The lines that look similar to contour lines are called isobars. the numbers on the isobars, is the air pressure number. The high and low pressure systems are shown by the H's and L's around the map. Areas of rainfall are shown by diagonal lines.

Warm fronts are shown by lines with small semicircles, and cold fronts are shown by lines with triangles. Wind direction is shown by a small line, with a smaller line  coming out on the left of it. The more smaller lines on it means the more intense wind. The direction the line is pointing (e.g NW), The wind would be travelling that way.