What is El Niño and How Strong Is It?

El Niño occurs when sea surface temperatures (SSTs) in the central and eastern Pacific near the equator are warmer than normal.   During October, the SSTs increased nearly a degree with latest weekly average SSTs in the Niño-3.4 region at 1.5C above normal. 

Sea Surface Temperatures

There continues to be disagreement among the differerent computer models that forecast the strength of El Niño.   The majority do indicate that the three month average Niño-3.4 SST index will remain above 1.0°C through the winter which is considered at least moderate strength. You can find the latest El Niño Advisory and an El Niño FAQ Page on the Climate Prediction (CPC) website. 

How Will El Niño Effect The Winter in the U.S.?

The warmer than normal SSTs typically shift the patterns of the tropical rainfall that in turn changes the strength and location of the jet stream over the Pacific and consequently the continental U.S. This stronger jet stream over the southern U.S. brings increased storminess, more precipitation and cooler than normal temperatures from California to Florida. This pattern also prevents frequent cold air intrusions from Canada resulting in above normal temperatures over the northern U.S.  CPC indicates that El Niño will be the dominate factor that will affect the Winter Outlook for the U.S.  

How Have El Niños Effected Our Past Winters?

Utilizing climatological data dating back to 1950 of previous El Niño years, the trend is for St. Louis and Columbia winters to have near or above normal temperatures.  Records at St. Louis indicate that El Niño winters are drier and less snowy, but the statistics from Columbia show a more even spread.   Of course weather doesn't always follow climatology and there were two cold and snowy winters during El Niño in the late 1970s.

The following is data from previous El Niño years at St. Louis and Columbia, MO:

St. Louis - Lambert International Airport

Year

Mean Winter Temperature

Winter Precipitation

Winter Snowfall

Total Seasonal Snowfall

1971-2000 Normals

33.0°F

7.28"

17.1"

22.5"

1957-1958

32.5

5.38

12.8

25.1

1963-1964

 30.4

4.67

23.3 

31.5

1965-1966

 32.9

7.94

 9.7

 10.6

1968-1969

 32.2

 8.28

 9.4

 12.1

1969-1970

 30.0

 2.85

16.0

22.0

1972-1973

 32.5

 5.98

6.2

11.8

1976-1977

 26.1

 5.98

35.8

 36.3

1977-1978

 23.8

 5.64

43.9

 66.0

1982-1983

 37.3

 9.49

3.6

7.4

1986-1987

 35.4

4.44

24.2 

24.2

1987-1988

 32.6

13.03

15.4 

18.2

1991-1992

 39.6

5.11

 6.5

13.5

1994-1995

 36.3

7.24

 5.2

5.7

1997-1998

 38.0

 7.66

10.3

18.8

2002-2003

 32.3

4.98

29.5

29.8

2004-2005

 37.0

 12.62

10.9

12.8

2006-2007

 34.7

 7.13

10.5

13.2

# of seasons ABOVE normal

7

4

5

6

# of seasons  NEAR  normal

6

3

0

1

# of seasons BELOW normal

4

10

12

10

Columbia Regional Airport

Year

Mean Winter Temperature

Winter Precipitation

Winter Snowfall

Total Seasonal Snowfall

1971-2000 Normals

31.2°F

6.40"

18.2"

22.6"

1957-1958

31.4

6.30

18.0

27.0

1963-1964

30.4

2.99

22.0

27.1

1965-1966

33.4

4.74

13.9

14.7

1968-1969

31.0

8.31

12.7

18.1

1969-1970

28.6

1.89

12.8

19.9

1972-1973

30.0

7.46

14.3

25.2

1976-1977

24.6

3.26

32.6

35.0

1977-1978

24.3

3.47

31.9

54.8

1982-1983

36.5

7.69

3.1

4.0

1986-1987

34.7

4.99

21.2

21.2

1987-1988

30.6

9.28

28.0

33.0

1991-1992

37.4

5.20

6.2

13.6

1994-1995

33.0

7.48

25.1

27.3

1997-1998

36.3

7.51

7.6

14.0

2002-2003

30.1

4.36

17.3

18.2

2004-2005

35.5

8.86

6.9

12.1

2006-2007

32.5

6.09

24.1

27.7

# of seasons ABOVE normal

8

6

7

8

# of seasons  NEAR  normal

7

3

2

0

# of seasons BELOW normal

2

8

8

9

The latest local three month temperature outlook for St. Louis and Columbia that are downscaled from the CPC national outlooks indicate that there is equal chances for above, below, or near normal temperatures for December through February.  

St. Louis 
Columbia 

Additional local three month temperature outlooks and background information can be found in the climate section
of this website.

For additional information or questions about how this El Nino may impact eastern Missouri and southwest Illinois, contact:

Mark Britt
Senior Forecaster/Climate Program Leader
Email: mark.britt@noaa.gov


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