Meteorologists of the National Weather Service collect data from satellites, instruments attached to weather balloons, and radar. This info. is used to describe weather conditions in the atmosphere...
As you probably know, the National Weather Service is a United States Government organization so not many people know. Contact a NWS meteorologist for help.
The National Weather Service makes weather maps with special lines. Isotherm is a line that connects points of equal temperature. Isobar is a line that is drawn to connect equal atmosphere pressure.