It’s the bomb

A friend asks “So what is up with this bomb cyclone term? Is it just a blizzard with a more compelling name? Or is it something unique that I have not experienced before now? Is bomb cyclone a technical term?”

Answer: like “polar vortex”, “bomb” is a term that has been used by meteorologists for many years but is just now being brought into popular usage by weather media. It refers to a winter storm over the ocean that strengthens very rapidly – the technical requirement is that the minimum surface pressure drops by at least 24 hectopascals (hPa, also known as millibars, or mb) in 24 hours. The term was brought into the scientific literature by Fred Sanders and John Gyakum in a 1980 paper, here:

http://journals.ametsoc.org/…/1520-0493(1980)108%3C1589%3AS…

a less technical and more recent discussion is here:

https://www.fastcompany.com/…/is-bomb-cyclone-even-a-real-t…

a bit more history and some quotes from Gyakum:

https://www.huffingtonpost.com/…/bomb-cyclone-definition_us…

And if you want to know more about the polar vortex while you’re at it: Darryn Waugh, Lorenzo Polvani and I wrote an article about that term for the Bulletin of the American Meteorological Society that is a bit more scientific than what you’ll find in the mass (or social) media, but more accessible than a typical peer-reviewed research article:

http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-15-00212.1

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Polar vortex backlash in Salon

A couple days ago I had a light op-ed piece on “polar vortex backlash” (as far as I know, not the name of a band, yet) in salon.com. Here is the start of it:

Here in the U.S., the polar vortex is back, repeating its attack from last year. Like last year’s event, this one is extreme; it is bringing unusually cold temperatures and deluges of autumn snow. And it just turned serious, with at least 10 people killed by back-to-back city-burying blizzards in Buffalo. The forecast now threatens flooding as temperatures rise and rain falls on snow.

Here, however, is where some expert observers will beg caution: In most of the rest of the country, it’s just cold. And, in the bigger picture, the polar vortex is repeating what it has done every year since long before there were human beings on the planet. There has always been cold air over the pole in winter, and it has always moved around and sometimes moved over us.

Some weather stories take the normal behavior of the atmosphere and turn it into hype. That bothers many professional meteorologists in academia and the media. But I’m making my peace with it.

The full piece is here.