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August 2019 El Niño Update: Stick a fork in it

The El Niño of 2019 is officially done. Near-average conditions in the tropical Pacific indicate that we have returned to ENSO-neutral conditions (neither El Niño or La Niña is present). Forecasters continue to favor ENSO-neutral (50-55% chance) through the Northern Hemisphere winter. 

What’s on our plate?

The July Niño3.4 index, our primary index for monitoring ENSO, was 0.4°C above the long-term average, falling below the El Niño threshold of 0.5°C for the first time since last September. In addition, tropical atmospheric conditions have trended toward neutral, as the cloudiness and rainfall over the Pacific were near average over the past month. The trade winds also have been near average lately, indicating that Walker circulation, which weakens during El Niño, has shown signs of rebounding.  

SST graph

Monthly sea surface temperature in the Niño 3.4 region of the tropical Pacific for 2018–19 (purple line) and all other El Niño years since 1950. Climate.gov graph based on ERSSTv5 temperature data.

                                                         

Based on these latest indicators from the tropical ocean and atmosphere, NOAA forecasters have declared that El Niño has ended and neutral conditions have returned. Does a return to neutral mean that average weather conditions are expected to prevail around the globe? As Michelle pointed out a couple years ago, the answer is an emphatic NO.  A return to neutral means that we will not get that predictable influence from El Niño or La Niña, but the atmosphere is certainly capable of wild swings without a push from either influence.  Basically, ENSO-neutral means that the job of seasonal forecasters gets a bit tougher because we do not have that ENSO influence that we potentially can predict several months in advance (in a probabilistic form).           

A change to neutral could also impact the Atlantic hurricane season, which typically ramps up this time of year and peaks in early-to-mid September.  El Niño tends to produce hostile conditions for Atlantic hurricanes, as explained more thoroughly in Dr. Phil Klotzbach’s guest post, so a return to neutral means  that we will not get a decisive push from El Niño to the Atlantic.  The updated NOAA Atlantic Hurricane Season Outlook is now available, so be sure to check how these changing ENSO conditions and other drivers are impacting the Atlantic hurricane season.    

SST animation

Sea surface temperature from June 1 through July 27, 2019. The region of cool water in the tropical eastern Pacific, called the eastern Pacific cold tongue, is clearly visible along the Equator, surrounded by warmer waters to the north and south. The wavy features along the northern and southern borders between the cold tongue and the warmer waters are tropical instability waves. The waves on the north side are clearer in part due to the stronger temperature gradient on that side of the cold tongue. Map by NOAA Climate.gov from CDR data.

And just to drive home that ENSO-neutral doesn’t necessarily mean “bland and boring,” a closer look at the weekly ocean surface temperature reveals some fascinating, wavy features over the eastern Pacific. Emily discussed these interesting features, called tropical instability waves, a few years ago. These waves can produce some dramatic week-to-week swings in the Niño3.4 index, but their effects tend to get washed out in the monthly and seasonally averaged index. That doesn’t mean that these waves cannot impact ENSO – check out Emily’s post to find out more!

What’s on the menu?

Will ENSO-neutral conditions continue through fall and winter? Similar to last month, most of the computer models we consult predict that the ocean surface temperature in the Nino3.4 region will remain near average throughout this period. NOAA forecasters favor this outcome, predicting a 50-55% chance of neutral conditions remaining through winter.   

Vertical bar histogram

Vertical bar histogram showing probabilities for La Niña (blue), neutral (gray), and El Niño (red) conditions for the remainder of 2019 and into early 2020. Thin lines show climatological (historical average) probabilities for these same three ENSO conditions. Figure from IRI.

Is it possible for an El Niño to end in the spring or summer only to reemerge again in the following fall? Yes, it can happen! (You can get a sense of this from close inspection of the first figure above.) We have seen this sort of situation a few times since 1950, the latest being the reemergence of El Niño in the fall of 1977. Some forecast models favor this outcome, and forecasters consider this plausible, but not the most likely outcome, predicting a 30% chance of El Niño next fall and winter.

The current forecast underscores that we don’t have a sure bet this far in advance – there are many possible outcomes for the coming fall and winter. The forecast probabilities still give us useful information on what outcome is favored at this time. As conditions evolve, we will gather more information that will allow us to refine these probabilities and hopefully narrow the forecast uncertainty. You can count on us to stay on top of these developments and to give you the latest!     

This ain’t Mama’s home cookin’!

I know what you’re thinking – this blog post isn’t the same sweet, tasty morsel of freshly baked ENSO goodness that Emily usually delivers to us. I feel the same way. Emily is away this week, but don’t worry, she will be back soon for a post later in August. That means you’ll want to check back in a few weeks to satisfy your next ENSO craving!   

 

Comments

I have been reading everything and I think that we could see an early winter but well have to wait and see.things change each and every day.

I have read nothing and think we could see a mild winter or maybe even a cold one; wait winter is always cold nd begins on the same day every year.

In reply to by Debra Edge

I think storms are about to ramp up...The El Niño winds that helped stomp down potential hurricanes so far this year are dying, federal forecasters said Thursday. Quick Question: The season will be more active than what is considered normal? Jacob

Now that El Nino is dead, it's possible La Nina may develop between late 2019 and mid 2021. That may mean more hurricanes and tropical storms in the Atlantic Ocean, Gulf of Mexico and the Caribbean Sea. We have had hurricanes brush although not make landfall in New England. But we did have tropical storms in New England: Bertha 96, Danny 97, Floyd 99, Allison 2001, a 2004 tropical storm, Ophelia 2005, a 2006 tropical storm, Noel 2007, Hanna 2008, Earl 2010, Irene 2011 and Philippe 2017. Sooner or later, New England luck will run out; they and Long Island will be hit by hurricanes in future years. The last one in New England was Hurricane Bob in August 1991.

From the Climate Prediction Center maps, it looks as though the temps in the Midwest will be a tad above normal. Everyone keeps saying they "think" it will be an early fall and cooler than normal but I am getting this from kids doing YouTube videos on what to expect. We might want to stick to what to what the pros say.

How does ENSO affect (or does it) the Pacific hurricane season?

Good question! We wrote an entire blog post on this topic, which you can read here. In short, El Nino's lead to more hurricanes and the eastern/central Pacific and La Nina leads to less.

In reply to by Bailey

I love those 'tropical instability waves'. I think I called them a Von Karman street in my last communique (titled "Au Contraire" which turned-out to be correct by-the-way!) And it is interesting that they are mirrored in the Atlantic as well. Could there be a common cause for both?

NASA is reporting a solar minimum and there has been no sun flare activity. Are we headed towards a mini ice age? If so how could that effect other seasons?

G'day, El Nino will peak 26 December 2019, be curtailed by La Nina 20 January 2020. There is a rash prediction. Just two-and-a-half months off. The earth-moon barycentre will be at top of the mantle, crossing 26 December below the equator in the west Pacific, as marked by the shadow called a total solar eclipse. The molten metal ocean below, vastly more massive than the water one above, cannot lift the much more massive yet mantle, so big flow currents result. When the barycentre is at the top of the mantle its distance from the earth’s daily rotation-centre is at max so, as with all physical bodies with two turning axes, heat is generated and maximum heat is generated then. On 20 January, a lunar eclipse marks the barycentre being at the bottom of the mantle again. The historical back record is perfect, but all met people switch their minds off at the top of the lithosphere. At the bottom of mantle, the temperature is about 5,000 degrees Kelvin. In space it is 3 degrees Kelvin. So that heat flows which way? We all forgot the tidal force of the sun, half that of the moon at this distance. So the barycentre dos not live at the midpoint of the mantle it goes top to bottom of mantle lunar monthly. Hence the mantle, core and crust. And our very large geomagnetic field and its dipole and non-dipole components. The internal heat of the Earth is tidal and magnetic. That, incidentally drives climate change, not trace atmospheric carbon from machine, cow and car farts. Can't tell Greta or her Mum, they are drowning in correspondence. Nor the IPCC, Al Gore, Royal Society of London, "Nature", etc. , The postulated ball of uranium at the centre of the earth’s inner core does not exist. It was just Arthur Holmes' guess when he discovered plate tectonics in 1928. He needed an engine to move his basalt marine plates, so guessed (as he admitted) at it being radioactive uranium. But you can't push basalt plates. They shear and crumple. You instead drag them (and the continental plates) west at variable rates. All else follows. The moon arrived maybe about 2.3 b.y. back, and earth's tidal effect on it can be seen as the dark mare. Lunar crater-based dating is total nonsense, as the craters are mostly gas vents. Even the ejecta array ones are simply radial tension cracks. Some centre way off the obviously-linked crater. So, stars are also magnetic hells, not radioactive ones. The astronomers bought some very wrong geology theory, without much thinking and transferred it to all stars. Ho hum. Don't blame Holmes. He was probably the best geologist ever. A reprint of his 1928 plate tectonics diagram is in every edition of his classic "Principles of Physical Geology" book, 1946, last edition 1966 (I think.) If you don't make huge mistakes in geology (here too, of course?) you aren't working. There would be no drilling rigs - we would just say "mine here" and point. Peter Spencer Ravenscroft Geologist, Australia. p.s.ravenscroft@gmail.com phone international 617 3289 4470 All info always public domain and free.

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