Friday, August 14, 2015

Strengthening El Niño this upcoming winter

The idea of a strengthening El Niño into the 2015/2016 winter season has been recently making headlines, but the truth is El Niño actually started earlier this year.

New information released Thursday from NOAA suggests there is a 90 percent chance that El Niño will continue through the winter season, and an 80 percent chance that it could linger through Spring 2016.  Some also suggest that this El Niño could surpass the record El Niño event back in 1997/1998.  While this could be good news for folks of California who are in desperate need of rainfall, the '97/'98 El Niño also brought flooding rainfall to northern California.


What exactly is El Niño?  No, it's not Chris Farley from Saturday Night Live.  Rather, it's a periodic warming of the ocean waters in the Pacific Ocean near the equator that typically occur every 2-7 years.  Researchers still are not completely understanding as to why this occurs, but sometimes it can last up to 18 months.  On the opposite end, La Niña is the cooling of ocean waters in the Pacific Ocean near the equator.  For the Midwest, strong El Niño winters tend to suppress active winter severe weather.  While La Niña winters tend to increase wintertime severe weather across the Midwest.  During summer, moderate El Niño events also tend to suppress tropical systems in the Atlantic, while tropical systems in the Pacific flourish - likely due to warmer sea surface temperatures.

The effects of El Niño are most noticeable during the winter months in the United States, rather than during the summer months.  According to State Climatologist Jim Angel, El Niño winters tend to be warmer and drier, while fall tends to be slightly cooler and wetter than average.  With the possibility of a strong El Niño continuing into the winter season, one would tend to think that this winter might not be in favor for snow lovers.  The polar jet remains further north, not allowing arctic air to spill south as often.  The sub-tropical branch of the jet stream remains active along the southern part of the United States, typically bringing in wetter than normal conditions for the southwest and southeast.  While there have been some El Niño events that haven't followed this general trend, most have.  Time will tell what exactly will happen this fall and winter season, but if you're looking for an above average snowfall this winter, you may just have to wait another year.


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