Possible blizzard Thursday — then temperatures plunge
The first powerful winter storm of 2018 will crash into Massachusetts Thursday morning, bringing cyclone-like winds and heavy snowfall that could knock out power and flood coastlines before the region descends once again into an arctic freeze.
The massive nor’easter, which is expected to stretch from North Florida to Maine, could dump 10 to 14 inches of snow across Eastern and Central Massachusetts and deliver wind gusts of 50 to 70 miles per hour, creating dangerous whiteout conditions.
Memorably dubbed a “bomb cyclone,” because its explosive strength will be generated by a sudden and rapid drop in atmospheric pressure, the fast-moving storm is expected to begin early Thursday and end Thursday night.
Authorities said they were most concerned about communities losing power or flooding from astronomically high tides just before temperatures fall to below zero degrees on Friday and Saturday.
“We are obviously no strangers to tough winter weather,” Governor Charlie Baker said, flanked by top administration officials at the state highway operations center in South Boston.
“But the combination of snow, high winds — and extreme cold on Friday — could lead to some very dangerous conditions, especially if there are significant power outages.”
Baker said state offices would be closed Thursday for nonemergency personnel and the state emergency management headquarters in Framingham would be activated to help authorities monitor and respond to any damage.
The governor said the state was planning to deploy high-water vehicles and utility crews on the coast, especially on the South Shore, in preparation for possible flooding and blackouts.
The National Weather Service warned that 2 to 3 inches of snow per hour could fall across Eastern Massachusetts at the storm’s peak, while winds could whip up to 70 miles per hour on the North Shore, the South Shore, Cape Cod, and Martha’s Vineyard.
“Travel tomorrow, as you might suspect, will be significantly impacted,” Baker said. “We are urging the public to please stay off the roads tomorrow unless absolutely necessary.”
He said residents who need to travel should use public transit.
The MBTA plans to run a weekday train schedule. Buses will use snow routes, and ferry service will be suspended, while the commuter rail will operate on a reduced schedule.
Baker said commuters should check the T’s website for delays. He also asked businesses to let employees work from home, if possible.
Mayor Martin J. Walsh said a snow emergency would go into effect in Boston at 7 a.m. Thursday, clearing the way for the city to begin ticketing and towing cars. Boston Public Schools will be closed Thursday, along with dozens of other school districts across the state.
The city is planning to deploy 700 pieces of equipment and 40,000 tons of rock salt, and will focus on main arteries, roadways, and public safety requests, Walsh said.
Because the snow will fall quickly, “We’re asking people to be patient with us” as plows attempt to keep pace with the accumulation.
Walsh said the bitter cold that will follow the storm may pose the biggest challenge because it will make it harder to remove frozen, ice-crusted snow banks from city streets.
Overnight lows on Friday and Saturday could plunge to 10 to 20 below zero.
Add in the wind chill, and it will feel closer to 15 to 35 below zero, the Massachusetts Emergency Management Agency said.
“This snow will be on the ground for a week, probably, because of the cold weather,” the mayor said.
“If we don’t get the main thoroughfares plowed from curb to curb, that snow could be there for a while.”
Walsh and Baker both asked residents to clear snow from home exhaust vents and tail pipes, to prevent carbon monoxide poisoning, and to shovel walkways for elderly and ill neighbors.
“We’re asking people to be careful, be safe, and be warm,” Walsh said.
Forecasters urged residents to check their flashlight and radio batteries, charge their cellphones, keep their gas tanks full, and, in the event of a power outage, use generators only in open areas away from windows.
The National Weather Service said the whipping winds coupled with high tides could cause flooding along east- and north-facing shorelines.
High tides this time of year typically range from 2 to 2.5 feet, but on Thursday, the tides are expected to rise by as much as 3 feet, especially on the South Shore and in Plymouth County.
Some flood-prone neighborhoods might be isolated by rising waters that will only slowly drain away, the weather service warned.
“A few low spots could be inundated up to 6 feet,” the weather service said. “There will be widespread flooding of vulnerable shore roads and basements.”
On the Cape and Islands, which will see rain for part of the storm, the low temperatures could also cause a flash freeze on roads and sidewalks, state emergency management officials said.
Forecasters say there might be a brief break Monday and Tuesday.
Temperatures then might even rise above the freezing mark.
Felicia Gans and John R. Ellement of the Globe staff contributed to this report.