Two Rare Overnight Heat Bursts Recorded In Colorado

By Chris Spears

DENVER (CBS4) - A relatively rare phenomenon was documented by two Colorado weather stations around midnight Thursday.

Its called a heat burst and it happened in both Akron and Yuma about an hour apart.

A heat burst occurs as a high-based thunderstorm, meaning the cloud base is several thousand feet off the ground, weakens and falls apart.

As that happens air that was inside the thunderstorm rushes out, almost like a big exhale.

If the air below the collapsing thunderstorm is extremely dry, any precipitation left inside the storm almost instantly evaporates, leaving a cold pocket of air briefly suspended in mid-air.

Because colder air is more dense that pocket rushes to the ground.

The sinking air undergoes a process called adiabatic warming as it descends through the very dry air, with the temperature increasing 10°C for every 1,000 meters of descent.

If this happens on top of a weather station the thermometer can record a rapid rise in temperature.

In Akron, the temperature at 10:30 pm was 68°F. It rose to 88°F by 11:45 pm and fell back to 70°F by 3 am.

In Yuma, the temperature was 64°F at 10:29pm, rose to 86°F by 12:49 am, and fell back to 63°F by 3:14 am.

Heat bursts are especially noticeable during the overnight hours.

Meteorologist Chris Spears travels weekly in the CBS4 Mobile Weather Lab reporting about Colorado's weather and climate. Check out his bio, connect with him on Facebook or follow him on Twitter @ChrisCBS4.