Hi,

Let me anwser your question from what I have gathered over the years. I believe CERC's occur generally at night because that's where there is a vorticity max in the atmosphere and thus where the eye would start to generate from, and there is a process known as the nightime convection which leads to insolation ventilating back up into the upper atmosphere. This excessive energy cannot be placed in the center of the eye and is therefore placed somewhere else and a new eye forms and temporaily weakens the prexisting eye. Just my thoughts... I would let Clark take a stab at this one!