Which makes sense because if La Nina remains east-based, it is likley due to some competing force that prevented the event from fully maturing, which would be reflected by the RONI.
What I love about that site is the ability use other climo periods, but that feature isn't working right now, so we're relegated to using 1991-2020, which of coruse skews anomalies colder. When I made the charts, I used the appropriate climo perios...for instance, 1941-1970 for 1974-1975.