That is a huge map to try to explain. And I am no teacher. But look at the lines. The closer together they are the faster the flow. Remember HP flows clockwise and LP flows counter clockwise. So for example the LP in the SW is pulling warm air from Mexico up into the CONUS. Then connect the LP's and HP's. LP in the SW to HP on the gulf coast. See where that warm is going? Again. I am no teacher and I am drunk. But that is the best I can do. Many people here will be able to explain it better.