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IRI'S update concludes that this la Nina will be a weak one at best with a 60% of Neutral conditions developing by mid-2007.

Here's a part of there's discussion.

While many of the features in the tropical Pacific air-sea system are consistent with initiation of La Niña conditions -- shallow thermocline in the east, emergence of cold SST anomalies, and easterly wind anomalies -- considerable uncertainty remains over whether such conditions will lead to the growth of a La Niña event. For one thing, the ITCZ is closest to the equator at this time of the year, leading to weaker winds, and thus a weaker connection between subsurface and surface conditions. Still, the trend is currently toward cooling, and the cold/shallow subsurface anomalies necessary for further development of La Niña conditions exist. Thus there is a finite possibility that the system may reach La Niña conditions within the next several months. Probabilities initially favor ENSO-neutral conditions, but by mid-2007 the forecast suggests that weak La Niña conditions are more likely.

A re-emergence of El Niño conditions is very unlikely likely, with probabilities not exceeding 10% throughout the forecast period. <strong>There is an approximately 60% likelihood for ENSO-neutral conditions to start, with a 35% probability for La Niña conditions. By mid-2007, the probabilities for La Niña grow to 50%</strong>

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