N2L - I am no expert, but I think the short answer is yes a follie can go from apparently nothing to dominant pretty quickly. My Ob said that a OPK+ is pretty much a sure sign. He said there had been papers published about the possibility of not o'ing after LH surge, but he said that there was little evidence of incidences where this had occured. So a OPK+ should mean ovulation in almost all cases.

AFM - Still no sign of AF... Not happy Jan!