Picture of snow falling in Lubbock on Tuesday, November 2, 2004.
Picture of snow falling in Lubbock on Tuesday, November 2, 2004.

What Does the Recent Development of El Niño Mean for the Weather this Winter?

El Niño conditions have recently developed across the Pacific and they are forecast to continue to strengthen into the fall and winter months (see the below graph). Since El Niño conditions do influence large scale weather patterns, you may wonder what that means for the upcoming weather this winter across the South Plains?

 

Model forecast of El Nino from August 2009. Click on the image for a larger view.

Forecasts of sea surface temperature (SST) anomalies for the Niño 3.4 region (5°N-5°S, 120°W-170°W). Figure courtesy of the International Research Institute (IRI) for Climate and Society. Updated 18 August 2009. The larger the values on the graph (positive and above 0.5), the stronger the El Niño episode. Click on the image for a larger view. 

Although exact conclusions are sketchy, as is the case with large-scale weather patterns and long range forecasts, there are some trends that can be noted across the South Plains that are correlated with El Niño. Below are some observations made from previous El Niño episodes as compiled by Lubbock Warning Coordination Meteorologist (WCM) Jody James. The information is broken down by the strength of the El Niño episode as defined in the table below. The Oceanic Niño Index (ONI) is defined as the 3 month running mean of sea surface temperature (SST) anomalies in the Niño 3.4 region (5oN-5oS, 120o-170oW).  


El Niño Definition 

Oceanic Niño Index (ONI)

Weak

0.5 - 0.9

Moderate

1.0 - 1.4

Strong

1.5 - 1.9

Extreme

2.0 +

The below information was compiled by examining precipitation information collected at the Lubbock airport. 


 Winter Precipitation (December through February)

Average Precipitation 1.88 inches normal
All El Niño Winters 2.28 inches 21% increase
Weak El Niño Winters 1.59 inches 15% decrease
Moderate El Niño Winters 1.59 inches 15% decrease
Strong El Niño Winters 2.52 inches 34% increase
Extreme El Niño Winters 3.88 inches 106% increase

Since 1950 there have been 17 El Niño episodes and 18 episodes during winter (One El Niño episode continued for two winter seasons, from 1986 through 1988). The above precipitation data is for climatological winter (December through February), while the snowfall data represents the cool season period from October through April. Extreme El Niño episodes occurred in 1972-73, 1982-83, and 1997-98. Since 1950, there have been 5 weak episodes, 4 moderate, 5 strong, and 3 extreme. 

 Winter Snowfall (October through April) 

Average Snowfall 10.4 inches normal
All El Niño Winters 13.9 inches 34% increase
Weak El Niño Winters 13.7 inches 32% increase
Moderate El Niño Winters 9.2 inches 12% decrease
Strong El Niño Winters 16.0 inches 54% increase
Extreme El Niño Winters 24.5 inches 136% increase


From the above tables we can see that:

  •  It appears that weak to moderate El Niño events may result in a decrease in total precipitation at Lubbock, but an increase in snowfall (greater percentage of snow).
  • There seems to be a strong signal for a significant increase in precipitation in strong to extreme episodes, both in overall precipitation and snowfall.
  •  In the extreme El Niño winters (there have only been 3), Lubbock's average snowfall is over 2 feet, which is more typical of the snowfall that you would expect to see in central Illinois or northern Kansas. Oddly though, in the 1997-98 extreme event, Lubbock's total winter precipitation was well above normal at 3.61 inches, but the snowfall was well below normal at 6.8 inches.

What does this all mean?

According to some of the computer models (graph toward the top), it appears that a moderate to strong El Niño episode is likely this upcoming winter. Hence, there may be a greater than average chance at the South Plains being wetter (and perhaps snowier) than normal this winter, particularly if a strong El Niño does develop. The official long range forecast for the United States reflects this, and can be found at the Climate Prediction Center by CLICKING HERE.

The development of El Niño is also sometimes linked with cooler than normal conditions across the southeast United State during the winter, but the correlation between temperatures and El Niño is relatively weak for the South Plains. The current long range forecast from the Climate Prediction Center for the South Plains calls for equal chances to a slightly greater than average chance of winter temperatures being above average.

Additional information:

To learn more about El Niño CLICK HERE.

To view common wintertime El Niño and La Niña influences across the entire United States CLICK HERE.


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