2015 El Niño?

[Tor Bejnar]

These update automatically, so having them near the top of the page may be convenient.

[Sigmetnow]

Crops in India in Dire Need of Rain as El Nino Hurts Monsoon

Monsoon rainfall, which waters more than half India’s 145 million hectares (360 million acres) of crop land, was below the 50-year average in July and August, and September will be not be any better, according to the India Meteorological Department. Downpour since the start of monsoon on June 1 are 12 percent below the average, department data show.

El Nino this year is the strongest since 1997-98, according Australia’s Bureau of Meteorology. The below-par performance of the monsoon also imperils the outlook of winter crops including wheat, which are mostly irrigated. The water levels at India’s 91 main reservoirs is 58 percent of the capacity as of Aug. 27, less than the 88 percent average of the last 10 years, official data show.

http://www.bloomberg.com/news/articles/2015-09-04/crops-in-india-in-dire-need-of-rains-as-el-nino-stings-monsoon

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has drifted up to -15.1:

[maltose]

Is there a Nino Index update tomorrow (Monday) or does Labor Day delay that?

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved up to -14.5:

[AbruptSLR]

Is there a Nino Index update tomorrow (Monday) or does Labor Day delay that?

Here is the answer to your question (the Nino 3.4 has dropped down to 2.1 while the Nino 1+2 has moved up to 2.2):

                     Nino1+2      Nino3        Nino34        Nino4
 Week           SST SSTA    SST SSTA  SST SSTA   SST SSTA

 19AUG2015     22.4 1.7     27.2 2.2     28.9 2.1     29.7 1.1
 26AUG2015     22.6 2.0     27.3 2.3     29.0 2.2     29.7 1.1
 02SEP2015     22.7 2.2     27.3 2.4     28.9 2.1     29.7 1.0

[AbruptSLR]

Per NOAA's "ENSO: Recent Evolution, Current Status and Predictions", Issued Sept 7 2015:

The first image shows that the ONI now has 5 consecutive overlapping 3-month averages periods over +0.5C so we are now officially in an El Nino period per NOAA's definition
The second attached image shows the Eq Pac Upper Ocean Heat Anom Evolution.

Extract: "El Niño conditions are present.
Positive equatorial sea surface temperature (SST) anomalies continue across most of the Pacific Ocean.
There is a greater than 90% chance that El Niño will continue through Northern Hemisphere winter 2015-16, and around an 85% chance it will last into early spring 2016."

[AbruptSLR]

Per the attached plot & the following data issued today by the BoM, the 30-day moving average SOI has moved up to -14.7:

20150808,20150906,-14.7

[Pmt111500]

I've been hearing people like to compare this El Nino to the huge one that developped 1997. Here presented side by side is the sea surface temperatures of last weeks of august and I'd say 2015 still has some way to go to be called a huge one. More notable is the relative heat in the Southern Indian Ocean and North Pacific, and the cold blob of the North Atlantic. Yes the temperatures over at Nino region are pretty same though 1997 was more widespread at this stage. Compared to the temperatures elsewhere in the world ocean this is not a huge one.

[AbruptSLR]

The four attached images were all issued today by the BoM through the week ending Sept 6 2015, for the Nino 1, 2, 3 and 4 indices, respectively.  This plots support the concept that the current EKW pulse is beginning to crest against South America (note that both the Nino 1 and 2 indices are now increasing), so we will soon enter a trough that may (or may not) facilitate another EKW pulse.

[AbruptSLR]

The first two images were issued today by the BoM for the week ending Sept 6 2015, with the first plot showing that the BoM Nino 3.4 has dropped down to +1.87, while the second plot shows the IOD is +0.7.  This supports the concept that the current EKW pulse is cresting, and that the coming trough may well be followed by another EKW pulse (due to the increasingly positive IOD).

The third & fourth images show the Albany 5S-5S wind anom. forecasts for Sept 7 thru 14 2015, for the 850-hPa and the 200-hPa zonal winds, respectively.  These plots show that the atmosphere continues to support strengthening El Nino conditions.

[AbruptSLR]

I've been hearing people like to compare this El Nino to the huge one that developped 1997. Here presented side by side is the sea surface temperatures of last weeks of august and I'd say 2015 still has some way to go to be called a huge one. More notable is the relative heat in the Southern Indian Ocean and North Pacific, and the cold blob of the North Atlantic. Yes the temperatures over at Nino region are pretty same though 1997 was more widespread at this stage. Compared to the temperatures elsewhere in the world ocean this is not a huge one.

While some people feel comforted that the 2015 El Nino is lagging in development behind the 97-98 event, the attached image that bigB posted in Reply #1025, shows that our the development of our current event is far ahead of the 82-83, I am concerned that we are likely still on track to a monster El Nino in 15-16.  The 82-83 is probably a better go-by as it occurred at the beginning of its positive PDO cycle (as is the current case) while the 97-98 event occurred at the very end of its positive PDO cycle.  Furthermore, as my last post indicates, currently both the IOD is becoming increasingly positive and Bjerknes feedback is positive.

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved down to -15.4:

[AbruptSLR]

The first NOAA image shows the modeled EKW on Sept 5 2015, showing that it is still in the process of surfacing.

The second NOAA image circa Sept 9 2015, shows that the Eq Pac. Upper Ocean Heat Content Anom. is slowly declining which may (or may not) indicate that we are now entering a trough in heat content before the next EKW pulse.

The third image shows the Albany 5S-5N 850-hPa Wind Anom. forecast from Sept 9 to 16 2015, showing some westerly wind activity that may (or may not) help feed the next EKW pulse.

[gideonlow]

There has been a lot of discussion recently about the staying power of "The Blob" in the face of this year's El Niño event, with various opinions from "inconsequential" to "it will take months and many storms for The Blob to be affected" to "it's not going away" . . . One thing I have not yet seen discussed is the amount (or depth) of heat underlying the SST anomalies outside of the equatorial regions.

For the Niño regions, the SL anomalies and upper ocean heat content indexes are closely tracked and often discussed.  When I recently looked at a global map of SL anomalies, they did not appear to be nearly as high/widespread in the other warm areas of the Pacific as they are in the warm EastPac equatorial regions.  Does this imply that The Blob has less staying power and would be more easily disrupted by stormy conditions that mix water from depth?  I know that SL anomalies can be influenced by more than just local SST's, so perhaps looking at those alone is misleading.

Living on the Central California coast, I know that (local) anomalously warm SST are very easily disrupted by our usual NP High winds.  SST's can drop dramatically in just a couple of days when a warm spell is broken by strong winds.  Conversely, it seems to take longer for SST's to warm-up due to lack of winds and persistent sunny weather such as we've had much of this year.  These informal observations have led me to think that warm anomalies are much more easily disrupted than generated.

Is there more data that can help to predict the behavior of The Blob in the face of a strengthening Pacific storm track as we get deeper into the Fall (perhaps that some of the forecasting blogs have missed)?  Is there a reason this aspect hasn't been discussed more?

(back to lurking now!)

[AbruptSLR]

There has been a lot of discussion recently about the staying power of "The Blob" in the face of this year's El Niño event, with various opinions from "inconsequential" to "it will take months and many storms for The Blob to be affected" to "it's not going away" . . . One thing I have not yet seen discussed is the amount (or depth) of heat underlying the SST anomalies outside of the equatorial regions.

For the Niño regions, the SL anomalies and upper ocean heat content indexes are closely tracked and often discussed.  When I recently looked at a global map of SL anomalies, they did not appear to be nearly as high/widespread in the other warm areas of the Pacific as they are in the warm EastPac equatorial regions.  Does this imply that The Blob has less staying power and would be more easily disrupted by stormy conditions that mix water from depth?  I know that SL anomalies can be influenced by more than just local SST's, so perhaps looking at those alone is misleading.

Living on the Central California coast, I know that (local) anomalously warm SST are very easily disrupted by our usual NP High winds.  SST's can drop dramatically in just a couple of days when a warm spell is broken by strong winds.  Conversely, it seems to take longer for SST's to warm-up due to lack of winds and persistent sunny weather such as we've had much of this year.  These informal observations have led me to think that warm anomalies are much more easily disrupted than generated.

Is there more data that can help to predict the behavior of The Blob in the face of a strengthening Pacific storm track as we get deeper into the Fall (perhaps that some of the forecasting blogs have missed)?  Is there a reason this aspect hasn't been discussed more?

(back to lurking now!)

This is a much debated topic (as you state), however, you might want to check-out Robert Scribbler's point of view at:

http://robertscribbler.com/

Extract: "Hothouse Monsters Clash: Godzilla El Nino Pummels Pacific’s Hot Blob


Two climate change spawned monsters are duking it out over thousands of miles of Pacific Ocean waters.

...

And Godzilla, at this point, appears to have the upper hand. And once the Blob goes down there’s nothing to keep what are likely to be some seriously epic storms slamming into the west coast of North America this Fall and Winter. But according to recent science, there’s a high risk that the Blob will creep on back as the Godzilla El Nino retreats during mid to late 2016. And for the West Coast that means high risk of a pretty vicious cycle of drought to flood to drought. A dangerous weather pattern intrinsically related to human-forced climate change."

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has dropped down to -16.2:

[AbruptSLR]

The prospects for a WWB near the International Dateline by Sept 15 2015 are improving per the attached Albany 5S-5N 850-hPa Wind Anom forecast:

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has dropped down to -16.9:

[AbruptSLR]

The linked NOAA article gives a 95% chance that the current El Nino event will last through the boreal winter of 2015-16:

https://www.climate.gov/news-features/blogs/enso/september-2015-el-ni%C3%B1o-update-and-qa

Extract: "The CPC/IRI ENSO forecast says there’s an approximately 95% chance that El Niño will continue through Northern Hemisphere winter 2015-16, gradually weakening through spring 2016. It’s question & answer time!

...

The Blob is not capable of changing the overlying atmospheric pattern in a significant way.  In the Tropics, changes in ocean temperatures can easily lead to changes in the atmosphere above it. But outside of the Tropics, such as over the North Pacific Ocean, the physics are different, so ocean temperatures can’t effectively change the large-scale atmospheric flow or circulation pattern. The amount of heat in the Tropics is an enormous engine that drives rising motion and affects the whole globe’s circulation; the Blob is like a Fisher Price Power Wheel in comparison.

That said, the way that El Niño might affect water temperatures off the West Coast, or how those water temperatures might affect storms that are steered into the area by El Niño, is really hard to tell. As with any forecast, there are a lot of elements at play. However, El Niño is the dominant factor shaping the overall global picture for this winter."

[gideonlow]

Thanks ASLR.  Robert Scribbler is one of the best and most prolific climate-related bloggers . . . His blog, Neven's and several of the threads on this forum are the only ones for which I make sure to read every word! 

The work you guys do is hugely important.

[AbruptSLR]

Thanks ASLR.  Robert Scribbler is one of the best and most prolific climate-related bloggers . . . His blog, Neven's and several of the threads on this forum are the only ones for which I make sure to read every word! 

The work you guys do is hugely important.

Thank you, and note that per my Reply #1071, NOAA officially concurs with Scribbler that a strong El Nino event should push the Blob out of its way.  However, this is still not a guarantee that heavy rains will come to California this winter (but it does increase the likelihood).

[AbruptSLR]

Per the attached plot issued today by the BoM; the 30-day moving average SOI has drifted down to -17.0:

[Buddy]

I have a question for the "scientific sorts" in the group.  I keep hearing that during an El Nino, the Pacific "releases heat" into the atmosphere.

The struggle I have with that...is that I keep thinking that the only way that the ocean can "release heat" into the atmosphere....is IF the surface water is WARMER than the air right above it (whether this occurs in the Arctic...or occurs at the equator....wherever that occurs).

If the surface ocean temperature is 80 degrees F....and the air temperature is 90 degrees F.....the ocean isn't going to be "releasing heat", the atmosphere will be WARMING THE OCEAN slightly.....and the ocean will be "cooling" the atmosphere at the same time. 

Now...IF the ocean temperature is 85 degrees F and the air temperature is 80 degrees F....THEN the ocean WOULD BE "warming the atmosphere.  Wherever there is a difference between the AIR TEMPERATURE and the OCEAN TEMPERATURE...there will always be a "conflict".  If the ocean temperature is cooler than the air temperature....then the ocean will be cooling the air, and the air will be "warming" the ocean.

Now....I understand that the air temperature changes much more quickly than the ocean temperature because water has a much higher capacity to "hold" heat (or cold).  And I also understand that the air temperature changes more quickly...AND...the nighttime heat in the atmosphere is far less than the daytime heat.

But I still have a "problem" (maybe lack of intellect:) with hearing that the ocean "releases heat" during an El Nino......when it "seems" to me that the ocean really just "doesn't cool the atmosphere as much as it usually does" because the SST's are warmer.  Is this just a "semantic" difference I am struggling with?

[Sigmetnow]

Suddenly, the northern tropics are quiet.

No Northern Hemisphere Tropical Cyclones Near Atlantic Season's Peak A First In 38 Years

A funny thing happened as we reached the peak of the Atlantic hurricane season. Not only did the fledgling Atlantic storms (Grace and Henri) die off, but the hyperactive Pacific also went quiet.

Infrared satellite imagery from September 12 showed a few fledgling clusters of convection along the Intertropical Convergence Zone, but no active tropical cyclones, or even a single disturbance meriting extra attention.

http://www.weather.com/storms/hurricane/news/tropics-quiet-atlantic-pacific-sep2015

[AbruptSLR]

I have a question for the "scientific sorts" in the group.  I keep hearing that during an El Nino, the Pacific "releases heat" into the atmosphere.

The struggle I have with that...is that I keep thinking that the only way that the ocean can "release heat" into the atmosphere....is IF the surface water is WARMER than the air right above it (whether this occurs in the Arctic...or occurs at the equator....wherever that occurs).

If the surface ocean temperature is 80 degrees F....and the air temperature is 90 degrees F.....the ocean isn't going to be "releasing heat", the atmosphere will be WARMING THE OCEAN slightly.....and the ocean will be "cooling" the atmosphere at the same time. 

Now...IF the ocean temperature is 85 degrees F and the air temperature is 80 degrees F....THEN the ocean WOULD BE "warming the atmosphere.  Wherever there is a difference between the AIR TEMPERATURE and the OCEAN TEMPERATURE...there will always be a "conflict".  If the ocean temperature is cooler than the air temperature....then the ocean will be cooling the air, and the air will be "warming" the ocean.

Now....I understand that the air temperature changes much more quickly than the ocean temperature because water has a much higher capacity to "hold" heat (or cold).  And I also understand that the air temperature changes more quickly...AND...the nighttime heat in the atmosphere is far less than the daytime heat.

But I still have a "problem" (maybe lack of intellect:) with hearing that the ocean "releases heat" during an El Nino......when it "seems" to me that the ocean really just "doesn't cool the atmosphere as much as it usually does" because the SST's are warmer.  Is this just a "semantic" difference I am struggling with?

Buddy,

I am a civil engineer, and the issue that you raise is sufficiently complex that denialist can create doubts about this matter, so if I add confusion to this matter please excuse me in advance & hopefully DO can add some clarity next week.

That said, the first attached image by Lee et al 2015, shows that during negative PDO periods (as during the recently ended faux hiatus) there are more & stronger La Nina events that contribute to strong trade winds that stock-up so much water ocean water in the Western Tropical Pacific (the Warm Pool) that it leaks through Indonesia and pours into the Southern Ocean (which has been heating faster than any other ocean in the world).  One of the major reasons why the trade winds get reinforced is because there is a warm to cool/west to east gradient in the Tropical Pacific to begin with. If all of the warmest water is forced to the west by the trade winds, then the surface pressures there are lower, since warmer, moist air has the tendency to rise, which decreases the surface pressure. In order to balance out the rising air and subsequent lowering of surface pressure, air from higher pressure (cold waters to the east where sinking motions are more prevalent) has to flow towards that area in the west. If that Tropical Pacific Ocean thermal gradient is stronger, there is more of an imbalance, meaning the flow of air towards that warmer western water would increase — meaning stronger trade winds. But a weakening of the gradient (due to an Equatorial Kelvin Wave, EKW, trigger in the ocean by westerly wind bursts, WWBs) weakens this imbalance, which weakens the warm water flow towards the west. This serves to slow the trade winds. Thus during an El Nino event, the trade winds slowing helps more warm water to push eastward to begin with via EKWs and westerly wind bursts — so this warm water also downwells — and by the time it upwells further east, it is relatively warm, reinforcing the warm SST anomaly that weakened the gradient and weakened the trade winds to begin with. The cycle is continuous, and a Bjerknes feedback is generated (see the second attached image).

By this line of reasoning you can see that more La Nina events (during negative PDO phases) sequester more heat into the Southern Ocean; while more El Nino events (during positive PDO/IPO phases and also with more Global Warming), you can see that more warm surface water is left in the Eastern Tropical Pacific Ocean.  However (as I said previously) warmer ocean surface is a larger vapor-pressure difference between the sea surface and the adjacent atmosphere, resulting in more evaporation, and more up-drafting (upward convection) of warm moist air into the upper atmosphere (particularly near the equatorial International Dateline as shown in the third image, but also from the Eastern Equatorial Pacific as shown in the fourth image).

Thus you can see that the transfer of energy from the ocean to the atmosphere during strong El Nino events is dominated by how easily water evaporates from the ocean (which is dominating by the temperature of the water) and not by direct heat transfer from an ocean that is warmer than the atmosphere.

Best,
ASLR

[AbruptSLR]

The two images were issued today by the University at Albany with forecasts from Sept 12 to 19 2015 from 5S to 5N for the 850-hPa Wind Anom and the 200-hPa Wind Anom, respectively.  The first figure shows that starting tomorrow the forecasted WWB is strengthening, while the second image confirms that Bjerknes feedback is still working to strengthen El Nino condtions.

[AbruptSLR]

The first image from Sept 4 2015 shows that the EKW has progressively moved eastward as compared to the second image from August 20 2015.  Both images show the Jason-2 observed sea surface residuals.

[AbruptSLR]

Per the following data and the attached plot issued today by the BoM, the 30-day moving average SOI has moved down to -17.7:

20150813,20150911,-17.7

[oren]

I have a question for the "scientific sorts" in the group.  I keep hearing that during an El Nino, the Pacific "releases heat" into the atmosphere.

The struggle I have with that...is that I keep thinking that the only way that the ocean can "release heat" into the atmosphere....is IF the surface water is WARMER than the air right above it (whether this occurs in the Arctic...or occurs at the equator....wherever that occurs).

If the surface ocean temperature is 80 degrees F....and the air temperature is 90 degrees F.....the ocean isn't going to be "releasing heat", the atmosphere will be WARMING THE OCEAN slightly.....and the ocean will be "cooling" the atmosphere at the same time. 

Now...IF the ocean temperature is 85 degrees F and the air temperature is 80 degrees F....THEN the ocean WOULD BE "warming the atmosphere.  Wherever there is a difference between the AIR TEMPERATURE and the OCEAN TEMPERATURE...there will always be a "conflict".  If the ocean temperature is cooler than the air temperature....then the ocean will be cooling the air, and the air will be "warming" the ocean.

Now....I understand that the air temperature changes much more quickly than the ocean temperature because water has a much higher capacity to "hold" heat (or cold).  And I also understand that the air temperature changes more quickly...AND...the nighttime heat in the atmosphere is far less than the daytime heat.

But I still have a "problem" (maybe lack of intellect:) with hearing that the ocean "releases heat" during an El Nino......when it "seems" to me that the ocean really just "doesn't cool the atmosphere as much as it usually does" because the SST's are warmer.  Is this just a "semantic" difference I am struggling with?

buddy,
I am a civil engineer, and the issue that you raise is sufficiently complex that denialist can create doubts about this matter, so if I add confusion to this matter please excuse me in advance & hopefully DO can add some clarity next week.

That said, the first attached image by Lee et al 2015, shows that during negative PDO periods (as during the recently ended faux hiatus) there are more & stronger La Nina events that contribute to strong trade winds that stock-up so much water ocean water in the Western Tropical Pacific (the Warm Pool) that it leaks through Indonesia and pours into the Southern Ocean (which has been heating faster than any other ocean in the world).  One of the major reasons why the trade winds get reinforced is because there is a warm to cool/west to east gradient in the Tropical Pacific to begin with. If all of the warmest water is forced to the west by the trade winds, then the surface pressures there are lower, since warmer, moist air has the tendency to rise, which decreases the surface pressure. In order to balance out the rising air and subsequent lowering of surface pressure, air from higher pressure (cold waters to the east where sinking motions are more prevalent) has to flow towards that area in the west. If that Tropical Pacific Ocean thermal gradient is stronger, there is more of an imbalance, meaning the flow of air towards that warmer western water would increase — meaning stronger trade winds. But a weakening of the gradient (due to an Equatorial Kelvin Wave, EKW, trigger in the ocean by westerly wind bursts, WWBs) weakens this imbalance, which weakens the warm water flow towards the west. This serves to slow the trade winds. Thus during an El Nino event, the trade winds slowing helps more warm water to push eastward to begin with via EKWs and westerly wind bursts — so this warm water also downwells — and by the time it upwells further east, it is relatively warm, reinforcing the warm SST anomaly that weakened the gradient and weakened the trade winds to begin with. The cycle is continuous, and a Bjerknes feedback is generated (see the second attached image).

By this line of reasoning you can see that more La Nina events (during negative PDO phases) sequester more heat into the Southern Ocean; while more El Nino events (during positive PDO/IPO phases and also with more Global Warming), you can see that more warm surface water is left in the Eastern Tropical Pacific Ocean.  However (as I said previously) warmer ocean surface is a larger vapor-pressure difference between the sea surface and the adjacent atmosphere, resulting in more evaporation, and more up-drafting (upward convection) of warm moist air into the upper atmosphere (particularly near the equatorial International Dateline as shown in the third image, but also from the Eastern Equatorial Pacific as shown in the fourth image).

Thus you can see that the transfer of energy from the ocean to the atmosphere during strong El Nino events is dominated by how easily water evaporates from the ocean (which is dominating by the temperature of the water) and not by direct heat transfer from an ocean that is warmer than the atmosphere.

Best,
ASLR

Although I didn't ask the original question, thank you ASLR for the very clear explanation.

[Pmt111500]

I have a question for the "scientific sorts" in the group.  I keep hearing that during an El Nino, the Pacific "releases heat" into the atmosphere.

The struggle I have with that...is that I keep thinking that the only way that the ocean can "release heat" into the atmosphere....is IF the surface water is WARMER than the air right above it (whether this occurs in the Arctic...or occurs at the equator....wherever that occurs).

The simplistic explanation would be that the ocean is at the higher temperature than the atmosphere, during the night, so that possibly clears some confusion. But I guess you're looking for a more complete version of this. It's mainly a question of the areal extent of SST anomalies during ENSO phases in the Tropical Pacific. This of course doesn't automatically mean surface temperatures of the whole world will go up but since there hasn't been any Dansgaard-Öscher-like events in the instrumentally recorded past it can be said ENSO is the primary modulator of the temperature in the lowest atmosphere... Likely there are some other related things that contribute to this like the west wind bursts changing the composition and occurrence of ITCZ clouds in the affected area. Good question is how much do the westerly bursts contribute to the intensity of el Nino.

[seaicesailor]

I've been hearing people like to compare this El Nino to the huge one that developped 1997. Here presented side by side is the sea surface temperatures of last weeks of august and I'd say 2015 still has some way to go to be called a huge one. More notable is the relative heat in the Southern Indian Ocean and North Pacific, and the cold blob of the North Atlantic. Yes the temperatures over at Nino region are pretty same though 1997 was more widespread at this stage. Compared to the temperatures elsewhere in the world ocean this is not a huge one.

What you imply is that the increase of global SST average between 1997 to 2015 is not well removed from current anomalies? I believe global warming is taken into account and data are detrended to show correct deviations....
Either way, it is disconforting reality.

There are other indicators such as the slope of the thermocline (which I think shows heat imbalance along the equator rather than a temperature anomaly) that should help determine the relative strength of this El Nino, but people here will know better.

[AbruptSLR]

There are other indicators such as the slope of the thermocline (which I think shows heat imbalance along the equator rather than a temperature anomaly) that should help determine the relative strength of this El Nino, but people here will know better.

The first image from NOAA for modeled conditions on Sept 5 2015 shows: (a) in the upper panel the Subsurface Temperature Anom that highlights the current EKW's position/strength; and (b) the lower panel shows the depth of the thermocline associated with the current EKW. 

It is important to note that EKWs represent the downwelling phases (indicated by the dashed lines in the second image of the Eq Pac Upper Ocean Heat Anom Evolution issued Sept 7 2015) of the multiple oceanic oscillations that gradually build-up an El Nino (or a La Nina) event.  Furthermore, note that in the second image the dotted lines indicate the upwelling phases of the multiple oceanic EKW oscillations.  The downwelling phases lower the depth of the thermocline in the Eastern Eq. Pac, while the upwelling phases (of the multiple oceanic EKW oscillation) raise the depth of thermocline.  This is important for defining the occurrence of a strong El Nino event, because when the thermocline is low enough in the Eastern Eq Pac during the downwelling phase, then when the upwelling phase occurs, it will raise-up warm water and not cool water; which creates a positive feedback mechanism for strengthening the El Nino event (ie if the thermocline is not low enough then the upwelling phase will raise-up cool water which will promote trade wind activity that will reduce EKW activity and may lead to a La Nina).

As can be seen in the first image, the current EKW will soon lower the depth of the thermocline all the way to South America; which means that the next upwelling phase (see the second image) should raise-up still warmer water than during the last oscillation; which would mean that our current El Nino event is likely to get stronger in October, than it is now.

[AbruptSLR]

The attached image issued today by the University at Albany of the 5S-5N 850-hPa Wind Anom forecast from Sept 13 to 20 2015, shows that the forecasted WWB is stronger than what was forecast yesterday.

[AbruptSLR]

Per the following data and attached plot issued today by the BoM, the 30-day moving average SOI has drifted down to -17.8:

20150814,20150912,-17.8

[Pmt111500]

I've been hearing people like to compare this El Nino to the huge one that developped 1997. Here presented side by side is the sea surface temperatures of last weeks of august and I'd say 2015 still has some way to go to be called a huge one. More notable is the relative heat in the Southern Indian Ocean and North Pacific, and the cold blob of the North Atlantic. Yes the temperatures over at Nino region are pretty same though 1997 was more widespread at this stage. Compared to the temperatures elsewhere in the world ocean this is not a huge one.

What you imply is that the increase of global SST average between 1997 to 2015 is not well removed from current anomalies? I believe global warming is taken into account and data are detrended to show correct deviations....
Either way, it is disconforting reality.

There are other indicators such as the slope of the thermocline (which I think shows heat imbalance along the equator rather than a temperature anomaly) that should help determine the relative strength of this El Nino, but people here will know better.

I didn't check it but the two images are from the same site and it would be odd if they used a different baseline period for historical SSTs and for this year. There could be better measures of ENSO strength that are used somewhere, but removing the effect of GW would have to happen afterwards, thus making such measure hard to use concurrently. The slope of the thermocline over the Pacific would be a good measure, yes, but I don't know how people measure it for timely analysis.

[bigB]

ASLR,

Check out the latest IOD index value from the BOM. It seems very likely that we are headed for an official +IOD event. If the current trend continues,  the +IOD will likely begin reinforcing El Nino by further suppressing convection over the Maitime Continent.

[deep octopus]

Over the last week, the Niño 3.4 region warmed to 2.3 C, while the Niño 3 region warmed to 2.6 C, indicating new peaks in these regions during this ENSO cycle and the strongest reads since February 1998.

                Nino1+2      Nino3        Nino34        Nino4
 Week          SST SSTA     SST SSTA     SST SSTA     SST SSTA
 05AUG2015     23.6 2.6     27.6 2.3     28.9 1.9     29.6 0.9
 12AUG2015     22.8 2.0     27.3 2.2     28.9 2.0     29.6 0.9
 19AUG2015     22.4 1.7     27.2 2.2     28.9 2.1     29.7 1.1
 26AUG2015     22.6 2.0     27.3 2.3     29.0 2.2     29.7 1.1
 02SEP2015     22.7 2.2     27.3 2.4     28.9 2.1     29.7 1.0
 09SEP2015     22.5 2.0     27.4 2.6     29.0 2.3     29.7 1.0

Attached is the SST anomaly chart by OSPO for September 14, 2015.

[AbruptSLR]

ASLR,

Check out the latest IOD index value from the BOM. It seems very likely that we are headed for an official +IOD event. If the current trend continues,  the +IOD will likely begin reinforcing El Nino by further suppressing convection over the Maitime Continent.

bigB,

Thanks for the heads-up, I am so use to checking for updates to the BoM's weekly indices on Tuesday that I am surprised that they have now posted values through Sept 13 2015 today (Monday).  Indeed, the first image of the IOD at +0.97 is eye catching, and very likely foretells a further strengthening of the current El Nino.  The second image shows that the BoM has the Nino 3.4 index back up to +1.96 (they seem to use a different standard than NOAA).

The third image from the BoM shows that the equatorial cloud cover near the international dateline is abnormally high (which supports convection there); and the fourth NOAA image issued Sept 14 2015 of the Evolution of the Eq. Pac. Upper Ocean Heat Anom, shows that the current downwelling phase of the EKW oscillation remains strong as it approaches South America, and thus the upwelling phase will likely bring up relatively warm water, thus also foretelling likely further strengthening of our current El Nino in October.

Best,
ASLR

[AbruptSLR]

Today the BoM issued the accompanying weekly plots through the week ending Sept 13 2015 for the Nino 1, 2, 3 & 4 indices, respectively.  In general terms these values indicate that the current downwelling phase of the EKW oscillation is about to peak, and that further oscillation in the ENSO cycle will likely strengthen our current El Nino this fall.

[AbruptSLR]

The two attached plots are from the CPC/IRI early September 2015 summary report, showing, respectively, a summary of the Nino 3.4 forecast (showing a strong likelihood of the current El Nino event lasting until the boreal spring of 2016), and a plot of the June-August 2015 land surface temperature rankings showing that 2015 has been the hottest boreal summer on record.

[Lord M Vader]

According to latest report from NOAA, the PDO dropped somewhat in August and virtually on pair with April.

See:

Courtesy: NOAA

[AbruptSLR]

In the way of a status update:

The first image shows the NOAA projected Subsurface temperature and temp. anom. for Sept 10 2015, showing that the EKW is still strong.

The second image by NOAA shows the Eq Pac. Upper Ocean Heat Anom circa Sept 10 to 14 2015, showing that anom has plateaued and may (or may not) start increasing again with the next EKW pulse.

The third image by NOAA shows the SSTA for Sept 14 2015, showing that residual cool surface temp anoms off the coast of Ecuador are beginning to break-up as the EKW surfaces.

The fourth image of the UofA 850-hPa Wind Anom forecast from Sept 14 to 21 2015, shows that we have now begun a period of a moderate WWB near the equatorial international dateline.

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has drifted down to -17.9:

[AbruptSLR]

The following is an extract from BoM's ENSO Wrap-up:

Extract: "A strong El Niño and record warm Indian Ocean continue

Issued on 15 September 2015  | Product Code IDCKGEWW00

El Niño continues to strengthen. Recent oceanic and atmospheric indicators are at levels not seen since the 1997–98 El Niño. Persistently weak or reversed trade winds and a strongly negative Southern Oscillation Index (SOI), in conjunction with the ongoing warming in the tropical Pacific Ocean, indicate the El Niño is unlikely to end before early 2016.

Climate models indicate sea surface temperatures in the central tropical Pacific are likely to rise further over the next few months, coming close to, or possibly exceeding, monthly values observed during the 1997–98 event. All models suggest the event will peak around the end of the year, followed by rapid weakening heading into autumn 2016. It is too early to accurately determine the likely pattern beyond autumn, but a continued El Niño is considered the least likely outcome at this stage.

Temperature patterns in the Indian Ocean are continuing to have a strong influence on Australian climate. The whole Indian Ocean remains warmer than average with sea surface temperatures in the southern Indian Ocean the highest on record for winter. Some localised cooling near Indonesia means the Indian Ocean Dipole (IOD) index has been above the +0.4 °C threshold for six weeks. If this continues for at least another fortnight, this will be considered a positive IOD event. Most models indicate this is likely."

Edit: The attached TAO subsurface temperature plot shows that the current EKW is strong

[AbruptSLR]

Per the University of Washington the August PDO has dropped down to just above its June 2015 value:

YEAR   JAN    FEB    MAR   APR    MAY   JUN     JUL    AUG    SEP    OCT    NOV    DEC
2014   0.30   0.38   0.97   1.13   1.80   0.82   0.70   0.67   1.08   1.49   1.72   2.51
2015   2.45   2.30   2.00   1.44   1.20   1.54   1.84  1.56

[bigB]

The following graph shows monthly equatorial upper 300m temp anomalies between 180-100W for January-December 1982, 1986, 1987, 1991, 1997, 2002, 2009, and January-August 2015. The dataset used comes from NOAA (see link below) and begins in 1979. Only moderate-strong El Ninos were used for this analysis. Looking at this graph, we can see that: (a) positive equatorial upper ocean heat anomalies have remained strong since March 2015, indicating enhanced downwelling Kelvin wave activity and much suppressed upwelling Kelvin wave activity, (b) equatorial upper ocean heat anomalies for August 2015, were stronger than any other El Nino since at least 1979, and (c) there's still a massive amount of heat largely associated with the 3rd downwelling Kelvin wave that has yet to discharge to the surface (even as of Sep 10th, per the weekly data provided in ASLR's reply #1094). While the 3rd downwelling Kelvin wave did begin surfacing in late August, what we've seen so far has only been the tip of the iceberg. It looks to me like the bulk of the 3rd downwelling Kelvin wave will surface late September through mid October. That's just speculation though, as this Kelvin wave has behaved differently than other recently observed Kelvin waves, thus making it difficult to predict when peak eruption will occur (at least for me). It's interesting to note that even though 1986 and 1987 were strong El Nino years, equatorial upper ocean heat anomalies were relatively weak (compared to the strength of SSTA). This is something that has always baffled me.

Data source: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt

[AbruptSLR]

Per the attached plot issued today by the BoM, the 30-day moving average SOI has moved down to -18.1:

[Pmt111500]

The following graph shows monthly equatorial upper 300m temp anomalies between 180-100W for January-December 1982, 1986, 1987, 1991, 1997, 2002, 2009, and January-August 2015. The dataset used comes from NOAA (see link below) and begins in 1979. Only moderate-strong El Ninos were used for this analysis. Looking at this graph, we can see that: (a) positive equatorial upper ocean heat anomalies have remained strong since March 2015, indicating enhanced downwelling Kelvin wave activity and much suppressed upwelling Kelvin wave activity, (b) equatorial upper ocean heat anomalies for August 2015, were stronger than any other El Nino since at least 1979, and (c) there's still a massive amount of heat largely associated with the 3rd downwelling Kelvin wave that has yet to discharge to the surface (even as of Sep 10th, per the weekly data provided in ASLR's reply #1094). While the 3rd downwelling Kelvin wave did begin surfacing in late August, what we've seen so far has only been the tip of the iceberg. It looks to me like the bulk of the 3rd downwelling Kelvin wave will surface late September through mid October. That's just speculation though, as this Kelvin wave has behaved differently than other recently observed Kelvin waves, thus making it difficult to predict when peak eruption will occur (at least for me). It's interesting to note that even though 1986 and 1987 were strong El Nino years, equatorial upper ocean heat anomalies were relatively weak (compared to the strength of SSTA). This is something that has always baffled me.

Data source: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt

Thanks, that's a cool chart, Big B, may I try to modify this? Thanks for the data source, this might be useful elsewhere too.

[Lord M Vader]

Interesting things are going on in the Pacific!

Of most interest I find:

1) the recent cooling in the far Eastern Pacific. (See CDAS SSTA change during the last 7 days and Niño 1+2 area at Tropical Tidbits http://www.tropicaltidbits.com/analysis/ocean.html). To me it seems that the trade winds are eliminating the surfacing of our current EKW. This is somewhat evident by PMEL/TAO from NOAA which shows some easterlies present in the far Eastern Pacific.

2) If current cooling trend continues in the Niño 1+2 area, which the latest GFSv2 forecast from NOAA shows, would this imply a hybrid of a very strong "Modoki El Niño"/classical El Niño? See: http://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2seasonal.shtml

3) The forecast from NOAA/CPC wrt the Niño 1+2 is interesting as it shows a decrease in the anomalies for the next months. BUT! By April 2016 the CPC/NOAA forecast hints of a possible surge upward in this area. Is that normal if an El Niño is going to fade out or would that imply something else?

ASLR, BigB and Doc Oc - what are your ideas about the whole thing?

Best, LMV