Multiple outlets explain that a “heat dome” is a weather pattern that produces unusually high and often long-lasting temperatures. The concept refers to a dome of high atmospheric pressure that forms aloft, which suppresses vertical air movement. As a result, warm air is kept in place rather than rising and dispersing. With limited mixing of air, the surface remains intensely hot for extended periods. Some coverage also highlights that heat domes can increase discomfort by contributing to sticky, humid conditions alongside the elevated temperatures. The mechanism described generally involves large-scale atmospheric circulation that brings warm air into a region and then maintains it there, preventing cooler air from moving in effectively. Together, these processes can lead to heat waves that feel more extreme than typical hot spells because the warmth persists and is not relieved by normal airflow. The sources focus on defining how heat domes form and what they mean for day-to-day weather during hot summer periods.