Understanding El Nino Weather

Mar 31, 2014 Homeowner Tips

Every year, the weather pattern, El Nino, affects climate patterns in regions around the world. The intersection of atmospheric and oceanic temperatures lead to changes in climate and weather patterns worldwide. One aspect of this change is the weather pattern, El Nino, occurring in two to seven year intervals. This weather pattern is characterized by an ongoing warming in the Pacific Ocean with higher sea surface temperatures, and can last 9 months to 5 years. The variation in length is usually classified as either ‘conditions’ or ‘episodes’ depending on whether the duration is longer or shorter than 9 months.

What Happens During El Nino?

The most obvious effects of El Nino are increased precipitation and thunderstorms. Because the phenomenon originates in the east and central Pacific, including parts along the western region of South America, the effects of El Nino are often stronger in South America than in North. Basically, the weather becomes warmer and wetter during an El Nino year, and along the equator and in the southern hemisphere, conditions can be extremely wet.

In the northern hemisphere, the winters during an El Nino year are typically warmer and drier than average. This results in less snowfall and somewhat above average temperatures for winter months. Some parts of the world tend to experience more rainfall and tropical storms while others experience dry conditions that can increase wildfire risks, worsen air quality, and harm agriculture.

El Nino and Climate Change

Some studies of historical weather data have shown that El Nino events have increased over La Nina, the cold weather phase, and may be linked to global warming. The last several decades have seen an overall increase in El Nino weather, but it may not be entirely clear if this is a direct contributor to increases in global atmospheric and ocean temperatures or a normal variation associated with the weather pattern. In any case, the El Nino weather pattern may in fact be a catalyst in global climate change, if not a direct contributor for its effect on global temperature, precipitation patterns, seasonal storms, and extreme weather conditions.

Don’t Forget About La Nina

The cold phase of El Nino is known as La Nina and is characterized by much of the same weather conditions as El Nino in many regions–wetter conditions in some places; drought conditions in others; and cooler air and stronger trade winds in across the Pacific. In North America, La Nina causes above average precipitation in the northern Midwest, Rockies, Pacific Northwest, and in Northern California, but average precipitation decreases in the southeastern and southwestern states. Typically, the further north, the more cold and snowfall during a La Nina year. In parts the southern hemisphere, droughts are common, while other regions experience heavier rains.

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