By Joe D'Aleo
Monday, November 2, 2009
El Nino had diminished since its July peak.
Water cooled in the eastern Pacific.
But a new pool of warm water has built in the central Pacific as a westerly wind burst and a strong dip in the SOI pushed a Kelvin wave east along the thermocline and downwelled warmer water from near the surface.
The first surge in July occurred similarly and dissipated after coming east. See the latest animation here.
See the westerly wind burst below with warm anomaly central and cold east.
This will cause a spike in the ENSO in November into early December. In 2002, the El Nino peaked by December and then faded.
Given the fact that during the cold phase of the PDO, the El Ninos tend to be briefer and not as strong, I believe this will end earlier then most official forecasts indicate.
Also we should expect the PDO to spike temporarily as it does in most El Ninos during the cold PDO but then return negative, just as it dips to negative occasionally during La Ninas in the warm PDO mode.
The water temperatures from satellite used to measure the PDO are just surface water and can be influenced by local short term factors. The deeper water is the key and is better reflected in the dynamic height.
It suggests the negative PDO is still lurking underneath any surface warming. The Mantua (University of Washington) PDO turned slightly positive in September while the NCEP gridded version bounced but was still negative in the last report.