First Alert Day: El Nino may be to blame for rains that will soak the Carolinas Thursday

First Alert Weather Forecast: 11pm

CHARLOTTE, NC (WBTV) - Anyone who pays the slightest attention to weather has certainly heard the term ‘El Nino’ in the past. Well, it’s looking like that cyclical weather pattern is on the way back again this winter. As a refresher, El Nino occurs when the eastern tropical Pacific Ocean just off the east coast of South America undergoes an unusual warming trend. So how on earth does ocean water around South America affect us? Keep in mind, the earth is 70% water, so not surprisingly the temperature of the oceans has a huge influence on the temperature of the atmosphere.

As the water warms, the heat it gives off hoists warm tropical air high into the atmosphere. This huge dome of warm air that expands across the equatorial region deflects the subtropical jet stream farther north, toward the United States. As this jet stream sets up across the southern half of the US, it acts as a highway to propel storm systems across the Gulf Coast States and the Southeast including the Carolinas.

As a result, we typically expect to see a higher-than-average number of storm systems to affect the Carolinas, and they typically have a large supply of moisture with their origin in the tropics.

Perhaps we’re already seeing evidence of this pattern as we recall the Weekend Winter Storm the previous weekend, then this past Friday’s soaker (ask any High School Football fan) and now the next one heading our way from - once again - Texas.

So if you hear experts tell you that El Nino winters around here tend to be wetter patterns, now you know why. They also tend to provide us cooler weather patterns, but not because of cold Arctic air penetrating the Carolinas (a recipe for snow) but rather, because frequent storms means less sunshine, we’ll simply see cooler weather, but not particularly cold weather.

If you’re not a fan of wet weather, the good news is, this should clear out in time for the weekend!

Meteorologist Eric Thomas

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