El Niño / La Niña Effect on U.S. Weather
What Effect Does El Niño/La Niña Have On Our Weather?
In general, winter El Niño episodes (top map) feature a strong jet stream and storm track across the southern part of the United States, and less storminess and milder-than-average conditions across the North. La Niña episodes (bottom map) feature a very wave-like jet stream flow over the United States and Canada, with colder and stormier than average conditions across the North, and warmer and less stormy conditions across the South.
This information can be verified by looking at the Composite Temperature and Precipitation Anomaly maps for the top ten El Niño and La Niña events displayed below.
El Niño Events
La Niña Events