Last month, NOAA declared that based on the most recent data, the chance of a La Niña developing was only about 40 percent, and they removed the La Niña watch that they had declared earlier this summer.  One month later, and the La Niña watch has returned with a 70% chance of occurring.  The change is due to evolving conditions in the eastern Pacific Ocean, which are back to looking like a La Niña is coming.  However, forecasters think that it will likely be a weak one and that it may not last long enough to officially be declared a La Niña episode, giving it a 55% chance of lasting through the winter.  You can read more about it at https://www.climate.gov/news-features/blogs/enso/anticipation-october-2016-enso-forecast.

3 La Nina conditions