USA ENSO (El Niño/La Niña) & US Extremes Quiz
How ENSO shifts US precipitation, storms, winter patterns (10 questions).
USA ENSO (El Niño/La Niña) & US Extremes Quiz: Quick Study Notes
The El Niño-Southern Oscillation (ENSO) is a recurring climate pattern involving changes in the temperature of waters in the central and eastern tropical Pacific Ocean. These shifts, categorized as El Niño (warmer waters) or La Niña (cooler waters), profoundly influence global weather, including significant impacts on precipitation, storm tracks, and winter patterns across the United States. Understanding these variations is crucial for predicting seasonal outlooks and preparing for potential extreme weather events.
Key ENSO Impacts on the US
Key Takeaways
- El Niño warms Pacific waters, shifting the jet stream south over the US.
- La Niña cools Pacific waters, often pushing the jet stream north.
- El Niño generally means a wetter, cooler winter for the Southern US and drier, warmer conditions for the Pacific Northwest.
- La Niña typically brings a wetter, colder winter to the Northern US and drier, warmer conditions to the Southern US.
- Atlantic hurricane season tends to be more active during La Niña due to reduced wind shear.
- ENSO phases influence storm tracks, tornado activity, and drought patterns nationwide.
- These climate patterns are a major factor in seasonal weather forecasting for the United States.
Frequently Asked Questions about ENSO & US Weather
What is El Niño?
El Niño is the warming phase of the El Niño-Southern Oscillation (ENSO) cycle, characterized by unusually warm ocean temperatures in the equatorial Pacific Ocean. This warming impacts global atmospheric circulation, influencing weather patterns worldwide.
How does El Niño affect US winters?
During an El Niño winter, the southern tier of the United States typically experiences wetter and cooler conditions, with an increased risk of winter storms. Conversely, the Pacific Northwest tends to be warmer and drier than average.
What is La Niña?
La Niña is the cooling phase of the ENSO cycle, characterized by unusually cold ocean temperatures in the equatorial Pacific. This cooling similarly alters atmospheric circulation, leading to distinct weather impacts across the globe.
What are the common impacts of La Niña on the US?
A La Niña winter often brings colder and wetter conditions to the northern United States (especially the Pacific Northwest and Northern Plains) and warmer, drier conditions to the southern US. It is also associated with a more active Atlantic hurricane season.
Does ENSO influence extreme weather like tornadoes or droughts?
Yes, ENSO significantly influences extreme weather. El Niño can shift tornado activity eastward into the Southeast, while La Niña is often linked to enhanced drought conditions in the southwestern US and a more active Atlantic hurricane season due to changes in wind shear.

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