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hurricaneman

2015 ENSO super thread

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The ENSO Region 1+2 anomaly has now risen to +3.3°C, which is 0.5°C below the 1997 figure for near this date. More importantly, that figure is 0.8°C above what has been modeled by the CFSv2,with the most recent run having moved the forecast peak from June to July.  This region is very fickle and can undergo dramatic cooling, but with the CFSv2 missing badly on the current peak, it's perhaps more likely than not that the model's forecasts for this region are too cool for the weeks ahead.

 

A basin-wide El Niño event is very likely the base case for this winter. Among the El Niño events that approached or reached strong status, only 2009-10 was a Central Pacific-oriented event. 1957-58, 1965-66, 1972-73, and 1991-92 were basin-wide events. Both super El Niño events (1982-83 and 1997-98) were basin-wide events.

 

It's still too soon to know whether the winter will feature one or more months with ENSO Region 1+2 anomalies of +1.0°C or above. Both super El Niños did, and a super El Niño event remains a distinct possibility.

 

Extrapolations from this far out are very difficult, so aside from having some degree of confidence in a strong event--Region 3.4 has now reached the strong threshold (though we'll have to see if it is sustained on a monthly and tri-monthly basis)--its full strength remains far from certain. Therefore, winter predictions are also premature.

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Still much cooler than 1997 in the subsurface layer:

 

lll.png

Absolutely, though as I mentioned a week or so ago in the other thread, there's an opportunity for 2015 to play catch-up in this department. 1997 was flying high at this point off the massive June WWB of that year, but the trades re-established until August, causing significant weakening of the subsurface anomalies by the end of July.

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TAO buoys are now showing rapid and deep subsurface warming in the 180-150W area in association with the latest EKW.

Also, there is an extremely powerful ongoing wwb, so we are about a month behind 1997. The massive wwb hapened in June that year, this year, it's happening in July

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Still much cooler than 1997 in the subsurface layer:

 

lll.png

Is that +9C on the 1997 chart? Holy cow!!!

 

We might catch up some but doesn't look like we have enough juice underneath to reach 97-98 levels. The westerly winds will allow some of the warm pool to surface but won't necessarily have that big of an effect on subsurface anomalies. It's sort of like, no matter how hard I hit the gas in our small Honda Fit, the car's not going to go that fast.

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I put together these charts of 850mb trade wind index and SST anomalies based off data from NOAA.  I chose to use a 4 month running mean for the trade wind charts to smooth out the numbers.  For background if needed, the negative trade wind index anomaly values indicate where the east to west blowing trade winds are weaker than normal, or have reversed and are blowing west to east, a hallmark of El Nino.  

 

A couple of things stand out to me: 1) the pattern of the Central Pacific trade wind index anomaly graphs (2nd chart) closely mirrors the monthly SST anomaly graphs (3rd chart), but with reverse sign.  I suppose once the warm pool (SST) has moved out of the west Pacific toward the dateline (as is currently the case), the final push to substantially raise the Nino 3.4 SSTs comes from westerly wind anomalies that have pressed east of the dateline.  With the recent early July westerly wind burst, we’ve seen noteworthy westerly wind anomalies press east of the dateline for the first time this year (4th chart)….and 2) the charts overall reinforce the idea that the base starting point for this El Nino is high, so there’s not as much of a mountain to climb with the warming. 

 

A super nino appears to be within reach (ONI), but I suspect that whether or not it gets there is largely dependent on how strong, how persistent, and how far east the westerly wind anomalies build...and as we've seen in the past, predicting the specifics of ENSO is very difficult.

 

850_Anoms_and_SST.gif
 

850.gif

 

 

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A quick note for those who may find the Region 3.4 figures graphed above lower than what NOAA has reported e.g., most recently +1.5°C in its weekly report:

 

NOAA is using the OISST.v2 data set in its ENSO analyses. The models e.g., ECMWF, are also still based on that data set. The ERSSTv4 data set is new. The GISS global land and ocean temperature anomalies have just incorporated the newer data set.

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A quick note for those who may find the Region 3.4 figures graphed above lower than what NOAA has reported e.g., most recently +1.5°C in its weekly report:

 

NOAA is using the OISST.v2 data set in its ENSO analyses. The models e.g., ECMWF, are also still based on that data set. The ERSSTv4 data set is new. The GISS global land and ocean temperature anomalies have just incorporated the newer data set.

 

Don - yeah it is odd that varying data sets are used for SSTs, though I'm sure there are valid reasons for it.  Just a note that NOAA uses the ERSSTv4 data set for ONI calculations, which is why I used it in the graph.

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Don - yeah it is odd that varying data sets are used for SSTs, though I'm sure there are valid reasons for it.  Just a note that NOAA uses the ERSSTv4 data set for ONI calculations, which is why I used it in the graph.

I agree. I saw the label on the chart, so I knew that you were using the newer data set. Hopefully, it won't be long before a common data set is again being used.

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+3.0˚ anomaly Nino would be simply unreal. The mean of that itself is already in the super Nino class being somewhere around +2.2-2.3˚.

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Excuse my basic question but would it be prudent to watch the current SST anomalies along pacific coast (NW pacific) closely , currently the anomalies are favorable for a winter ridge are they not ? Meaning the + precip anomalies associated with a niño could be a tad further south if that persists as the jet could be a bit further south than the "ave" niño (thanks to SST) anomalies.

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Excuse my basic question but would it be prudent to watch the current SST anomalies along pacific coast (NW pacific) closely , currently the anomalies are favorable for a winter ridge are they not ? Meaning the + precip anomalies associated with a niño could be a tad further south if that persists as the jet could be a bit further south than the "ave" niño (thanks to SST) anomalies.

 

The SSTA's in this area have gotten a lot of attention the last few years. In a lot of ways it's a chicken and egg discussion. Pattern persistence drives SSTA's. Is there a feedback mechanism back into the atmosphere once substantial anomalies are in place? Probably safe to say yes but only to an extent. And things can reverse faster than many realize. 

 

Here's July 2014 SSTA's. GOA region was roasting. 

 

anomnight.7.17.2014.gif

 

 

 

By the end of September 2014 the anomalies had relaxed some but were still solid. 

 

anomnight.9.29.2014.gif

 

 

 

Then October came along with a very strong and persistent low height anomaly over much of the warm anomalies. 

 

post-2035-0-44819100-1437496307_thumb.jp

 

 

SSTA's responded quickly in just 30 days. 

 

anomnight.10.30.2014.gif

 

 

However, the pattern reversed in Nov with the low height anoms retrograding to south of the Aleutians and + anoms covering the GOA (and up through AK). Had the October pattern persisted through November, most if not all of the + ssta's in the GOA would have been wiped out. 

 

There are varying opinions on this topic. My personal opinion is that warm anoms in the GOA region during the summer/ early fall don't necessarily tell us anything about ridge placement down the line. Once we get to Nov-Dec things become a little more clear obviously. 

 

I looked back at previous stronger nino events and the base state of the epo is mixed practically 50/50 during DJF. Not much to be gleaned there but the data set is too small to overthink anyways. 

 

One thing is for sure...relying on the PAC for a 3rd year in a row to overcome a damn persistent +ao/nao base state is something that doesn't give me any warm and fuzzies. Interior regions along the EC may survive but folks closer to the coast could be in trouble. 

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Great point, Bob.  The one think you can bank on this year is a pretty strong southern stream.  Aside from a few Feb-March events in recent years, the SJS has been MIA the first half of the winter.  Ridge placement will obviously be determined by the basin type of nino this is and that damn persistent GOA warm pool.  I'm with you though, the east based look of this nino is given me the shakes at this early stage.  

 

As far as the NAO is concerned- we may be heading into a more -NAO base state based on the last month or two.  Definitely a lot more negative values showing up this summer versus the winter.

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Great point, Bob.  The one think you can bank on this year is a pretty strong southern stream.  Aside from a few Feb-March events in recent years, the SJS has been MIA the first half of the winter.  Ridge placement will obviously be determined by the basin type of nino this is and that damn persistent GOA warm pool.  I'm with you though, the east based look of this nino is given me the shakes at this early stage.  

 

As far as the NAO is concerned- we may be heading into a more -NAO base state based on the last month or two.  Definitely a lot more negative values showing up this summer versus the winter.

 

Thankfully the overall SST config in the PAC looks a good bit different than 97-98. Especially in the PDO region. That could give us some clues where the low height anomaly persists in the npac. Keep it close to the aleutians and we won't exclusively roast and rain at least. 97-98 was completely overwhelmed by the persistent and strong vortex wobbling around the NE pac.

 

Oddly though, between the last 3 strong events (72-73, 82-83, 97-98), 97-98 featured the best overall nao state. But it made no difference. 82-83 looks kinda crappy on paper numerically but things lined up a couple times for some big impact events in the MA. 

 

I'm rooting for a strong event combined with a stout +pdo and just letting the chips fall. If it rains in my yard so be it. I want to watch some big miller A's roll up the coast. They've been largely absent since 09-10. I don't count Feb 2014. It was too strung out and weird even though it produced. 

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soi minimums ...todays was -00.06

day.....1997...2015 soi minimums...

086...-38.04..........076...-35.90

101...-38.78..........098...-31.15

124...-37.85..........129...-46.94

143...-41.87..........135...-33.15

151...-85.72..........143...-17.75

162...-49.99..........156...-04.71

168...-61.70..........166....10.75

180...-21.54..........177...-48.73

188....02.84..........188....13.48

197...-09.84..........197...-31.46

204...-34.78..........202...-00.06

233...-33.88

260...-26.63

278...-32.98

308...-56.59

331...-44.58

032...-77.60

093...-52.94

120...-53.83

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