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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Blizzard of 2015 post-mortem media blitz

We had a huge snowstorm in the northeast US over the last couple of days. Here in New York City, it was not so huge as was forecast, leading to a lot of discussion in the media (social, traditional, and other) about what went wrong and right.

I have an op-ed in CNN summarizing my take on it. I don’t have a lot to add to that, except to say that if I could write it again there is one sentence I would change: “Being over-prepared, in contrast, merely leads to lots of griping on the Internet.” That’s a little too cavalier; there are real economic costs from all the transit shutdowns. I stand by everything else in the piece, including the overall message that those costs (which are not too huge according to the NY Times today) are a price worth paying for the benefits gained overall from forecasting and proactive emergency management.

I am quoted in stories in the Times, Mashable, and Climate Central saying similar things. Of the many many other interesting pieces on this event, Eric Holthaus’ piece in Slate gives a good inside view into how the Weather Channel arrived at a prediction of low snow numbers for NYC when the Weather Service was still going high, and Dennis Merserau’s piece in Gawker gives some good perspective.

While I think most thoughtful people understand that the proactive stance of the local & state governments was the right one overall, one specific question that seems legitimate is whether the subways really needed to close. They had never closed for snow before, and even in the moment it wasn’t obvious that it was necessary, even assuming the snow totals were going to be as high as forecast. This piece makes it seem as though it was Cuomo’s own – bad – decision, totally imposed by him on the MTA with no input from them, but the front page story in the NY Times today reports that the MTA head recommended it. This is one where I would like to understand the details bit better.