Updated 11/18/17 La Nina Conditions through the Winter 2017-18

Synopsis: La Niña conditions are predicted to continue (~65-75% chance) at least through the Northern Hemisphere winter 2017-18. During October, weak La Niña conditions emerged as reflected by below-average sea surface temperatures (SSTs) across most of the central and eastern equatorial Pacific Ocean (Fig. 1). The weekly Niño indices were variable during the month, with values near -0.5 C during the past week in the Niño- 3.4 and Niño-3 regions (Fig. 2). Sub-surface temperatures remained below average during October (Fig. 3), reflecting the anomalously shallow depth of the thermocline across the central and eastern Pacific (Fig. 4). Also, convection was suppressed near the International Date Line and slightly enhanced over parts of the Maritime Continent and the Philippines (Fig. 5). Over the equatorial Pacific Ocean, low-level trade winds were mainly near average, but the upper-level winds were strongly anomalously westerly and the Southern Oscillation Index was positive. Overall, the ocean and atmosphere system reflects the onset of La Niña conditions. For the remainder of the Northern Hemisphere fall and winter 2017-18, a weak La Niña is favored in the model averages of the IRI/CPC plume (Fig. 6) and also in the North American MultiModel Ensemble (NMME) (Fig. 7). The consensus of forecasters is for the event to continue through approximately February-April 2018. In summary, La Niña conditions are predicted to continue (~65-75% chance) at least through the Northern Hemisphere winter (click CPC/IRI consensus forecast for the chance of each outcome for each 3-month period). La Niña is likely to affect temperature and precipitation across the United States during the upcoming months (the 3-month seasonal temperature and precipitation outlooks will be updated on Thursday November 16th). The outlooks generally favor above-average temperatures and below-median precipitation across the southern tier of the United States, and below-average temperatures and abovemedian precipitation across the northern tier of the United States. This discussion is a consolidated effort of the National Oceanic and Atmospheric Administration (NOAA), NOAA’s National Weather Service, and their funded institutions. Oceanic and atmospheric conditions are updated weekly on the Climate Prediction Center web site (El Niño/La Niña Current Conditions and Expert Discussions). Forecasts are also updated monthly in the Forecast Forum of CPC’s Climate Diagnostics Bulletin. Additional perspectives and analysis are also available in an ENSO blog. The next ENSO Diagnostics Discussion is scheduled for 14 December 2017. To receive an e-mail notification when the monthly ENSO Diagnostic Discussions are released, please send an e-mail message to: ncep.list.enso-update@noaa.gov.



  1. Hope you enjoyed the rain……1-2 inches in S. California and more in Ventura.


  2. Pretty soon it will be there and quite a bit I think… 4-8 inches of rain or more in the lowlands with much higher amounts in the orographically favored locations. Perhaps over 20 inches in some mountain areas. Should be a very dangerous storm to some canyon locations as well as coastal areas where the high tides, wind, and flooding makes a high impact.

  3. Thanks very much….I appreciate your interest….I will try to keep you informed of extended Sierra weather in my summary.

  4. Great site! My daughter’s class is studying weather. Her teacher wrote: ” I was wondering if there are any meteorologists out there or just huge weather buffs who would like to come do a presentation to the sixth graders about air and water currents, in particular El Nino years. We’ve been studying it in class but I am not a specialist in this area and would love to have someone with more knowledge explain the factors that influence weather.” I wondered if this us up your alley at all? Let me know if so, and I’ll find out more particulars. Thanks a lot. –Teal

    • Teal,

      Sure I have done this for my kids and several classes at Children’s Health Council where I worked for over 14 years….I would need an internet connection that could be projected onto a screen from my laptop so that I could use visuals and they could see first hand how weather forecasts are done and the forces that causes weather changes……

      What school and what are the ages of the students?

      Richard Stolee

      • Thank you! The kids will love it. These are 6th graders at JLS in Palo Alto. What’s the best way to contact you to work out date/time etc?


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