“This storm developing off the Southeast coast will meet the meteorological criteria of a “bomb” as it rapidly intensifies. The signal for a storm has been evident since last week, but as the track has been fine-tuned, impacts to the I-95 corridor are now expected. Snow, strong winds, and very cold temperatures are expected particularly the further east one heads,” said Ed Vallee, meteorologist at Vallee Weather Consulting LLC.
Winter Storm Grayson, a very large and powerful winter storm is threatening the East Coast of the United States with heavy snow, intense winds, and record-setting low temperatures. Winter storm watches and warnings have been issued for many coastal regions in north Florida to Maine from Wednesday into late Thursday.
This week’s storm may end up being worse than your average nor’easter, according to Bloomberg. It could produce a “bomb cyclone,” otherwise known as a bombogenesis, a phenomenon that occurs when a system’s central pressure drops steeply – 24 millibars or more – in 24 hours. If current computer models hold, that’ll start to happen somewhere off Cape Hatteras, North Carolina, and continue as the storm moves north. Hurricane-force wind warnings have been posted off the coast where ships could encounter winds of 80 miles (130 kilometers) an hour and waves as high as 26 feet on Thursday.
“The real apex, the peak of the storm, will be Cape Cod to Nova Scotia,” said Gregg Gallina, a forecaster at the U.S. Weather Prediction Center in College Park, Maryland.
This particular storm, which is currently developing off the coast of Florida, will devour enough warm water that it could be considered a winter hurricane by the time it leaves the Mid-Atlantic coast late Wednesday.
The Weather Channel describes how a bombogenesis forms:
To be classified as a weather bomb, or having undergone bombogenesis or “bombing-out”, the central pressure of a low pressure system must drop at least 24 millibars within 24 hours.
Bombogenesis results when there is a large temperature gradient, usually between a cold continental air mass and warm sea-surface temperatures. However, it can also be the product of a cold polar air mass and much warmer air from the south, say, over the Plains states.
Over that temperature contrast, a powerful, intensifying jet-stream disturbance triggers air to rise and kicking off the bombogenesis process.
Frequently, Nor’easters are weather bombs due to cold air surging southward from Canada combined with the warm ocean waters of the Gulf Stream.
“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,” said Mashable’s Andrew Freedman. “For comparison, Hurricane Sandy had a minimum central pressure of about 946 millibars when it made its left hook into New Jersey in 2012.” By Thursday, the European model forecasts the storm to register at 946 millibars off the coast of Long Island, making it a rather intense storm on par with destructive hurricanes.