ENSO Blog

Our El Niño is still hanging around, and forecasters think it’s likely to stay through the summer. What happens after that is less clear, though, with about a 50% chance of El Niño continuing through the fall and winter. Things as they are The sea surface temperature across much of the tropical Pacific is still warmer than average, with the Niño3.4 Index coming in at 0.64°C above average during May (via ERSSTv5). The atmosphere also reflected weak El Niño during May, and both the Southern Oscillation Index the Equatorial Southern Oscillation Index were moderately negative. When these indexes are negative, it means the surface air pressure over the far western Pacific is higher t…   Read article

We’ve talked a lot about how ENSO impacts weather and climate around the world on this blog, but did you know that ENSO also could affect your health? In fact, ENSO can affect outbreaks of a variety of diseases, including cholera, Chikungunya, Zika, Rift Valley fever, and plague (yes, that infamous, Medieval-times kind of plague!). A multi-organization team of scientists (1) led by Dr. Assaf Anyamba of the Universities Space Research Association (USRA) at NASA Goddard Space Flight Center recently combined this disease knowledge with seasonal ENSO predictions to issue early warnings for possible disease outbreaks throughout the globe. These alerts proved to be quite accurate during the gre…   Read article

Forecasters estimate a 70% chance that our current El Niño will continue through the summer, and a 55-60% chance it will extend into the fall. Just a number El Niño conditions were still evident across the tropical Pacific Ocean during April, as the sea surface temperature in the Niño3.4 region averaged about 0.7°C warmer than the long-term average (via the ERSSTv5 database). Most computer models predict that the ocean surface will stay warmer than average in the Niño3.4 region, with the majority of predictions remaining above the El Niño threshold of 0.5°C through next fall. However, there is a broad range of potential outcomes shown here, and we’re still within the spring pred…   Read article

Some people like to sleep on their backs. Some people prefer to sleep on their stomachs or on their sides. Some people don’t sleep much at all! There are certain states we gravitate to when we sleep, often to maximize comfort. They are our preferred states. Would you be surprised if I were to tell you the atmospheric circulation operates in the same way, that certain patterns or flows appear more often than others because we’re not the only ones who like routine? One of these preferred states is the Pacific-North American Pattern, or as we scientists like to shorthand it:  The Almighty P-N-A! (Ok, we don't shout “Almighty!” every time… we whisper it.) I know the presence of…   Read article

The Great Puny El Niño of 2018­–19 continued through March, and forecasters predict it will likely remain through the summer and possibly continue into the fall. The tropical Pacific Ocean shows El Niño’s fingerprint clearly, with warmer-than-average sea surface temperatures stretching across the equator. Birds fly here The El Niño atmospheric response was also apparent in March, with continued greater-than-average cloudiness and rain near the International Date Line. This is the weakened Walker Circulation pattern, due to more rising air than average over the central Pacific as the warmth of the ocean is transferred to the air above. Both the regular-flavor Southern Oscillation In…   Read article