What the Heck is a Bomb Cyclone?

It sounds really cool, it’s actually kind of scary, and weather forecasters say it may or may not be headed your way. Maybe people are arguing about whether or not the winter storm in your area is or may become a bomb cyclone, or you’ve heard controversy over whether it’s a term we should us at all. It’s confusing, often sensationalized, and becoming all too easy to tune out.
But a name as ominous as bomb cyclones beseech clarification, how bad wills this storm be, exactly?
The phrase doesn’t refer to the storm itself. Instead, ‘bomb cyclone’ refers to a phenomenon expected to occur as this weather event unfolds. The official term is volatile cyclogenesis, or bombogenesis which—in addition to being my new favorite word—is actually really common.
The 'bombing' occurs when a low pressure system’s central pressure falls 24 millibars in 24 hours or less. Say what now?
Don't worry, we'll break it down. First off, what's a low pressure system? This is a region where the pressure of the atmosphere at sea level is lower than the surrounding area. As winds converge in the area, they rotate in the same direction as the Earth and can form a cyclone in the center of the region. The circulation within the system makes air move up higher into the atmosphere, where moisture in the air condenses and forms precipitation.
A millibar is simply a unit of measurement used by meteorologists to describe pressure—the force exerted by the air’s weight. The regular area pressure on Earth is 1013.2 millibars, and the lower the pressure drops within a cyclone, the more forceful a storm it creates. Severe hurricanes are often in the 900s, so what sounds like a little pressure drop can go a long way.
Drops in atmospheric pressure allow a storm system to pick up more air and strengthen, but a fall as sharp as 24 millibars in less than a day—while not exactly rare—is considered, in meteorological terms, explosive. This threshold came into common use after the publication of an article on the subject in 1980.

By – Abhishek Singh
Content - https://www.popsci.com/bomb-cyclone/