MEMPHIS, TN (WMC) - Have you ever wondered why one day the wind is calm and the next day, the winds are so strong?
It all has to do with pressure. Even when you don’t always feel the wind, it is never completely still. Air molecules are constantly bouncing around and bumping up against things all around us. All of the colliding creates a force, that force over a given area creates pressure. The air has mass and gravity drags that mass down to the ground. It doesn’t fall straight down but goes out in all directions.
When the sun heats the earth, the heat is not evenly distributed. It heats the earth’s surface unevenly. Heat gets transferred from the air which can create areas of low pressure and high pressure. These pressure differences between the two, causes wind to blow.
Air will flow from high pressure to low pressure. The atmosphere is not attached to the earth and the earth is always turning on its axis which causes wind to rotate, this is known as the Coriolis effect. Wind will blow counterclockwise around an area of low pressure and clockwise around high pressure for the northern hemisphere.
When pressure changes fast over a short distance this causes, gusty, fast moving wind. This most often occurs near cold fronts, areas of low pressure and the jet stream. Wind can blow even faster when it is forced into a narrow area, for example between buildings and mountain passes.