Heat dome to blast SC Lowcountry with 100+ degree heat July 4th weekend. Here’s what to expect

Extreme heat baked the Lowcountry over the weekend and forecasts warn it may return Fourth of July weekend.

The National Weather Service issued a heat advisory for the Lowcountry Sunday and Monday as forecasts predicted heat index values in the triple digits. Heat index values that high mean heat-related illness is likely with long exposure.

A combination of upper 90-degree Fahrenheit temperatures and moderate humidity created the extreme heat. The Lowcountry and much of the Southeast is under a pattern of stagnant air called a heat dome. Weather observations at Beaufort’s Marine Corps Air Station recorded a heat index of 107 Sunday Afternoon, and it fell to only 82 overnight.

And the Lowcountry may not see cooler temperatures for the foreseeable future. The Climate Prediction Center gives the Lowcountry a 50 to 60% chance of above-normal temperatures for the next three to four weeks.

What’s the forecast for the Fourth of July?

The Lowcountry remains under a major or moderate heat risk through the Fourth of July holiday weekend, according to the NWS. It forecasts temperatures in the low 90s through Friday, before temperatures climb starting on the Fourth of July. And little to no rain is forecast throughout the week.

The NWS is considering a heat advisory for the holiday weekend. Heat indices could reach 105 to 110 degrees on Saturday and Sunday due to near 100 degree temperatures and high humidity. Beach temperatures will be in the 90s as well.

The NWS forecasts high temperatures on the Fourth of July of 93 degrees on Hilton Head Island, 95 in Beaufort and Port Royal and 94 in Bluffton as of Monday. The forecast may change.

Forecast beyond the Fourth of July

The CPC forecasts above-normal temperatures to continue in the Lowcountry well into July. It forecasts a 50 to 60% chance through the next three to four weeks. The CPC also gives the Lowcountry a 33 to 40% chance of above-normal precipitation through the next three to four weeks. Increased precipitation may provide relief from the heat.

The NWS advises a moderate risk–a 40 to 60% chance–of extreme heat on Monday, July 6. It warns of triple-digit heat indices and minimal overnight cooling.

An El Niño formed over the Pacific Ocean in June, and according to the National Oceanic Atmospheric Administration, it will affect our weather. The El Niño will have little effect in July, according to the CPC.