates the dynamics of our atmosphere. </div>