A powerful late-winter storm combining rivers of moisture and frigid temperatures – a phenomenon known to some as a “bomb cyclone” – was expected to dump snow from the US deep south all the way to the Canadian border over the weekend, forecasters said.
With forecast snowfall ranging from about 4in in northern Alabama and Mississippi to about 13in in northern Maine, the storm could cause travel problems and power outages across much of the eastern US.
The National Weather Service said 7in to 12in of snow could be expected in northern Pennsylvania and New York with winds gusting as high as 45mph.
Philadelphia residents, while expecting only a few inches of snow, were warned that blizzard-like conditions were possible and later a flash freeze was possible.
Gale warnings were in effect in coastal New Jersey and Delaware, with gusts of 40mph to 50mph possible and forecasters warning of tree damage and power outages as well as rough boating conditions. A wind advisory was in effect for other areas.
On Saturday morning, a swathe of territory from eastern Tennessee to the mid-Atlantic and north-east saw heavy snow. In West Virginia, St Albans saw 9in. Knoxville, in Tennessee, Pittsburgh, in Pennsylvania and Buffalo in New York had seen 6in to 7in, the Weather Channel said.
“With this bomb cyclone, maybe what’s the biggest concern is how late in the season it’s coming and that it’s traveling over inland areas,” said Judah Cohen, a winter storm expert for Atmospheric Environmental Research, a commercial firm near Boston.
Many crops and plants in the south-east have started to bud because of warmer weather, Cohen said, but freezing cold temperatures expected on the back end of the bomb cyclone could cause some serious damage.
A bomb cyclone occurs when a storm intensifies rapidly by losing pressure quickly, dropping at least 24 millibars in 24 hours. In this case, computer models forecast the storm to drop from around 1,006 millibars in Alabama to be around 976 in Boston and in the 960s by the time it hits Canada, Cohen said.
There are usually several bomb cyclones a winter in the eastern US but many are over the ocean and no one is affected, Cohen said, adding that this is at least the third for the east coast this winter.
“This one is happening a little closer to land so it gets a little more attention, because if it’s just a fish storm, who cares?” Cohen said. “It’s not like it’s that unusual.”
This is likely the last bomb cyclone of the winter, at least for the south-east coast and maybe the rest of the coast too, Cohen said.
The National Weather Service issued a winter storm warning from the deep south to northern Maine.
Forecasters said high winds were possible on Saturday into Sunday, from the Carolinas to New England, and could down tree limbs and spur power outages. Powerful gusts in combination with snow could also limit visibility on roads.
While the storm was expected to move into Canada by Sunday, frigid air “crashing behind the front” could create icy road conditions in the US north-east until Sunday morning. Snow accumulation could impact travel, the Weather Channel said.
Some parts of eastern Canada were bracing for potentially damaging winds. Gusts could hit 85mph in more exposed coastal or mountain areas in Newfoundland between Saturday night and Sunday, the Weather Channel added.
A number of St Patrick’s Day parades were postponed, including events scheduled in Albany, New York, and Erie and Scranton in Pennsylvania, as well as suburban Philadelphia. A parade scheduled for Sunday in the city of Philadelphia was still scheduled to go on. The holiday falls on Thursday this year.
In Albany, after two years of coronavirus cancellations, parade co-chair Tim Carey said in a statement, “the parade committee would rather wait one more week to put this snowstorm behind us, so we can enjoy the event safely together”.
Snow in eastern Tennessee delayed by at least a day the season opening of the Dollywood theme park in Pigeon Forge. Several inches of snow in the middle of the state contributed to multiple crashes on interstate highways.