A heat dome parks over the southern US Plains, Miami ties its hottest airport reading

A stubborn heat dome sat over the southern United States Plains through mid-August, pushing Texas and Oklahoma repeatedly past 100°F. Dallas came close to 107°F.

Separately, Miami tied its hottest-ever reading at its airport station, 100°F — a record that matters more for what it says about the baseline than for the single day.

What a heat dome actually is

A high-pressure system stalls over a region and acts as a lid. Air sinking under it compresses and warms, cloud cover is suppressed so the sun works uninterrupted, and each day starts hotter than the last because the night never fully clears the previous day’s heat. The pattern is self-reinforcing, which is why these events last for weeks rather than days.

The same blocking behaviour is what makes a monsoon depression stall over one district and dump a season’s rain in two days. The mechanism is a stuck weather pattern; the outcome depends on which pattern gets stuck.

Sources: WeatherBug, AccuWeather, NBC Miami.