We are no longer seeing that arm of extremely above normal water temperatures from Japan through the Northern Pacific. Cool water anomalies are beginning to filter in to the region now, and this is posing problems for what used to be a very solid negative PDO.
Some of you may not know what the PDO is, so let's break it down. The PDO is the Pacific-Decadal Oscillation. It has two phases- positive and negative. The two phases are actually not what you think they are. A negative PDO consists of warm water anomalies stretched across the Northern Pacific, like what was seen on October 3. A positive PDO holds cool waters across the North Pacific, like we are currently seeing fill in.
The positive PDO generally brings cool conditions to the East, while the negative PDO is very warm for the same region. The Gulf Coast gets much of the precipitation during -PDO years, while +PDO years favor a dry East US in general. The +PDO is associated with El Ninos, and the -PDO with La Ninas.