What Is a Bomb Cyclone? Why This Winter Storm Doesn’t Qualify

A not-quite-bomb cyclone brought dirty winter weather

TO Stephanie Pappas edited by Andrea Thompson

A winter storm that probably won't reach us.”bomb cycloneHowever, severe weather is expected across the eastern US today, with snow totals expected across parts of New York State and southern Maine.

This first significant burst of winter weather in the region comes thanks to a low-pressure system that has moved east over the past few days from the Midwest through the Ohio Valley and the mid-South, says Alan Gerard, a meteorologist and CEO of the company. Balanced weather. The disturbance leads to the formation of a second low pressure point off the mid-Atlantic coast. This other low is expected to strengthen as it moves north toward Cape Cod through today, but will likely remain “just outside bomb cyclone territory,” says Ashton Robinson Cook, a meteorologist with the National Oceanic and Atmospheric Administration's (NOAA) Weather Prediction Center.

A bomb cyclone occurs when a storm in the mid-latitudes drops sharply within 24 hours. The exact pressure drop depends on latitude: for example, at 40 degrees latitude (about the latitude of New York City), the pressure should drop about 18 millibars in 24 hours, according to NOAA. The cyclone moving north off the East Coast will continue to intensify impressively and bring strong winds and snow to parts of Maine, Cook said.

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However, this low pressure keeps warmer air close to the most populated areas from the northeast to the mid-Atlantic, Gerard says. “That's why Boston, through D.C., is getting mostly rain or some mixed precipitation,” he says. The heaviest snow, eight to 12 inches, is expected in southern New England and New York state.

Most of the precipitation will end by Wednesday morning, although blasts of cold air will continue to move into the central and eastern U.S. through next weekend, Cook said. According to Gerard, this cool situation may well continue throughout December.

While it's not always easy to relate polar patterns to North American weather, this winter storm was preceded by an episode of so-called stratospheric warming over the North Pole. This phenomenon occurs when the stratosphere—the layer of atmosphere above the troposphere where most of our weather occurs—suddenly rises several degrees. This warming has weakened polar vortexa circle of strong winds around the Arctic that keeps the coldest air around the pole. When it weakens, it can cause cold air to bleed south. A second polar vortex wobble could begin in the next couple of weeks, Gerard says.

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