Alfa Colorado

I am the proud new owner of an '87 Spider Veloce. The car runs great but there is a warning beep that has been coming on but with no warning light or indicator. It stops if the car is on an incline with the nose up. Very annoying. On the up side, I can barely hear it at 65mph with the top down.
Any help or insight to possible solutions to this random warning beep would be great.