Frank Necci clears snow from St. Andrews Catholic Church, Friday, Dec. 29, 2017, in Erie, Pa. Tony Dejak AP
Frank Necci clears snow from St. Andrews Catholic Church, Friday, Dec. 29, 2017, in Erie, Pa. Tony Dejak AP

National

What's a 'bombogenesis' snowstorm, and why is the 'bomb cyclone' about to freeze you?

By Josh Magness

jmagness@mcclatchy.com

January 03, 2018 07:44 AM

So far, it’s been a frigid winter. Nine people across the U.S. have already died from cold weather this past week, according to Time, while cities like Chicago, Des Moines and Omaha have recorded near- or record lows.

Des Moines had a high of just -1 degrees, NBC reported, while the town of Erie, Pennsylvania, has seen nearly seven feet of snowfall since Christmas Eve.

And even Jackonsville, Florida, was colder than Anchorage, Alaska, on Tuesday, the AP reported.

Now cue the bomb cyclone, caused by a weather phenomenon known as a “bombogenesis.”

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According to the National Oceanic and Atmospheric Association, “bombogenesis” happens when the air pressure drops more than 24 millibars in 24 hours. Millibars are a way meteorologists measure atmospheric pressure, and such a steep drop like that — possibly caused by cold air over warm ocean waters — can trigger a bomb cyclone.

And this one could be big.

“Some computer models are projecting a minimum central air pressure of below 950 millibars at its peak, which would be nearly unheard of for this part of the world outside of a hurricane,” Andrew Freedman wrote for Mashable. “For comparison, Hurricane Sandy had a minimum central pressure of about 946 millibars when it made its left hook into New Jersey in 2012.”

Hearing the word "bombogenesis" and confused about it? Here's an explanation and how it relates to the upcoming East Coast storm. Stay tuned for forecast updates and read our key messages for this storm in our short range discussion: https://t.co/VNkruevXS6 pic.twitter.com/iwfR3CRcNd

— NWS WPC (@NWSWPC) January 3, 2018

Forecasters expect the temperature to dip into the low 40s and high 30s by Thursday as a cold front moves through South Florida. Edited by Matias J. OcnerMiami Herald Staff

So what could this ominously named weather phenomenon do?

For starters, it could keep us really cold. The bomb cyclone could trap the cold weather that is currently hitting the middle of the country when it heads for the East Coast, according to Time, basically putting much of the eastern part of the U.S. in a “deep freeze.”

You’ll also see a marked increase in rain, winds and snow. Plus, there might be lightning and a blizzard at the same time thanks to the bomb cyclone, which are in season from October to March, The Weather Channel wrote.

All day Thursday meteorologists are going to be glued to the new GOES-East satellite watching a truly amazing extratopical "bomb" cyclone off New England coast. It will be massive -- fill up entire Western Atlantic off U.S. East Coast. Pressure as low as Sandy & hurricane winds pic.twitter.com/6M4S3y75wT

— Ryan Maue | weather.us (@RyanMaue) January 2, 2018

This particular bomb cyclone is expected to start off the coast of Florida on Wednesday, then make its way up to New England the following day, Newsweek wrote. Along the way, the chilling storm is expected to bring snow and ice to Georgia, the Carolinas, the DC area and other states along its frigid path.

Some Key Impacts for wintry precipitation across SE GA and NE FL.



Down Power Lines, Widespread Electrical Outages, Snapped Trees or Branches, possible with Wintry Mix. Stranded Motorists, Disruption of Emergency Services are possible, with small amounts of ice and snow. . pic.twitter.com/k2fdwgktgA

— NWS Jacksonville (@NWSJacksonville) January 2, 2018

And here’s the bottom line for those dreading the cold: Temperatures are expected to dip to 20 to 40 degrees lower than normal, The Washington Post wrote, while wind speeds along the coast will be somewhere between 30 to 50 miles per hour.

Basically, expect a wintry hurricane.