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Why the Stratosphere Gave a False ENSO Signal in the Spring


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This thread title is really outdated...maybe we need a new ENSO thread?

I fixed it; the thread title now applies. The first post is still relevant because it explains the false signal ENSO gave in the spring (from the stratosphere). I think a moderate La Nina is looking good, despite the hard stats since 1950.

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  • 4 weeks later...
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Just a quick update. ENSO 3.4 has been stable, but other regions have been slowly creeping colder. Moderate La Niña ONI peak looks the most probable ATTM, IMO

17AUG2011 	20.5-0.3 	24.5-0.5 	26.0-0.7 	28.2-0.2
24AUG2011 	20.2-0.5 	24.3-0.6 	26.1-0.6 	28.3-0.2
31AUG2011 	20.0-0.7 	24.4-0.5 	26.1-0.6 	28.3-0.2
07SEP2011 	19.7-0.9 	24.2-0.7 	26.1-0.6 	28.2-0.3
14SEP2011 	19.6-1.0 	24.1-0.7 	26.0-0.7 	28.0-0.5

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Just a quick update. ENSO 3.4 has been stable, but other regions have been slowly creeping colder. Moderate La Niña ONI peak looks the most probable ATTM, IMO

17AUG2011     20.5-0.3     24.5-0.5     26.0-0.7     28.2-0.2
24AUG2011     20.2-0.5     24.3-0.6     26.1-0.6     28.3-0.2
31AUG2011     20.0-0.7     24.4-0.5     26.1-0.6     28.3-0.2
07SEP2011     19.7-0.9     24.2-0.7     26.1-0.6     28.2-0.3
14SEP2011     19.6-1.0     24.1-0.7     26.0-0.7     28.0-0.5

wxmx,

I'm currently leaning to a WEAK three month averaged La Nina peak. I define weak as a three month long averaged peak anom. of -0.5 to -1.0 C in region 3.4. I'm basing this on comparisons to past La Nina weekly anomalies around this time of year as seen here.

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using the oni index for measuring enso it shows some interesting stats...any negative/ la nina year that went positive became an el nino...

1951

1957

1963

1965

1968

1972

1976

1986

1988

2002

2006

2009

1961 is the only weak negative that became weak positive and back to negative...-0.2 0.2 -0.6

Any negative that got to neutral 0.0 dropped back to negative the next year...

1960 -0.3 0.0 -0.2

1967 -0.6 0.0 -0.5

1996 -0.7 0.0 -0.4

2008 -1.4 0.0 -0.6

Other negatives/la nina's were multiple years...

2011 -1.3 0.0 ???

the last two three month periods oni index was 0.0...It looks like a downward trend has started...

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wxmx,

I'm currently leaning to a WEAK three month averaged La Nina peak. I define weak as a three month long averaged peak anom. of -0.5 to -1.0 C in region 3.4. I'm basing this on comparisons to past La Nina weekly anomalies around this time of year as seen here.

You could very well be right, and the statistical odds of having a La Niña of any strength are probably > 75% right now.

We have currently no public ECMWF ENSO forecast, but current observations were below all forecasted plumes in August (that month Euro's peak --or trough-- was borderline cold neutral/weak Niña).

OTOH, this month's Eurosip consensus is probably high-end weak to low-end moderate Niña

jt9gy.gif

And finally the CFS. The uncorrected version is the most aggressive, with a peak at strong Niña, while the PDF corrected and CFS v2 peak at moderate

KVTkY.gif

6Psl9.gif

DHi6w.gif

And, if we add some of the atmosphere signals that govern the ENSO state, which seem to favor a La Niña, like the very negative PDO, the negative QBO and the slow, but continued decline of the OHC, moderate beats weak by a nose.

Current odds, IMO

Moderate Niña 40%

Weak Niña 35%

Neutral cold 10%

Strong Niña 10%

Other 5%

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And, if we add some of the atmosphere signals that govern the ENSO state, which seem to favor a La Niña, like the very negative PDO, the negative QBO and the slow, but continued decline of the OHC, moderate beats weak by a nose.

Jorge, you know I agree with you about the La Niña and where we are heading but I am going to pick on you just because of the other thread. Why would a -QBO favor one ENSO state over another? Now, if you are suggesting the GLAAM relationship, fine...but there is also the convection relationship that others have been touting in my pinned thread. Why would a cooler than normal equatorial stratosphere favor a developing La Niña when it would serve to enhance convection? I guess all this proves is that the QBO, alone, doesn't really dictate ENSO given that everyone seems to have a different interpretation. Sam was arguing the opposite of you for why this La Niña won't get as strong (-QBO).

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Jorge, you know I agree with you about the La Niña and where we are heading but I am going to pick on you just because of the other thread. Why would a -QBO favor one ENSO state over another? Now, if you are suggesting the GLAAM relationship, fine...but there is also the convection relationship that others have been touting in my pinned thread. Why would a cooler than normal equatorial stratosphere favor a developing La Niña when it would serve to enhance convection? I guess all this proves is that the QBO, alone, doesn't really dictate ENSO given that everyone seems to have a different interpretation. Sam was arguing the opposite of you for why this La Niña won't get as strong (-QBO).

Good thing you picked on me HM... it made me 1) go and read and reread some interesting stuff about the QBO and ENSO, and 2) made me realize I was talking mostly out of my behind. If any, a -QBO would favor a warm event, though after the false spring signal, the deep +QBO (deep as in most of the stratosphere layers) was in fact probably favoring a Niña, this is not the case anymore, as the descending -QBO wave will promote -OLR anomalies along the equator...more convection which usually leads to warming, like you already stated.

This doesn't modify my thinking, as I think the machinery is already on the move (it might have a stronger effect for the 2012-2013 period, though), and other factors might overhelm the weak QBO signal.

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Good thing you picked on me HM... it made me 1) go and read and reread some interesting stuff about the QBO and ENSO, and 2) made me realize I was talking mostly out of my behind. If any, a -QBO would favor a warm event, though after the false spring signal, the deep +QBO (deep as in most of the stratosphere layers) was in fact probably favoring a Niña, this is not the case anymore, as the descending -QBO wave will promote -OLR anomalies along the equator...more convection which usually leads to warming, like you already stated.

This doesn't modify my thinking, as I think the machinery is already on the move (it might have a stronger effect for the 2012-2013 period, though), and other factors might overhelm the weak QBO signal.

You know I think you're awesome. It is interesting that for the first 17 days of September, it appears that the equatorial regions at both 30mb and especially 50mb remain westerly. The zonal wind anomalies at 30mb are the most surprising. But I guess this is why you can't just look at a number, especially when it is near zero. I am sure the September 30mb number will be negative, but these zonal wind anomalies right now sure don't look easterly to me yet. Throw in the active sun as of late and you have a breeding ground for a reinvigorating La Niña.

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  • 2 weeks later...

September QBO came in at -2.30. Definitely a slow descending easterly phase. Matches 1993 beautifully.

I don't know if your implying that 93-94 would be a good analog or not, but I came across this in Jan 1994.. which looks like a great winter around here..

JAN-94 FOR WILKES BARRE-SCRANTON, PA (948') LAT=41.3N LON= 75.7W TEMPERATURE PRECIPITATION ACTUAL NORMAL HI LO AVG HI LO AVG DEPT AMNT SNOW SNCVR HDD 1 40 20 30 34 20 27 +3 0.01 0.0 1 35 2 38 24 31 34 19 26 +5 0.00 0.0 0 34 3 30 21 26 33 19 26 +0 0.01 0.4 0 39 4 28 19 24 33 19 26 -2 0.62 9.1 10 41 5 28 13 21 33 19 26 -5 0.00 0.0 9 44 6 20 11 16 33 19 26 -10 0.02 0.4 8 49 7 24 18 21 33 19 26 -5 0.33 2.0 10 44 8 24 7 16 33 19 26 -10 0.16 3.9 12 49 9 20 6 13 33 19 26 -13 0.01 0.0 10 52 10 22 7 15 33 18 26 -11 0.00 0.0 9 50 11 28 10 19 33 18 26 -7 0.00 0.0 9 46 12 32 22 27 33 18 26 +1 0.18 3.5 11 38 13 36 30 33 33 18 26 +7 0.00 0.0 9 32 14 32 11 22 33 18 26 -4 0.06 0.4 9 43 15 12 0 6 33 18 26 -20 0.00 0.0 9 59 16 9 -4 3 33 18 26 -23 0.00 0.0 9 62 17 24 9 17 33 18 26 -9 1.05 15.0 26 48 18 23 -7 8 33 18 26 -18 0.01 0.0 26 57 19 -3 -13 -8 33 18 26 -34 0.00 0.0 25 73 20 11 -11 0 33 18 26 -26 0.00 0.0 24 65 21 13 -21 -4 33 18 26 -30 0.00 0.0 24 69 22 28 13 21 33 18 26 -5 0.00 0.0 23 44 23 30 7 19 33 18 26 -7 0.00 0.0 21 46 24 40 31 36 33 18 26 +10 0.00 0.0 16 29 25 37 26 32 33 18 26 +6 0.14 3.9 15 33 26 26 7 17 33 18 26 -9 0.17 3.5 19 48 27 30 4 17 34 19 26 -9 0.03 0.0 18 48 28 51 32 42 34 19 26 +16 0.49 0.0 13 23 29 40 29 35 34 19 26 +9 0.00 0.0 11 30 30 26 9 18 34 19 26 -8 0.00 0.0 11 47 31 24 2 13 34 19 26 -13 0.00 0.0 10 52 TOTALS FOR AVP HIGHEST TEMPERATURE 51 TOTAL PRECIP 3.29 LOWEST TEMPERATURE -21 TOTAL SNOWFALL 42.1 AVERAGE TEMPERATURE 18.6 NORMAL PRECIP 2.37 DEPARTURE FROM NORM -7.2 % OF NORMAL PRECIP 139 HEATING DEGREE DAYS 1429 NORMAL DEGREE DAYS 1208

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  • 5 weeks later...

Disagree. The start of the season could certainly be active, but I think we'll see an early end (very much in contrary to 2005), as QBO easterlies descend, imposing warm stratospheric temperature anomalies off the equator.

I'm sticking with the numbers I posted in February: 14/8/5, with 12 storms between June-September

Early end definitely verified. 1/1/0 in October. To what effect the QBO had is certainly debatable. I'm still waiting for final data on average tropopause heights across the tropical Atlantic.

Barring a late season surprise, which certainly can't be discounted, the season is at 17/6/3 ... probably closer to 15/6/3 in consideration of the rather liberal naming convention of the NHC early in the season. So I think my forecast did alright

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I don't know if your implying that 93-94 would be a good analog or not, but I came across this in Jan 1994.. which looks like a great winter around here..

JAN-94 FOR WILKES BARRE-SCRANTON, PA (948') LAT=41.3N LON= 75.7W TEMPERATURE PRECIPITATION ACTUAL NORMAL HI LO AVG HI LO AVG DEPT AMNT SNOW SNCVR HDD 1 40 20 30 34 20 27 +3 0.01 0.0 1 35 2 38 24 31 34 19 26 +5 0.00 0.0 0 34 3 30 21 26 33 19 26 +0 0.01 0.4 0 39 4 28 19 24 33 19 26 -2 0.62 9.1 10 41 5 28 13 21 33 19 26 -5 0.00 0.0 9 44 6 20 11 16 33 19 26 -10 0.02 0.4 8 49 7 24 18 21 33 19 26 -5 0.33 2.0 10 44 8 24 7 16 33 19 26 -10 0.16 3.9 12 49 9 20 6 13 33 19 26 -13 0.01 0.0 10 52 10 22 7 15 33 18 26 -11 0.00 0.0 9 50 11 28 10 19 33 18 26 -7 0.00 0.0 9 46 12 32 22 27 33 18 26 +1 0.18 3.5 11 38 13 36 30 33 33 18 26 +7 0.00 0.0 9 32 14 32 11 22 33 18 26 -4 0.06 0.4 9 43 15 12 0 6 33 18 26 -20 0.00 0.0 9 59 16 9 -4 3 33 18 26 -23 0.00 0.0 9 62 17 24 9 17 33 18 26 -9 1.05 15.0 26 48 18 23 -7 8 33 18 26 -18 0.01 0.0 26 57 19 -3 -13 -8 33 18 26 -34 0.00 0.0 25 73 20 11 -11 0 33 18 26 -26 0.00 0.0 24 65 21 13 -21 -4 33 18 26 -30 0.00 0.0 24 69 22 28 13 21 33 18 26 -5 0.00 0.0 23 44 23 30 7 19 33 18 26 -7 0.00 0.0 21 46 24 40 31 36 33 18 26 +10 0.00 0.0 16 29 25 37 26 32 33 18 26 +6 0.14 3.9 15 33 26 26 7 17 33 18 26 -9 0.17 3.5 19 48 27 30 4 17 34 19 26 -9 0.03 0.0 18 48 28 51 32 42 34 19 26 +16 0.49 0.0 13 23 29 40 29 35 34 19 26 +9 0.00 0.0 11 30 30 26 9 18 34 19 26 -8 0.00 0.0 11 47 31 24 2 13 34 19 26 -13 0.00 0.0 10 52 TOTALS FOR AVP HIGHEST TEMPERATURE 51 TOTAL PRECIP 3.29 LOWEST TEMPERATURE -21 TOTAL SNOWFALL 42.1 AVERAGE TEMPERATURE 18.6 NORMAL PRECIP 2.37 DEPARTURE FROM NORM -7.2 % OF NORMAL PRECIP 139 HEATING DEGREE DAYS 1429 NORMAL DEGREE DAYS 1208

IMO, if 93-94 is not a -PDO year...I don't think the analog will match.

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ASO oni index is -0.4...Other years with a similar index for ASO period...

2011...-0.4 and getting stronger...maybe a weak to moderate nina coming up...

2000...-0.4 got a little stronger...weak nina

1995...-0.5 got a little stronger...weak nina

1989...-0.3 remained steady and weakened...neutral

1985...-0.5 remained steady and weakened...neutral

1984...-0.3 got a little stronger...weak nina

1981...-0.3 remained steady and weakened...neutral

1978...-0.4 remained steady and weakened...neutral

1967...-0.4 got a little stronger...weak nina...

1962...-0.5 got a little stronger...weak nina...

1959...-0.4 remained steady and weakened...neutral

I doubt we see a neutral winter...It will probably be a weak or moderate nina...1967 has the same index for the last 4 tri monthly readings...

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Unc, I see you have 1978 on there. I've been curious as to how '78-79 stands as a winter analogue? It was a -PDO/-NAO winter. I don't know how the EPO or AMO was. It appears ENSO was neutral.

1978-79 was a neutral year but the Dec/Jan mei was .603...El Ninoish...oni was -0.1...The AO is kind of similar and tanked in December...February 1979 had one of the coldest periods on record with a snowstorm near the end of it...The end results of that winter Snowfall/Precipitation/Average temperature might end up similar in my area...It's not on my list of analogs...

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  • 3 weeks later...

Better get that high latitude blocking soon, the Pacific pattern won't hold long. Low level easterly winds have been ripping around the dateline, with the last 10 days average SOI a little over +20. We have been flirting with mod Niña weeklies for more than a month now, and will probably go below the -1.0C treshold for ENSO 3.4 soon.

u.anom.30.5S-5N.png

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Jorge, this is definitely a reason to give the ECMWF suite's MJO solutions credit here. This go-around of the MJO has a bigger battle with ENSO than last time. There is a wide area of strong -u winds at h85 and +u winds at h2. However, this wave is definitely very strong in the IO.

olr.last.3.gif

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Better get that high latitude blocking soon, the Pacific pattern won't hold long. Low level easterly winds have been ripping around the dateline, with the last 10 days average SOI a little over +20. We have been flirting with mod Niña weeklies for more than a month now, and will probably go below the -1.0C treshold for ENSO 3.4 soon.

It didn't take long...weeklies are down to -1.1 for ENSO 3.4. Strong low level easterlies did indeed stop the MJO wave on its heels, and they will continue unabated... bad news for winter weather lovers in most of the CONUS.

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