By Thursday, the exploding storm will, in many ways, resemble a winter hurricane, battering easternmost New England with potentially damaging winds in addition to blinding snow.
Unforgiving cold has punished the eastern third of the United States for the past 10 days. But the most severe winter weather conditions yet will assault the area late this week.
A brutal winter storm scattered a wintry mix of snow, sleet and freezing rain from normally balmy north Florida up the Southeast seaboard Wednesday. The National Weather Service said the snow and freezing rain was expected to spread up the coast to the Carolinas, amid warnings that icy roads and low visibility could make driving treacherous. Accumulations of 8 to 13 centimetres were possible in eastern North Carolina.
By Thursday, the exploding storm will, in many ways, resemble a winter hurricane, battering easternmost New England with potentially damaging winds in addition to blinding snow.
Forecasters are expecting the storm to become a so-called “bomb cyclone” because its pressure is predicted to fall so fast, an indicator of explosive strengthening. The storm could rank as the most intense over the waters east of New England in decades at this time of year.
In the storm’s wake, the motherlode of numbing cold will crash south — likely the last but most bitter in the series of brutal blasts since Christmas Eve.
Georgia Gov. Nathan Deal declared a state of emergency through Friday for 28 counties because of the frigid weather.
The National Weather Service said up to 2.5 centimetres of snow could fall as far south as Tallahassee, Florida. In fact, snow began falling in Tallahassee early Wednesday — a rare occurrence in the north Florida city.
In Central Florida, the state’s largest theme parks announced that water attractions such as Disney’s Typhoon Lagoon, Universal Orlando’s Volcano Bay and SeaWorld’s Aquatica were closed Wednesday because of the cold snap.
In Brunswick, Georgia, on the Atlantic Coast, law enforcement agencies reported freezing rain and ice on bridges early Wednesday. The icy conditions also were hampering early morning travel in Florida, as authorities were forced to shut a stretch of Interstate 10 east of Tallahassee.
In other parts of the U.S., dangerously cold temperatures have been blamed for at least a dozen deaths as well as freezing a water tower in Iowa and halting ferry service in New York.
Farther inland in the mid-Atlantic, near Interstate 95, the storm’s exact track will be highly consequential. Current computer models suggest most — if not at all — snowfall will occur east of Washington and Baltimore Wednesday night into early Thursday. But small shifts to the west could bring some snow to these cities.
To the north, Philadelphia and New York have a better chance for a coating of snow, but — unless the storm edges closer to the coast — the more significant snows should remain to their east from Atlantic City to eastern Long Island where at least 7 to 15 centimetres could fall late Wednesday to late Thursday.
By the time the storm reaches the ocean waters east of Long Island and eastern New England Thursday, it will be explosively intensifying. The storm’s central pressure will have fallen 55 millibars in just 24 hours — an astonishing rate of intensification.
“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,” writes 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.”
Winds will crank in response to this pressure drop, howling to at least 48 to 80 km/h along the coast. Winds will be considerably stronger over the ocean — exceeding hurricane force — where enormous waves will form.
In Boston, the Weather Service is predicting not only 10 to 17 centimetres of snow but also winds strong enough to bring down trees branches. Throughout eastern Massachusetts and eastern Maine, the combination of wind and snow could create blizzard conditions, especially if the storms wobbles west.
The National Weather Service issued wind chill advisories and freeze warnings Tuesday covering a vast area from South Texas to Canada and from Montana through New England.
Indianapolis early Tuesday tied a record low of -24 Celsius for Jan. 2 set in 1887, leading Indianapolis Public Schools to cancel classes.
The storm’s enormous circulation will help draw several lobes of the polar vortex, the zone of frigid air meandering the North Pole, over the mid-Atlantic and Northeast by Friday and Saturday. Wicked cold air sourced from Siberia, the North Pole and Greenland will all converge on the region.
Temperatures are forecast to be 20 to 40 degrees Fahrenheit below normal, the coldest of the winter so far. Most locations in the mid-Atlantic and Northeast are predicted to set record cold high temperatures on Friday with highs in the single digits and teens.
On Saturday morning, sub-zero cold is forecast over almost all of New England, with single digits in the mid-Atlantic. Winds, gusting to 48 km/h, will make these areas feel 10 to 20 degrees Fahrenheit colder.
Finally, after one of the most intense cold spells of such duration on record in parts of New England — including Boston, temperatures are forecast to gradually thaw by early next week.