This is a picture of an example of what the pressure gradient lines or Isobars, Lines in equal Air pressure. The tighter the Isobars or lines the stronger the winds. Everyone knows that winds flow from upper ridge highs to Upper low systems or winds aloft since winds move up word. So Everyone may ask me what is a Ridge. Well a ridge is a big huge volume of sinking high pressure air. If you expect Hot temperatures a surface ridge is building. I'm Meteorologist David Schlotthauer