2014 ENSO Mega Thread

[AvantHiatus]

1C isn't a strong El Nino. Why wouldn't we count 2009 as a strong one?

[roardog]

I guess I don't understand your point

[AvantHiatus]

I guess I don't understand your point

The difference compared to 97-98 is substantial and the time allocated above strong threshold is not enough for 09-10 to be classified as a strong event.

[roardog]

The difference compared to 97-98 is substantial and the time allocated above strong threshold is not enough for 09-10 to be classified as a strong event.

I believe 09-10 peaked at 1.6 which is a strong El Nino.

[StudentOfClimatology]

2009/10 was definitely a strong Nino. If the 2013/14 El Nino qualifies as strong, it'll be only the time we've had two strong Ninos within 5 years in a -PDO phase since accurate measurements began in 1950. So statistics argue caution.

[AvantHiatus]

I believe 09-10 peaked at 1.6 which is a strong El Nino.

I disagree, 09-10 was a borderline moderate/strong event.

[Yellow Evan]

1C isn't a strong El Nino. Why wouldn't we count 2009 as a strong one?

 

It's not. I didn't say this upcoming one was for certain, I said it could very well happen (a strong El Nino).

 

Re: 2009, I read on another board it was not per http://oi58.tinypic.com/aewapw.jpg . But I've seen it listed as a strong El Nino, so it's debatable. But even then, it'd been a while since we've had an El Nino.

[griteater]

2009/10 was definitely a strong Nino. If the 2013/14 El Nino qualifies as strong, it'll be only the time we've had two strong Ninos within 5 years in a -PDO phase since accurate measurements began in 1950. So statistics argue caution.

 

As evidenced by the varying posts on the subject, there's no clear cut definition of weak / moderate / strong ENSO.  From an ONI perspective, I personally like the method used on this website by Jan Null (same site where I believe weatherguy pulled the graph posted above) - http://ggweather.com/enso/oni.htm.  Using this method, in order for a Nino to be classified as strong, the ONI would have to be +1.5 or higher for at least 3 consecutive tri-monthly periods.  2009-2010 peaked at +1.4 / +1.6 / +1.6, just missing the mark for strong Nino designation, using this method.  To take it a step further, I think it's also prudent to factor in MEI rankings - http://www.esrl.noaa.gov/psd/enso/mei/rank.html.  The MEI rankings are computed using bi-monthly periods.  So, if we use similar logic as what is shown on Jan Null's site, in order for a Nino to be classified as strong, the MEI rankings would have to be in the strong category for 4 consecutive bi-monthly periods.  2009-2010 achieved strong Nino designation in only 2 consecutive bi-monthlies using the MEI rankings.  All of the following Ninos had at least 4 consecutive bi-monthly MEI rankings in the strong range: 97-98, 91-92, 82-83, 72-73, 65-66, 57-58

[Dsnowx53]

The daily SOI is back to being negative (-0.36) and has been trending in that direction for the past several days. The pressures at Tahiti have been falling. The daily SOI jumps around a lot, so this doesn't mean much yet. 

 

http://www.longpaddock.qld.gov.au/seasonalclimateoutlook/southernoscillationindex/30daysoivalues/

[StudentOfClimatology]

As evidenced by the varying posts on the subject, there's no clear cut definition of weak / moderate / strong ENSO. From an ONI perspective, I personally like the method used on this website by Jan Null (same site where I believe weatherguy pulled the graph posted above) - http://ggweather.com/enso/oni.htm. Using this method, in order for a Nino to be classified as strong, the ONI would have to be +1.5 or higher for at least 3 consecutive tri-monthly periods. 2009-2010 peaked at +1.4 / +1.6 / +1.6, just missing the mark for strong Nino designation, using this method. To take it a step further, I think it's also prudent to factor in MEI rankings - http://www.esrl.noaa.gov/psd/enso/mei/rank.html. The MEI rankings are computed using bi-monthly periods. So, if we use similar logic as what is shown on Jan Null's site, in order for a Nino to be classified as strong, the MEI rankings would have to be in the strong category for 4 consecutive bi-monthly periods. 2009-2010 achieved strong Nino designation in only 2 consecutive bi-monthlies using the MEI rankings. All of the following Ninos had at least 4 consecutive bi-monthly MEI rankings in the strong range: 97-98, 91-92, 82-83, 72-73, 65-66, 57-58

Thanks, nice post. I prefer to average the peak in the ONI over the 3 months, which comes out to 1.55. It's semantical either way, as 2009-10 was not a "super niño" by any means.

But it was the strongest west-based El Niño since official records began, and was marked by anomalous circulations around the globe. So I personally consider it a strong niño, as opposed to events like 2002-03 and 2006-07 which never had that "oomph" factor in the tropics.

[JBG]

2009/10 was definitely a strong Nino. If the 2013/14 El Nino qualifies as strong, it'll be only the time we've had two strong Ninos within 5 years in a -PDO phase since accurate measurements began in 1950. So statistics argue caution.

1965-6 to 1972-3 came close, especially if you consider 1968-70 to be an extension of 1965-6.  We only got to cold-neutral in between 1965-6 and 1968-70.

[Dsnowx53]

Thanks, nice post. I prefer to average the peak in the ONI over the 3 months, which comes out to 1.55. It's semantical either way, as 2009-10 was not a "super niño" by any means.

But it was the strongest west-based El Niño since official records began, and was marked by anomalous circulations around the globe. So I personally consider it a strong niño, as opposed to events like 2002-03 and 2006-07 which never had that "oomph" factor in the tropics.

 

 

I feel the same way. 

[griteater]

Steady warming across the equatorial Pacific over the past 3 months.  Also, the April PDO reading on the Univ. of Washington site came in at 1.13.  That's the highest reading since June 2005

 

[JBG]

 

Thanks, nice post. I prefer to average the peak in the ONI over the 3 months, which comes out to 1.55. It's semantical either way, as 2009-10 was not a "super niño" by any means.

But it was the strongest west-based El Niño since official records began, and was marked by anomalous circulations around the globe. So I personally consider it a strong niño, as opposed to events like 2002-03 and 2006-07 which never had that "oomph" factor in the tropics.

I feel the same way.

 

How is a "west-based" El Niño different from a "Modoki" (link) El Niño?  I've read a fair number of sites, and never been able to figure it out.

[The_Global_Warmer]

There is definitely very warm water surfacing between 120W and the SA coast.

 

Between DMI, unysis, and Noaa 2-3C+ anomalies have taken over Enso1-2

 

 

[jm1220]

Great thread guys, and very informative.

 

I wonder if by this time next year, the Southwest will go from record drought to record rainfall?

[JoMo]

Great thread guys, and very informative.

 

I wonder if by this time next year, the Southwest will go from record drought to record rainfall?

 

The CFS v2 definitely thinks so by this fall/winter.

[Quixotic1]

There is definitely very warm water surfacing between 120W and the SA coast.

 

Between DMI, unysis, and Noaa 2-3C+ anomalies have taken over Enso1-2

 

 

Is that a Benguela El Nino I spy?

[AvantHiatus]

Is that a Benguela El Nino I spy?

Atlantic El Nino?

[griteater]

How is a "west-based" El Niño different from a "Modoki" (link) El Niño?  I've read a fair number of sites, and never been able to figure it out.

 

West-based and Modoki Ninos are generally one and the same, with the max warm sea surface temperature anomalies centered just east of the dateline.  Based on the link you provided, it looks like a Modoki Nino has an additional distinction of having cool anomalies located in both the eastern and western Pacific, whereas any given west-based Nino may or may not have that exact anomaly pattern in the eastern and western Pacific.  

[StudentOfClimatology]

Atlantic El Nino?

IIRC the Atlantic ENSO has a period of like 5-7 months. I haven't read much on it in the literature so don't trust me there.

Since 2011 it has been quote volatile with it's oscillations.

[Quixotic1]

Atlantic El Nino?

Yeah if people are into it. Don't know much about it or its impact, however the SST anomalies off SA and West Africa kinda mirror each other right now.

[Ed Lizard]

West-based and Modoki Ninos are generally one and the same, with the max warm sea surface temperature anomalies centered just east of the dateline.  Based on the link you provided, it looks like a Modoki Nino has an additional distinction of having cool anomalies located in both the eastern and western Pacific, whereas any given west-based Nino may or may not have that exact anomaly pattern in the eastern and western Pacific.  

 

IIRC, the difference is huge for Atlantic Tropical Fans, the Central/West based doesn't kill the Atlantic tropics the way an East/Central based Nino does.

 

The at least as important question, will we have the kind of Nino that ends the California and Texas droughts next cool season?  Hoping experts will way in with cheerful news about next Fall/Winter.

[icebreaker5221]

IIRC, the difference is huge for Atlantic Tropical Fans, the Central/West based doesn't kill the Atlantic tropics the way an East/Central based Nino does.

 

The at least as important question, will we have the kind of Nino that ends the California and Texas droughts next cool season?  Hoping experts will way in with cheerful news about next Fall/Winter.

 

Generally, west-based Ninos do not strengthen the subtropical jet over the southern U.S. or the Caribbean as much as an east-based Nino.  This typically translates to lower wind shear and less of an impact on TCs, although numbers are still generally lower in west-based Ninos than most neutral or Nina seasons. 

 

For the second question, that depends both upon the strength of the El Nino as well as location.  Generally, the stronger the Nino and the more east-based it is, the greater the precipitation anomalies for CA and TX.  I think most would agree it's still too early at this time to determine peak strength and location.  Many El Ninos can be real drought busters.  1965-66 is an obvious counter example, which was a bad drought year for CA and about average for TX.  Note that it was a strong but not super El Nino and west based.  Odds are good for a wet winter, but far from guaranteed. 

 

SST anomalies Dec-Mar 1965-1966:

 

Precipitation anomalies Dec-Mar 1965-1966:

[JBG]

Generally, west-based Ninos do not strengthen the subtropical jet over the southern U.S. or the Caribbean as much as an east-based Nino.  This typically translates to lower wind shear and less of an impact on TCs, although numbers are still generally lower in west-based Ninos than most neutral or Nina seasons.

Then why do West-based Niños amp up East Coast snowfalls so much? Good examples are 1957-8, 1977-8, 1987-8 (not sure on that one) and the granddaddy of them all, 2009-10?

 

For the second question, that depends both upon the strength of the El Nino as well as location.  Generally, the stronger the Nino and the more east-based it is, the greater the precipitation anomalies for CA and TX.  I think most would agree it's still too early at this time to determine peak strength and location.  Many El Ninos can be real drought busters.  1965-66 is an obvious counter example, which was a bad drought year for CA and about average for TX.  Note that it was a strong but not super El Nino and west based.  Odds are good for a wet winter, but far from guaranteed.

Was 1972-3 (either East-based or basin-wide) or 2009-10 a drought-buster? I don't know answer on those.

[icebreaker5221]

Then why do West-based Niños amp up East Coast snowfalls so much? Good examples are 1957-8, 1977-8, 1987-8 (not sure on that one) and the granddaddy of them all, 2009-10?

 

All those years had well-timed stretches of highly -NAO and -AO.  When the moisture came, the cold air and blocking was in place.  Whether or not west-based Ninos actually favor blocking, it's hard to say, but history certainly appears that way.  If the El Nino is too strong, it will be moist but there is often a tendency to torch. 

 

Also, 09-10 was atypical.  The STJ was quite strong for a west-based Nino.

 

 

 Was 1972-3 (either East-based or basin-wide) or 2009-10 a drought-buster? I don't know answer on those.

 

72-73 was pretty wet for almost the entire southern U.S.  Not as wet as 82-83 or 97-98, but definitely above average for a very large area. 

 

09-10 was wetter for S CA through TX than your average west-based El Nino, and also quite wet along the east coast. 

 

09-10:

[ORH_wxman]

All those years had well-timed stretches of highly -NAO and -AO.  When the moisture came, the cold air and blocking was in place.  Whether or not west-based Ninos actually favor blocking, it's hard to say, but history certainly appears that way.  If the El Nino is too strong, it will be moist but there is often a tendency to torch. 

 

Also, 09-10 was atypical.  The STJ was quite strong for a west-based Nino.

 

 

 

72-73 was pretty wet for almost the entire southern U.S.  Not as wet as 82-83 or 97-98, but definitely above average for a very large area. 

 

09-10 was wetter for S CA through TX than your average west-based El Nino, and also quite wet along the east coast. 

 

09-10:

cd192_138_87_104_135_11_51_22_prcp.png

 

 

 

Yes, the biggest reason west based Ninos are better for east coast snows is it tends to have the N PAC low further W...more a true Aleutian Low which is better for cold air. The east based Ninos (which the really strong ones usually are) tend to put it more in the GOA and usually much larger....this tends to flood the CONUS with mild air.

 

There's obviously exceptions to the rule of course. It would be nice if we had a much larger database of the ENSO and their strength/orientation than we currently do.

[Dsnowx53]

The SOI has not dropped to negative, and has remained slightly positive. It seems that perhaps the early May rapid fall was due to the MJO being in phase 8 and phase 1, but now that the MJO has weakened, we're back near neutral again. We need to see the SOI drop independently of MJO at some point if we want a 1997-1998 El Nino. 

 

That being said, the westerly currents still look quite impressive for the most part, and despite the lack of true westerly wind bursts, there appears to be a pretty potent Kelvin Wave east of the Date Line. This could explain the backbuilding of the very warm subsurface anomaly. 

 

[Dsnowx53]

All those years had well-timed stretches of highly -NAO and -AO.  When the moisture came, the cold air and blocking was in place.  Whether or not west-based Ninos actually favor blocking, it's hard to say, but history certainly appears that way.  If the El Nino is too strong, it will be moist but there is often a tendency to torch. 

 

Also, 09-10 was atypical.  The STJ was quite strong for a west-based Nino.

 

 

 

72-73 was pretty wet for almost the entire southern U.S.  Not as wet as 82-83 or 97-98, but definitely above average for a very large area. 

 

09-10 was wetter for S CA through TX than your average west-based El Nino, and also quite wet along the east coast. 

 

09-10:

cd192_138_87_104_135_11_51_22_prcp.png

 

 

I think the fact that the 09-10 Nino was so strong, yet so westerly based was the more atypical facet of it, rather than the strong STJ. It was the strongest west-based Nino on record, so I think that accordingly, its STJ was much stronger than other west-based Ninos. 

[andyhb]

Also, 09-10 was atypical.  The STJ was quite strong for a west-based Nino.

 

Also need to remember how much the blocking was on roids that winter especially in February.