## Monday, June 14, 2010 ... //

### ENSO 3.4 reaches La Nina threshold

weekly report about El Nino and La Nina conditions (PDF, HTML),
the sea surface temperature anomaly in the Nino 3.4 region reached minus 0.5 °C (see page 5 of 30) which is the threshold defining a La Nina.

However, similar or colder average temperatures have to exist in the equatorial Pacific for five consecutive overlapping three-month periods for the La Nina-like conditions to be declared a La Nina episode.

Although models are split, I think it is more likely than not that the conditions will actually become a La Nina episode. Note that the last complete 3-month period (MAM 2010) was still safely in the El Nino range, +0.8 °C!

The expected cooling may help to keep the average 2010 temperatures below those of 1998.