>The August 2010 SST data through the NOAA NOMADS website won’t be official for at least another week. Refer to the schedule on the NOAA Optimum Interpolation Sea Surface Temperature Analysis Frequently Asked Questions webpage. The following are the preliminary Global and NINO3.4 SST anomalies for August 2010 presented by the NOMADS website. I’ve also included the weekly data through August 25, 2010, but I’ve shortened the span of the weekly data, starting it in January 2004, so that the wiggles are visible.
Also included at the end of the post are a comparison of the evolution of the 2010/11 La Niña to past La Niña events and a comparison of 1998 and 2010 global SST anomalies.
PRELIMINARY MONTHLY DATA
Based on the preliminary data, monthly NINO3.4 SST anomalies are continuing to drop, and the drop has them well into La Niña territory.
http://i38.tinypic.com/fx9ov8.jpg
Monthly NINO3.4 SST Anomalies
Monthly Global SST anomalies, according to the preliminary data, are stalled, changing only -0.01 deg C this month. This can happen after El Niño events. Refer to the comparison of 1998 and 2010 Global SST anomalies that follows.
http://i37.tinypic.com/jaamvp.jpg
Monthly Global SST Anomalies
WEEKLY DATA
The weekly NINO3.4 SST anomaly data have dropped significantly over the past week. They are now below -1.5 deg C.
http://i37.tinypic.com/x3iscm.jpg
Weekly NINO3.4 SST Anomalies
Weekly Global SST Anomalies are still flat. There are some minor wiggles, but the Global SST anomalies are still lagging the drop in NINO3.4 SST anomalies.
http://i34.tinypic.com/2eead1z.jpg
Weekly Global SST Anomalies
COMPARISON OF LA NIÑA EVOLUTIONS
As of the week centered on August 25, 2010, the 2010 NINO3.4 SST anomalies have not yet dropped below the low levels of the 1988/89 La Niña.
http://i38.tinypic.com/2u6lmv8.jpg
La Niña Evolution Comparison
COMPARISON OF 2010 GLOBAL SST ANOMALIES TO 1998
The following comparison graph shows that 2010 SST anomalies are not above 1998 levels. The weekly global SST anomalies are noisy, so I’ve also shown them smoothed with a 5-week running-average filter.
http://i34.tinypic.com/xddqiv.jpg
1998 And 2010 Global SST Anomaly Comparison
SOURCES
SST anomaly data is available through the NOAA NOMADS website:
http://nomad1.ncep.noaa.gov/cgi-bin/pdisp_sst.sh
or:
http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_sst.sh?lite=
Bob Tisdale - Climate Observations 
>Hi Bob -Thanks so much for the update. Definitely interesting to see the lag in global SST temperatures. Any thoughts on how much of the lag is due to the length of time it takes for the Atlantic to cool in response to the dropping tropical pacific?
>John: I recall a paper that said it took until the next winter for the Arctic to respond fully to an El Nino. It would take me a while to find it again, unfortunately. There are also the seasonal variations between hemispheres taking place. The hemispheres also have double peaks in response to an El Nino. It's really noticeable in 1997/98 in the Northern Hemisphere:http://i36.tinypic.com/102p3s1.jpgLots of lagged processes going on.
>Bob, back in May at Climate Audit there was a comment by Steve McIntyre that he thought that NMAT (night marine air temperature) data had some adjustments back in the 1940s.Have you found anything like that?DB
>DB: Sorry, I don't recall anything and I don't believe I have a comparison graph handy of the ICOADS "raw" version versus the Hadley Centre MOHMAT.
>Interesting, that in the contrary to global SST stalling, the satellite SST channel shows very steep and continuing drop, which started in April.
>Jurinko: The Reynolds OI.v2 SST data used in this post is satellite based also. Different satellite technology. And I assume you're talking about Dr. Spencer's posts. Keep in mind that he only includes the latitudes of 60S-60N, while these global datasets go pole to pole. I'll try to remember to include a graph of 60S-60N in my next update.
>Bob what is the lag time between the Nino SST drop and global SST drop? When can we expect the same large drop off in global SST as seen around week 35 of the 1998 data. Will the drop be similar?
>Bob, the Foltz and McPhaden paper had dust data for the Atlantic back to 1980. A new paper by Evan and Mukhopadhyay goes back to 1955:African dust over the northern tropical Atlantic: 1955–2008http://trane.evsc.virginia.edu/Publications_files/2010_Evan_Mukhopadhyay.pdfDB
>HR: I've never attempted to lag the trailing curves of NINO3.4 and global SST anomalies during the transition from an El Nino to a La Nina, so I can't answer your questions. Give me a week or so. I've got two other posts I'm trying to finish, but I'm also interested in seeing that lag. I have a feeling it's going to vary per ENSO event but we shall see.Regards
>DB: Thanks for the link to Evan and Mukhopadhyay
>I guess I'm interested in the lagged response as well.I note that the AMO region is at its highest level in the record right now (36 weeks after the peak of the Nino 3.4) but it didn't start declining until 39 weeks after the 1997-98 El Nino peak and has taken up to a year in other El Ninos (but it has also been less than 39 weeks). I couldn't find a solid tangible correlation before so dismissed it but obviously that was a mistake.