ENSO Updates (2007 thru 2023)

[Ed Mahmoud]

I am so going to triumph in the numbers poll with my revision to 1997 type numbers.

[KWT]

Interesting to note that if anything the eastern zones have seen a slight drop in temps over the last 7-10 days or so and so overall most of the zones are still below 0C in terms of anomalies...I would be far less quick to claim we are heading towards El nino, esp given most of the basin is still close to la nina condtions, would only need a slight cooling again to tip it back into la nina numbers...

To get anything above say 0.5C+ by September will require quite a sharp rise compared to the average...yet alone to see a 1997 style el nino which isn't going to happen in time for the hurricane season...I'd stake anythng on that.

1997 may well have been claimed to be a neutral season by the forecasters but however the previous winter didn't have a borderline strong la Nina did it???

[cycloneye]

Interesting update from the Aussies about what is going on with the ENSO factor.

Compared with March, sea surface temperature data for April showed a further weakening of the La Niña pattern of cool anomalies, following the peak in around February. Though negative anomalies remain in the central to western Pacific, especially between 170°E and 140°W, these were weaker than the previous month and have shifted further to the west. Further east near the South American coast there was further weak warming, with an area of positive anomalies greater than 1°C evident at the monthly timescale. The central Pacific NINO indices, NINO3.4 and NINO4, both reflect the weakening of the La Niña signal with their monthly values rising to −0.8°C and −0.9°C respectively in April. At their peak in February they were −1.7°C and −1.5°C respectively. The NINO3 index is now only very weakly negative at the monthly time scale, being −0.1°C for the month.

http://www.bom.gov.au/climate/enso/

[cycloneye]

Compared with April, sea surface temperature data for May showed a further warming across the equatorial Pacific. Remnants of the La Niña pattern of cool anomalies persisted in the central to western Pacific, though these were much weaker than the previous month with only some small patches of anomalies below −1°C. Warm anomalies persisted near the South American coast, with an area of positive anomalies greater than +1°C remaining evident at the monthly timescale. The monthly NINO indices reflect this, with all indices showing further warming in May: the NINO3 index is now positive for the first time since February 2007. The NINO indices, NINO3, NINO3.4 and NINO4, have warmed by around 0.2 to 0.3°C and were +0.2°C, −0.5°C and −0.7°C respectively for May.

In terms of weekly data, all indices have shown further warming over the past two weeks, especially the NINO3 index, which has risen 0.5°C in the past two weeks to +0.5°C. The NINO3.4 and NINO4 indices are now on −0.3°C and −0.5°C respectively. When compared with two weeks ago, the 7-day SST anomaly map shows a strengthening and westward extension of positive anomalies in the eastern equatorial Pacific, with positive anomalies above +1°C now extending to around 120°W. Negative anomalies in the eastern to central Pacific have weakened further, with anomalies below −1°C now only present on the equator in a couple of small patches near the date-line. An animation of recent SST changes is available.

The La Niña signal in the sub-surface weakened further in May, with positive anomalies now present along the thermocline. Negative anomalies now only persist in the mixed layer near the date-line. A large area of positive anomalies remains in the western Pacific, though it has weakened since April. There has also been a continued decrease in the strength of the negative sub-surface anomalies in the central Pacific mixed layer, with all anomalies now above −1°C. A recent map for the 5 days ending 2nd June shows anomalies greater than +3°C remaining in the sub-surface in the western Pacific, though smaller in area than a fortnight ago, and anomalies greater than +3°C remaining in the sub-surface in the eastern Pacific. An animation of recent sub-surface changes is available.

An archive of past SST and sub-surface temperature charts is available.

The La Niña pattern of stronger-than-normal Trade Winds in the central and western Pacific broke down during May, with their strengths fluctuating around the long-term average during the past two weeks. A region of weakened Trade Winds not only remained across the central to eastern equatorial Pacific, but continued to expand towards the west. The latest weekly results shown in the TAO/TRITON map (small image above), for the five days ending 2nd June, are consistent with this, showing close to average Trade Winds in the western equatorial Pacific, and weakened Trade Winds elsewhere.

The May Southern Oscillation Index (SOI) was negative for the first time since mid-2007 (see SOI graph, SOI table). After an April value of +4.5 the SOI for May was −4.3. The 30-day SOI as of 2nd June was −4.0 (see graph above).

Cloudiness near the date-line in the central to western Pacific is another important indicator of warm/cool ENSO conditions, as it normally increases/decreases (negative OLR/positive OLR anomalies) during these episodes. Cloudiness around the equatorial date-line has mostly been below average since late May 2007, particularly so from December. It currently remains below average in keeping with the weak, negative SST anomalies in the region.

The latest survey (late May) of six international dynamic computer models, shows the majority predict neutral temperatures in the central to eastern Pacific continuing over the southern winter to early spring. However, two models do predict Pacific temperatures to rise a little over the El Niño threshold, with the remainder predicting conditions on the warm side of neutral. Of the five that predict beyond four months, all indicated the neutral conditions to continue through to the end of 2008. Recent forecasts from the POAMA model, run daily at the Bureau of Meteorology, predict neutral conditions to remain in the eastern to central Pacific through to January.

http://www.bom.gov.au/climate/enso/

They dont rule out a weak el nino at some point before 2008 ends.

[cycloneye]

http://www.cpc.ncep.noaa.gov/products/a ... ts-web.pdf

Climate Prediction Centers latest update does not indicate that a weak el nino may come during the ladder part of this year but as we say,never say never.

[cycloneye]

http://www.bom.gov.au/climate/enso/



The Aussies say in this latest update that Neutral ENSO will continue to dominate the equatorial Pacific thru the end of 2008.Click link for all the details of the update.

[KWT]

Yep so both agencies suggesting that we shouldn't see El nino, at least not before the hurricane season is done and dusted anyway.

[cycloneye]

http://www.bom.gov.au/climate/enso/soi.dt3



The Southern Occilation Index has been tanking into negative territory for the past month but now it has rised to above the zero line and now is positive meaning El Nino trying to appear in the pacific is not going to occur for the rest of 2008 as some latest analysis from the Aussies and Climate Prediction center haved said in their past updates for ENSO.

[hurricanetrack]

Date: 21 Jun, 2008

Average SOI for last 30 days : 2.60
Average SOI for last 90 days : 2.13
Daily contributor to SOI calculation: -24.25
---------------------------------------------

We'll see how long THAT lasts. With a big negative dive like that, if it persists, then a westerly wind burst could be on the way.

[cycloneye]

Anyone has the link to the data of the MJO (Madden Julian Occillation) as I lost it.

[srainhoutx]

Anyone has the link to the data of the MJO (Madden Julian Occillation) as I lost it.

Hope this helps

http://www.cpc.ncep.noaa.gov/products/p ... den-Julian Oscillation: Recent Evolution, Current Status and Predictions

[cycloneye]

Anyone has the link to the data of the MJO (Madden Julian Occillation) as I lost it.

Hope this helps

http://www.cpc.ncep.noaa.gov/products/p ... den-Julian Oscillation: Recent Evolution, Current Status and Predictions

Yes,thank you.

[srainhoutx]

No problem.

[hurricanetrack]

Not too long until that pulse moves east and in to the Western Hemisphere. From then on, we might see some development in July until the favorable conditions pass by.

[Jim Hughes]

Anyone has the link to the data of the MJO (Madden Julian Occillation) as I lost it.

Plenty of data here.

http://www.bom.gov.au/bmrc/clfor/cfstaf ... /index.htm

[Blown Away]

What is the range for neutral conditions?

[cycloneye]

Between +5 and -5.

[hurricanetrack]

Still tanking:

Date: 22 Jun, 2008

Average SOI for last 30 days : 1.74
Average SOI for last 90 days : 1.90
Daily contributor to SOI calculation: -27.06
---------------------------------------------


Anyone want to venture a guess as to why the SOI is dropping in such rapid fashion all of a sudden? Might that reason cause the Atlantic to come to life in about 2 weeks?

[cycloneye]

Many may not know what the Southern Occilation Index (SOI) is and what are the effects on El Nino,La Nina or Neutral ENSO being up or down so here is the whole explanation.

Southern Occilation Index Definition

[Windtalker1]

I found this info and thought it might be helpful in this discussion:


Negative PDO: 1900-1924, 1947-1976, 1999-??

La Niña
1904 1907 1909 1910 1911 1917 1918 1921 1923 1950 1951 1955 1956 1963 1965 1968 1971 1972 1974 1975 1976 1999 2000 2001

ENSO Neutral
1901 1902 1908 1913 1916 1922 1947 1948 1949 1953 1954 1957 1960 1961 1962 1967 2002

El Niño
1900 1903 1905 1906 1912 1914 1915 1919 1920 1924 1952 1958 1959 1964 1966 1969 1970 1973

Positive PDO: 1925-1946, 1977 - present

La Niña
1925 1932 1934 1938 1939 1943 1944 1945 1984 1985 1986 1989 1996

ENSO Neutral
1927 1928 1929 1933 1935 1936 1937 1946 1979 1981 1982 1990 1991 1993 1994 1997

El Niño
1926 1930 1931 1940 1941 1942 1977 1978 1980 1983 1987 1988 1992 1995 1998