A strengthening El Niño could impact Horry County’s summer weather. Here’s how

The National Oceanic and Atmospheric Administration’s National Weather Service officially declared an El Niño has formed in the tropical Pacific on June 11.

El Niño, and its counterpart La Niña, is an oscillating climate pattern determined by the warm and cool phases of Pacific sea temperatures, which typically shift every two to seven years.

While a weak El Niño has already developed, there is a 63% chance it will become “very strong” during the fall or winter. But what does this mean, and how does it affect the region?

What is an El Niño?

An El Niño is not a weather event, but a climate pattern that occurs when sea temperatures are at least 0.5 degrees Celsius above normal temperatures in the equatorial Pacific for several consecutive months. The strengths vary between weak, moderate, strong and very strong — when sea temperatures are 2 degrees Celsius warmer than average.

El Niño is typically the strongest during the winter months, with global impacts highest in the Northern Hemisphere.

During an El Niño winter, the jet stream over the north Pacific shifts downward, amplifying storms across the southern region of the U.S. It also brings warmer temperatures across the northern region of the U.S. and drier condition in parts of the Midwest, according to NOAA.

NOAA scientists are predicting this El Niño could be one of the strongest to develop on record. The strength of an El Niño does not necessarily guarantee more severe weather, but the odds of severe weather developing increase.

What are regional impacts of the El Niño?

The biggest impact coastal South Carolinians may see from the El Niño is stronger vertical wind shear, which tends to suppress Atlantic hurricane formation. NOAA predicted a below-normal hurricane season, with eight to 14 named storms, three to six developing into hurricanes and one to three being major hurricanes (Category 3 or higher).

While there may be less hurricane activity, South Carolina could still see more rainfall and stormier weather. Higher chances of rain and snow can occur through the winter. The precipitation often moves in tangent with higher temperatures.

What are the seasonal outlooks for South Carolina?

According to the National Weather Service in Wilmington, North Carolina, impacts to temperatures and precipitation are not directly attributable to the El Niño, but the region may still see varying weather.

NOAA’s Climate Prediction Center’s temperature outlook predicts coastal South Carolina has a 40% to 50% chance of seeing above average temperatures through July. There’s also a 40% to 50% chance of above average precipitation for July 4-17.

The seasonal outlook predicts a 40% to 50% probability of above average temperatures and equal chances for below or above average precipitation from July to September.

Horry County has been battling a drought for several months. Even with chances of more rain, the drought is predicted to improve but still remain through September.