The GenCon is near to now, with a start from august the eight. I can say we should have the annoucement for the last pack of the cycle at the end of july. So August would be the good month for put the annouce of the fourth cycle at GenCon.

Moreover, between the cycle of carcosa and of Yig, the date of annoucement have been alternated, annoucement for the product of carcosa cycle were more at the middle of the month, those for the forgotten age cycle more at the end of the month. So here we should have a the annoucement of the next cycle more near of the beggining of the month, so GenCon would stick to this model of release.

But we could have other things in the way for gencon. The Return to the Dunwich legacy, or more interesting, a new type of expension , like the Saga of the LotrLCG, for a great campaign based on the masks of nyarlathotep ...

I think so. Cycles are generally announced about 5-6 weeks after the 6th Mythos packs are announced for the previous cycle. Mythos Pack #6 of TFA will be announced right around GenCon (first week of August). So I don't think the 3rd Cycle will be announced at GenCon, that will be too early. Cycle 3 will be announced around mid-September.

I do think we could get a Return to The Dunwich Legacy announcement at GenCon, and/or the next wave of Novellas announced (with the first being on sale at GenCon).

You mean the 4th cycle, because the 3rd is TFA (1st is Dunwich, 2nd is Carcosa).