Isobars

Isobars are lines on a weather map that connect areas of equal barometric pressure. They are read very much the same way you would read the altitude lines on a TOPO map. Lines that are spaced far apart or “loose” indicate a shallow pressure gradient from one area to another with light or no wind. Wind generally tends to move along isobar lines from high pressure zones to low pressure zones. Lines that are very close together or “compressed” indicate a steep pressure gradient and may indicate higher winds as the pressure tries to equalize. If there are more than 2 isobars in your state (about the size of Wa.) they are compressed.