Possible Clues:

• On a run, I cry - I show the pressure
• Map line of barometric pressure
• Equal-pressure line
• Line on map connecting places of equal atmospheric pressure
• Boris, a mad feature on the map
• I thus forbid the same pressure along it
• Meteorological indicator
• A biro's taken out to produce curve on map
• I thus forbid the same pressure along this line
• Line on a weather report map