While we currently expect this El Nino to transition to neutral by next summer, what comes next is still an open question.  It's really just too far into the future to make a prediction that would be anything except a guess.  The 1997/98 did quickly transition to a La Nina, but the Pacific ocean after the 1982/83 event only became marginally below average and the La Nino didn't develop until the following winter (1984/85).