Louisville, KY

Weather Forecast Office

El Nino and La Nina Information

Current Conditions

El Niño conditions are ongoing.
El Niño advisory currently in effect.
El Niño will gradually weaken during spring 2016.
One of the strongest El Niño's since reliable records began in 1950, with similar strength to 1982-83 and 1997-98.

Quick Facts

Moderate to strong El Niño/La Niña episodes pose a greater chance of affecting Kentucky weather compared to weak episodes.
Meaningful impacts for Kentucky are most common from mid winter through spring.

What is El Niño and La Niña?

El Niño: A warming of the ocean surface in the central and eastern tropical Pacific Ocean. Over Indonesia, rainfall tends to become reduced while rainfall increases over the open Pacific. The low-level surface winds, which normally blow from east to west along the equator (“easterly winds”), instead weaken or, in some cases, start blowing the other direction.
La Niña: A cooling of the ocean surface in the central and eastern tropical Pacific Ocean. Over Indonesia, rainfall tends to increase while rainfall decreases over the open Pacific. The normal easterly winds along the equator become even stronger.

Maps of sea surface temperature anomaly in the Pacific Ocean during a strong La Niña (top, December 1988) and a strong El Niño (bottom, December 1997). Maps by NOAA Climate.gov, based on data provided by NOAA View.

El Niño/La Niña is one of the most important climate phenomena on Earth due to its ability to change the global atmospheric circulation, which in turn influences temperature and precipitation across the globe. We also focus on El Niño/La Niña because we can often predict its arrival a few seasons in advance of its strongest impacts on weather and climate

How did El Niño get its name? Before La Niña was even recognized, South American fisherman noticed the warm-up of coastal waters that occurred every so often around Christmas. They referred to the warming as “El Niño,” (niño being Spanish for a boy child) in connection with the Christmas holiday. It wasn’t until the 1980s that the term La Niña gained prominence.

Typical late fall through early spring upper level jet stream positions associated with moderate to strong La Niña (left) and El Niño (right) events. During La Niña, a variable Pacific jet stream in association with a polar jet stream shifted further south favors below normal precipitation across the southern US, with below normal temperatures across the northern US. During El Niño, a strong and amplified Pacific jet stream extending across the southern US in association with a polar jet stream shifted further north into Canada favors above normal precipitation across the southern US, and above normal temperatures over the northern US. Based on original graphics from NOAA’s Climate Prediction Center.

Does El Niño/La Niña Impact Kentucky and Indiana Weather?

Affects from El Niño/La Niña tend to be weak across the Ohio and Tennessee Valleys. However, moderate and especially strong events do at times impact the region with varying weather conditions, especially during the late fall through early to mid spring months. The following graphics depict November through March temperature and precipitation anomalies associated with nine of the strongest El Niño and La Niña episodes. These composites DO NOT represent a forecast of expected conditions.

El Niño Nov-Mar Temperature Anomalies	El Niño Nov-Mar Precipitation Anomalies

These composites DO NOT represent a forecast of expected conditions. November through March temperature and precipitation anomalies determined from nine of the strongest El Niño episodes since 1950. Warm colors indicate above normal temperatures (left) and below normal precipitation (right), while cool colors indicate below normal temperatures (left) and above normal precipitation (right). Near normal temperatures are favored across much of Kentucky, with slightly above normal temperatures in Indiana. Below normal precipitation is favored. Images courtesy of NOAA's Earth System Research Laboratory.

La Niña Nov-Mar Temperature Anomalies	La Niña Nov-Mar Precipitation Anomalies

These composites DO NOT represent a forecast of expected conditions. November through March temperature and precipitation anomalies determined from eight of the strongest La Niña episodes since 1950. Warm colors indicate above normal temperatures (left) and below normal precipitation (right), while cool colors indicate below normal temperatures (left) and above normal precipitation (right). Slightly above normal temperatures and above normal precipitation are favored, especially in Kentucky. Images courtesy of NOAA's Earth System Research Laboratory.

Risk of Temperature/Precipitation Extremes

The below sixteen images depict the odds of extreme wet/dry or warm/cold fall-spring months associated with historical El Niño/La Niña episodes. Extreme weather is defined as being in the highest or lowest 20% of the 100 year record. The climatological average risk of extreme weather any given season is 20%. These composites DO NOT represent a forecast of expected conditions.

El Niño: Increased Risk of Temperature Extremes
November-January	December-February

January-March	February-April

These composites DO NOT represent a forecast of expected conditions. The above four images depict the odds of extreme warm or cold fall-spring months associated with past El Niños. Extreme weather is defined as being in the warmest or coldest 20% of the 100 year record. The climatological average risk of extreme weather any given season is 20%. Warm colors indicate an increased risk of warm temperature extremes, while cool colors indicate an increased risk of cold temperature extremes. There is no statistically significant increase in the chances of cold or warm extremes in Indiana and Kentucky in the winter and spring during El Niño. Click images to enlarge. Images courtesy of NOAA's Earth System Research Laboratory.

El Niño: Increased Risk of Precipitation Extremes
November-January	December-February

January-March	February-April

These composites DO NOT represent a forecast of expected conditions. The above four images depict the odds of extreme wet or dry fall-spring months associated with past El Niños. Extreme weather is defined as being in the wettest or driest 20% of the 100 year record. The climatological average risk of extreme weather any given season is 20%. Warm colors indicate an increased risk of dry precipitation extremes, while green colors indicate an increased risk of wet precipitation extremes. There is an increased risk of extremely dry weather in Indiana and Kentucky, especially during January through March. Click images to enlarge. Images courtesy of NOAA's Earth System Research Laboratory.

La Niña: Increased Risk of Temperature Extremes
November-January	December-February

January-March	February-April

These composites DO NOT represent a forecast of expected conditions. The above four images depict the odds of extreme warm or cold fall-spring months associated with past La Niñas. Extreme weather is defined as being in the warmest or coldest 20% of the 100 year record. The climatological average risk of extreme weather any given season is 20%. Warm colors indicate an increased risk of warm temperature extremes, while cool colors indicate an increased risk of cold temperature extremes. There is a slightly increased chance of warm temperature extremes in Kentucky, especially in November and January. Click images to enlarge. Images courtesy of NOAA's Earth System Research Laboratory.

La Niña: Increased Risk of Precipitation Extremes
November-January	December-February

January-March	February-April

These composites DO NOT represent a forecast of expected conditions. The above four images depict the odds of extreme wet or dry fall-spring months associated with past La Niña's. Extreme weather is defined as being in the wettest or driest 20% of the 100 year record. The climatological average risk of extreme weather any given season is 20%. Warm colors indicate an increased risk of dry precipitation extremes, while green colors indicate an increased risk of wet precipitation extremes. There is a slightly enhanced chance of wet extermes in the Ohio Valley, especially during January through March. Click images to enlarge. Images courtesy of NOAA's Earth System Research Laboratory.

Official Long Range Temperature and Precipitation Outlooks

Below are the latest official one and three-month temperatures and precipitation outlooks issued by the Climate Prediction Center.

One-Month Outlook
Temperature	Precipitation

Three-Month Outlook
Temperature	Precipitation

El Niño/La Niña & Spring Severe Thunderstorm Frequency

A paper published in Nature Geoscience in April 2015 by John Allen, Michael Tippett, and Adam Sobel examines the influence of El Niño/La Niña on springtime hailstorms and tornadoes across the contiguous United States from late winter through spring. The below images are adapted from the that paper, and show tornado and hail frequencies for the spring months (March-May) during El Niño (left column) and La Niña (right column). These composites DO NOT represent a forecast of expected conditions.

These composites DO NOT represent a forecast of expected conditions. Tornado and hail frequencies for the spring months (March-May) during El Niño (left column) and La Niña (right column). Purple favors higher storm event frequency, and brown favors lower storm event frequency. Specifics vary, but in general, springtime tornadoes and hailstorms are less frequent in the central and southern United States during El Niño, and more frequent during La Niña. Image courtesy of NOAA climate.gov.

Additional Links/Resources

Many thanks to Andy Kleinsasser of NWS Wichita for developing the template for this page