La Nina Weather Update

From NOAA: click here

La Niña Advisory:

  • La Niña conditions are present and slightly favored to persist (~55% chance) through winter 2016-17 (see Image 1, the blue bars represent probability of La Niña)
  • Below Average Sea Surface Temperatures were observed during October into early November, and temperatures are expected to remain in the Weak La Niña range through early winter (see Image 2, bold black line represents the average of all the long range models)
    • Note: The bold black line goes into Neutral territory after the first of the year

Storm track with a La Niña brings cooler/wetter conditions to the Northern United States and dry and warm/dry conditions to the Southern United States (see Image 3)




We took a look back at past weak La Niña and Neutral years. Over the past 65 years, there have been 10 weakl La Niña’s and 24 Neutral episodes. Both of which had a wide range of outcomes.  (See Images 4 and 5 respectively)


Image 5

Image 5

Remember, it is the winter months where we see the most impact from ENSO conditions, because that is when we get most of our rain.  Winter season is flood season in California. The seasonal outlooks will have a La Niña look to them, but remember seasonal outlooks have very low skill.  Recall, last year’s El Niño influenced outlooks, that never developed (i.e. a very wet Southern California was expected but did not happen).

For all winter seasons, the amount of water we receive is always storm by storm dependent. We can only forecast those 7 to 10 days out.  October was a nice start to our winter season, but we still have a long way to go!

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