Triple-digit heat continues to scorch parts of the U.S.

A dangerous heat wave is baking much of the United States for yet another day, as states in the South and areas out West prepare for a scorching Fourth of July holiday.

A dangerous heat wave is baking much of the United States for yet another day, as states in the South and areas out West prepare for a scorching Fourth of July holiday.

High heat and humidity has blanketed the South for days after a heat dome that parked over Texas for three weeks expanded into neighboring regions. Meanwhile in the interior of California and parts of the Southwest, temperatures spiked over the weekend and triple-digit conditions are expected to persist through Tuesday, according to the National Weather Service.

The overlapping and unrelenting heat waves across the southern part of the country are the kinds of extreme heat events that climate scientists say will be more common in a warming world. Studies have shown that climate change is making heat waves more frequent, more intense and longer-lasting.

In an update Monday, the National Weather Service said heat across the South “will be less oppressive today,” but added that heat index values — the “feels like” temperatures when humidity and air temperatures are combined — could reach up to 110 degrees Fahrenheit. These conditions “can be dangerous if spending an extended amount of time outdoors,” the agency said.