text: A tropical disturbance is not often associated with a surface low.  So it is not a tropical cyclone.\n(In the Atlantic Basin) As TROPICAL WAVES exit the coast of Africa, the associated thunderstorms are fueled by warm ocean waters.  This means a large area of convection develops.  Again, there is no surface low, so it is not a tropical cyclone.\nStorms continue to grow, usually in a pulse type pattern.  Daytime heating will allow numerous storms to fire, then the convection settles down a bit at night.\nOnce the system has full tropical characteristics, and a surface low pressure.... it is considered a tropical cyclone (depression/storm, depending on estimated, or measured wind speeds.)\n\n\nHope this answers your question.