"Nor'easter Bomb!" — Defusing the "Bomb" Hype

Since the media can't report on the weather without turning it into a hashtag or using a scare term to get people to click, many major weather events over the last few years were spun to sound a lot more disturbing than they really are. One of these includes the "bomb" that might happen near New England next week. It's not as rare or scary as you would think.

Articles posted today at the Washington Post, Syracuse.com, USA Today, and NJ.com — just to name a few — all reference this "bomb" that could happen off the New England coast next week.

Let's start with the basics: a nor'easter is a low pressure system that tracks along or near the coast of the northeastern United States, causing winds to blow out of the northeast (or "nor'easterly winds," hence its name) and often bringing intense snowfall to inland regions where the storm's ample moisture interacts with cold air.

"Nor'easter Bomb!" — Defusing the "Bomb" Hype

Low pressure systems strengthen due to a process called upper-level divergence. Divergence occurs when air essentially gets sucked out of one spot — or diverges — and moves to another spot. This occurs as a result of a jet streak, which is an area of intense winds within the high-altitude atmospheric river of air known as the jet stream.

When this divergence occurs, air from the surface rises to fill in the gap (nature abhors a vacuum), leaving less air at the lower-levels and thereby lowering air pressure, creating a low pressure center. Stronger jet streaks cause stronger divergence, which leads to deeper low pressure centers.

If a low pressure center gets caught in between two jet streaks (and two areas of divergence), the system can rapidly deepen, dropping dozens of millibars (standard unit of measure for air pressure) in one day. This rapid strengthening of a low pressure center is called bombogenesis, or that "meteorological bomb" everyone is talking about.

The technical definition of bombogenesis is when a low pressure center deepens by at least 24 millibars in 24 hours, which is pretty impressive.

"Nor'easter Bomb!" — Defusing the "Bomb" Hype

If the latest run of the GFS model is any indication, it looks like the potential nor'easter next week is going to take bombogenesis to the extreme. In the above surface pressure analysis for next Wednesday evening, the GFS wants to deepen the low pressure system to nearly 960 millibars — down from around 1000 millibars 24 hours earlier. That's a nearly 40 millibar drop in 24 hours. Kaboom.

Bombogenesis — that "bomb" — is nothing new. It just indicates that the low pressure system is expected to rapidly strengthen as it skirts by the New England coast. Depending on the track the storm takes, it could have a big impact on heavily populated areas towards the beginning of next week. Keep an eye on it this weekend.

[Images: this YouTube video / TwisterData (with drawn-on analysis by the author) / TwisterData]

[Late edit: Changed "de-hyping" to "defusing" in the title because I would hate myself forever if I passed up the opportunity to make that pun.]