OK, La Niña Starting To Kick In

It's taking nearly-forever, but the Southern Oscillation Index (SOI) is poking over ten, finally.

A La Niña event is well established in the Pacific, with further intensification evident during the past three weeks. The main characteristics of the event are colder than average temperatures along the equator both on and below the surface, stronger than average Trade Winds and reduced cloudiness. The Southern Oscillation Index (SOI) is the one ENSO indicator that is yet to show a typical La Niña signal: it remains neutral at about +6 for the past 30 days. Computer models forecast the La Niña to last at least until the southern autumn of 2008.

Ocean temperatures immediately to the north and northwest of Australia (to near Sumatra) have been warming during October and November, although they remain somewhat cooler than would normally be observed during a La Niña. This would suggest an increased chance of a more typical La Niña rainfall pattern over Australia over the coming months.

And sure enough, it's raining a bit in Victoria....