NEW YORK (WABC) -- A summer heat wave is once gain upon us, with temperatures soaring into the 90s and real-feels in the triple digits. But what is a heat wave? What defines one, and how does it form?

Heat waves can form when a high-pressure system moves into a region and stalls. The system can force warm air downward, acting like a cap as it keeps the cool air near the surface from rising, ...

Gravity wave clouds form in wave-like patterns in sky, oftentimes resembling ripples in a body of water from a rock being thrown. These types of clouds are created from air in the atmosphere coming ...