ENSO Update: May of 2011 compares best to 2000.


The La Nina of last fall has been fading of late even though the ENSO index continues to be negative.  Since it is obvious that global temperatures are impacted by ENSO events (more on that here) I started trying to figure out what is going to happen for the coming fall when the Pacific Ocean will be determining the type of winter that North America and parts of Asia will be having later in the year.

My method was simple and didn’t use a single super computer or GCM, but I still trust the results.  The fall predication is based solely on how the current ocean anomaly pattern compares to past years.  I am not sure what methods are used by others for this, but after looking at enough anomaly maps for the oceans it is obvious that there is a cycle to the ENSO and is evident in the anomaly of the Pacific Ocean.

The Inconvenient Skeptic

Ocean Anomaly for the beginning of May 2011. Color is better if you click on it.

The pattern of a cooler region from California towards Indonesia and then back down to Chile is distinctive.  There is also a warmer than usual portion extending out from Central America into the Pacific.  This is the region of the ENSO and right now it looks like an El Nino might start developing, but that isn’t what the comparison says will happen.

The comparable week of 2000 is the best match for for the current anomaly patter in the Pacific.

Ocean Anomaly for the beginning of May 2000. Color is better if you click on it.

The cool region in the southern part of the Pacific is less well defined back in 2000, but the overall pattern is similar.  This is where the photo insert that the website uses is very handy as you can slide through the pictures and compare.  The North Atlantic is also cooler at the moment which also indicates that the AMO is weaker now than it was in 2000 as well.  Time will tell as the AMO is more of a general tendency than a hard and fast event like the ENSO.

There is also some correlation to early May of 2008.

The Inconvenient Skeptic

Ocean Anomaly for the beginning of May 2008. Color is better if you click on it.

All three years May’s were after a strong La Nina from the previous fall and ended up being weak La Nina years overall.  So based on the previous behavior of the Pacific Ocean it would appear that this fall will be a weak La Nina which tends to be neutral impact in the winter going into 2012.   So a more normal winter appears to be in the works for 2012.

The Invoncenient Skeptic

Record of the ENSO intensity.

Posted in Ocean: Sea Level and SST by inconvenientskeptic on May 4th, 2011 at 2:05 pm.

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