Comet Elenin will be closest to the Sun on Sept 6, 2011. According to prophecies of John Leary, Mary Jane Evan and Veronica Lueken, there will be a comet responsible for hitting the Sun (or a piece of it). We still don't know how big Elenin is. Is it possible to be one of the accompanying comets of the already admitted planet X Tyche?
If there will be the Great Warning before the Chastisement in 2012, it should happen before March-May 2012 when the Great Miracle should occur. (unless God removes both of them from schedule, as some already suggested).
The flee of the Pope from the Vatican is the biggest precursor of the Great Warning. It is said by Mary Jane Evan and JNSR, others. Even the Pleiadian "Henoch prophecy" given to Billy Meier says that pope after John Paul II will be forced to leave Rome and then there will be 888 days hell on Earth. It is interesting to notice such an extraterrestrial prophecy (Henoch=Enoch) bears so much similarity with messages coming from Heaven. Dama Blanca's Third Fatima Secret says there will be 486 days after the current pope is expelled from Rome, when an unclean spirit will reign there. Our Lady in Anguera gives many more details. As of a relative dating She says there will be a moon eclipse visible on that day. Such will take place on June 15, visible from Rome and the Holy Land, Africa, India, China and Australia - i.e. most of the world despite it won't be visible from most of Europe, USA and Latin America.
The calculations might be wrong again. But keep in mind it is not possible unlimited delay. Especially if the Chastisement is in 2012.
If the Great Warning indeed comes this Fall and the events in Rome precede it this Summer, there should be also Middle East war that will reach USA and will be stopped of becoming WW3 by the GW. Still there might be millions even a billion of dead before/around GW. Our Lady in Anguera has never spoken of numbers of dead, before one of the latest messages where She speaks of millions of dead.