You're right, Christian, the strength of the westerly wind anomalies was stronger in 1997 than it was in 2015. The led to stronger eastward-moving Kelvin waves and westward-moving Rossby waves in 1997 than in 2015, resulting in stronger negatively anomalous subsurface heat content in 1998 than in 2016. Accordingly, the current negative OHC anomaly is moderately strong, not extremely strong. As for the PDO, it also is a relevant factor of difference between 1998 and 2016. In 1998 the PDO is thought to have changed phase, from generally positive to generally negative, at the same time tthat the ENSO situation changed from warm to cold in the middle of 1998. This was after being mainly in positive phase during all of the time from the late 1970s until 1998. By contrast, the PDO has been generally in warm phase since 2014, and particularly during 2015 and the first half of 2016. So yes, this PDO backdrop is tending to make it a little harder for a La Nina to set in, and especially for it to be a very strong one when and if it does.