Heat burst

From Glossary of Meteorology

heat burst

(Also heat thunderstorm.) Localized, sudden increase in surface temperature associated with a thunderstorm, shower, or mesoscale convective system, often accompanied by extreme drying.

The temperature jump can be so extreme that it is at times referred to as a "hot blast of air." Occurs in association with precipitation-driven downdrafts penetrating a shallow surface stable layer and reaching the ground.