The Pacific-North American teleconnection pattern influences regional weather by affecting the strength and location of the East Asian jet stream, and subsequently, the weather it delivers to North America.

Over the span of days or weeks, the strength of surface air pressure over the North Atlantic seesaws between Iceland and the Azores Islands. The shifting pressure reflects changes in atmospheric circulation that have a big impact on mid-latitude weather in the U.S. and Europe. 

The Arctic Oscillation (AO) refers to an atmospheric circulation pattern over the mid-to-high latitudes of the Northern Hemisphere. The most obvious reflection of the phase of this oscillation is the north-to-south location of the storm-steering, mid-latitude jet stream.

ENSO model forecasts thumbnail

The model predictions during 2014 were not that shabby.  A major, strong El Niño was not well justified by the predictions. 

A first look at how we evaluate seasonal forecasts. How well do our eyes do?

An El Niño means lots of rain for California, correct? Well, some of the time, but not always.

How El Niño is like different flavors of ice cream.  Seriously.

June 2009 SST anomalies

As of late August 2014, tropical atmospheric temperatures appear to be responding more strongly to the ocean than they typically do at this early stage of El Niño development.   

Along with ENSO, what other climate patterns might be useful for predicting temperatures and precipitation in the United States?

OLR anomalies in 2012 versus 2014

Where is El Niño?  How is this year different from 2012 when El Niño was predicted, but never arrived?  

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