Will this La Nina last? Looking only at the surface maps may be misleading. Despite the cool equatorial ocean temps, looking at the subsurface indicates otherwise. A significant +2C mass of warm water will come to the surface as it migrates eastward, and could have quite an effect on the surface conditions when it does. The Southern Oscillation index is positive, but only for 3 months now, and not strongly positive at that. And we have seen rapid shifts from one phase to another in the past. So, for those calling for the extended 'very strong' La Nina event to continue through the northern hemisphere winter, keep in mind some of these factors.