El Nino is a phenomenon that occurs when sea surface temperatures are warmer than usual in the Pacific Ocean. The temperature change has a great impact on the ocean and global weather patterns.
On July 9, 2009, experts at the NOAA announced that an El Nino phenomenon had begun this year, and is expected to last through the winter of 2009-2010.
Why is it Called "El Nino"?
Because El Nino most typically arrives around early winter - or Christmastime - South American fisherman originally coined the term El Nino, which means "the little boy" in Spanish. It is a reference to the Christ Child, in honor of the Christian winter holiday.http://kids.earth.nasa.gov/archive/nino/intro.html
The phenomenon is also known as ENSO, which stands for El Nino-Southern Oscillation.
2009-2010 El Nino
Scientists at the NOAA announced that El Nino had arrived on July 9, 2009. It is expected to last through winter 2009-2010.
Although original predicted to be a mild El Nino, in September 2009, the NOAA updated its predictions to say that El Nino could become moderate to strong throughout the fall-winter 2009-2010. http://www.reuters.com/article/environmentNews/idUSTRE5893SG20090910
The last recorded El Nino event was in 2006. http://www.noaanews.noaa.gov/stories2009/20090709_elnino.html
2009 El Nino Threatens Flooding and Food Shortages in East Africa
The 2009 El Nino is a threatening menace to the people of East Africa who have been living under severe drought conditions. As the year draws to a close, El Nino weather patterns threaten to bring in heavy, driving rains that could cause flooding that will wipe away crops and kill livestock. If the El Nino forecast holds its course, millions of people in East Africa will go hungry and face a major food shortage crisis.
Major El Nino Events
1939-1940
1940-1941 (strong)
1941-1942 (strong)
1944-1945
1946-1947 (strong)
1951-1952 (strong)
1997-1998
1953-1954
1957-1958
1965-1966
1969-1970
1972-1973 (strong)
1976-1978 (strong 1977-1978)
1982-1983 (strong)
1987-1988 (strong)
1992-1993
1993-1995 (strong)
1997-1998 (strong)
2002-2003
2006-2007
2009-2010 (predicted)http://ggweather.com/enso/years.htm
2004-2005
The Typical Effects of El Nino
El Nino events bring both negative and positive changes to the world climate and weather system. Though effects can vary based on the intensity of the El Nino, these are typical effects of an El Nino:
- Higher winter precipitation to the Southwest United States
- More mild temperatures and less snowfall in the Northern United States
- Reduced hurricane activity in the Atlantic Ocean
- Higher frequency of winter storms in California
- Occasional flooding or mudslides in South and Central America
- Decreased rainfall and drought conditions in Indonesia
- Reduced food sources for marine life in the Pacific Ocean
- Weaker tradewinds
- Increased rainfall over the central tropical Pacific Ocean
http://www.noaanews.noaa.gov/stories2009/20090709_elnino.html
How El Nino Works
This diagram portrays the difference between normal climate conditions and El Nino climate conditions. Notice particularly how the trade winds are shifted and how cooler water off the western coast of the United States is warmed.
(image: http://www.ucar.edu/communications/quarterly/winter97/connection.html)
Map of How El Nino is Likely To Affect the United States Weather Patterns
Maps showing the potential effects of El Nino (above) and La Nina (below) on North America. (map courtesy of NOAA: www.noaa.gov)
2009-2010 Predicted El Nino Effects on the U.S.
As the El Nino event of 2009-2010 develops, scientists are developing a better idea of what the winter weather will be like in the United States.
East Coast Areas of the [[East Coast[[ of the U.S. should expect colder than normal temperatures, by as much as 5-10% on average. http://www.insuranceheadlines.com/Homeowners/6247.html
Upper Midwest A mild winter is likely in store for states in the upper midwest, where warmer-than-average temperatures are predicted due to El Nino effects. Precipitation will likely be below average. http://cloudyandcool.com/2009/09/23/nws-winter-2009-2010-winter-forecast/
Northwest Much like the upper midwest, the Pacific northwest will most likely see milder temperatures and less snowfall and precipitation than normal.http://www.cpc.ncep.noaa.gov/products/predictions/long_range/fxus05.html
South In areas including Texas, Florida, and other southern states, temperatures should be cooler than normal. Also expect more precipitation to hit the southhttp://cloudyandcool.com/2009/09/23/nws-winter-2009-2010-winter-forecast/
These long-range weather forecasts are considered typical predictions for El Nino years.
2009-2010 El Nino Threatens Drought in Australia
The El Nino event of 2009-2010 is likely to trigger an Indian Ocean Dipole situation, meaning that a high pressure ridge will be formed over northern parts of Australia that will block rainfall events from reaching the southeastern areas of Australia, causing rain shortages and even drought. The blocking pressure ridge is expected to hamper rainfall in southern Australia through the entire Australian summer.
This illustration demonstrates the movement of the dryer air toward Australia while the moist rainy fronts are drawn more toward the central Pacific Ocean.
References
Fast Facts
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"El Nino" term coined
1892
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"Southern Oscillation" term coined
1924
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Frequency
Every 3-8 years, on average
