Tropical Pacific sea surface temperature anomalies
March 5, 2015

After a long watch, NOAA has issued an El Niño Advisory. What changed? And what does it mean for U.S. weather?

February 5, 2015

At the beginning of February, the atmosphere was looking a little bit like El Niño. Is this just another rolling stone?

Subsurface temperature anomaly
January 8, 2015

Sea surface temperatures were chugging along in late fall of 2014. What's going on now?

ENSO diagnostic flowchart
December 4, 2014

The ENSO Diagnostic Discussion just came out. Sea surface temperatures are solidly above average in the equatorial Pacific... so what's behind forecasters' decision not to declare El Niño conditions?

sea surface height anomaly from satellite data
November 6, 2014

What's behind the drop in probabilities this month? And why might forecasting this event be particularly tricky?

October 9, 2014

The forecast seems stuck on repeat. Why are we still calling for El Niño?

sea-surface height from satellite data
September 4, 2014

Forecasters are still calling for a 65% chance of El Nino conditions being met in the next few months. Isn't this late for the start of an ENSO event? 

CFSv2 ensemble forecast Nino3.4 sea-surface temperature
August 6, 2014

The chance of an El Nino has dropped to about 65%. What led to this change in the forecast?

July 10, 2014

Sea surface temperatures are up. So why haven't forecasters declared El Niño conditions? 

June 5, 2014

Chances that an El Niño will occur by summer are above 70%, hitting 80% by the fall. But subsurface temperature anomalies have tapered off some from earlier this spring, decreasing the odds the event will be as strong as the El Niño of 1997-98.