Weird CA weather linked to Arctic Oscillation, global warming
Forecaster extraordinaire Bill Patzert makes the connection, in a story in the Sac Bee:
This year, the blame [for the weird weather in California] falls on a complex interaction between La Niña and another phenomenon called a negative Arctic oscillation, Patzert and others said.
La Niña is marked by a cooling of equatorial waters in the Pacific – the opposite of El Niño. In the past, this pattern means an equal chance of wet or dry weather.
What made this year so wet was the negative Arctic oscillation.
Typical conditions make the Arctic colder than the mid-latitudes, which include the United States and Europe. This is a positive oscillation.
Negative conditions flip this around, making the Arctic warmer than usual and pushing cold air and a vigorous jet stream down into the United States and Europe.