Forecasts Indicate a 65 Percent Chance of Weak Episode Developing

An El Niño event is coming.  Many have wondered when it is coming, but despite the delay, an ENSO episode is on the way.  Although forecasts from earlier this year calling for a strong one have diminished, there is still a very good chance of one occurring by the end of this year, or early next year.  According to NOAA’s El Niño portal, the National Weather Service suggests that there is still a 65 percent chance of an ENSO episode developing in the fall or the early winter.  Expectations of intensity have been reduced though to just a weak episode.

Right now, the ENSO alert status on the Climate Prediction Center web site is at El Niño Watch, which is “issued when conditions are favorable for the development of El Niño conditions within the next six months.”  The El Niño and Southern Oscillation is a global weather pattern shift that occurs when sea surface temperatures in the Eastern Pacific become higher than normal, and gradually migrate across the Pacific Ocean.  The effects of this weather shift is felt all around the globe.  Some of these effects may have positive or negative impacts depending upon where you live.

For example, an El Niño episode could result in increased rainfall in California, which would be a welcome sight.  Currently, California is experiencing one of its worst droughts in history.  So significant rainfall would be very beneficial.  However, with this year’s El Niño forecasted to be weak, there may be a limit to how much rain California would get.  ENSO also has an impact on the Indian Monsoon weather pattern, but it is a bit more complicated.  The Indian Monsoon is not rainfall, but a large scale weather pattern that affects the subcontinent.  It occurs between June and September, and is responsible for the majority of India’s yearly rainfall.  For the most part, El Niño generally suppresses monsoonal rainfall.

Other impacts across the United States includes drier conditions in the Ohio Valley, less than normal rainfall across Hawaii from late fall to early spring, and somewhat drier conditions in the Pacific Northwest and Northern Rockies.  Another key impact is on the tropics.  Warmer sea surface temperatures in the Pacific usually mean more activity in the Eastern, Central, and Western Pacific basins.  So far this year, there has been quite a bit of activity in the EPAC with 14 named storms, 8 hurricanes, and 5 major hurricanes including 3 Category Four storms and one Category Five system.  The Central Pacific has seen four storms in the area of Hawaii, and the Western Pacific has experienced a number of powerful typhoons.

Meanwhile, activity in the Tropical Atlantic has been lacking.  There have only been 5 tropical depressions, 4 named storms, 3 hurricanes, and no major hurricanes so far in 2014, and we are five days away from the statistical peak of the season.  However, the lack of activity in the Atlantic is not because of ENSO.  Instead, it is because of dry air over a vast portion of the Atlantic Basin.  Normally, when an El Niño occurs, it creates hostile upper level wind conditions in the Atlantic, which prevents tremendous thunderstorms from developing, which is a critical ingredient for tropical storm and hurricane formation.