Editor's note: An updated story on the winter storm is now online.
A powerful storm is slated to plaster southern New England with blizzard conditions, hurricane-force winds, and coastal flooding, beginning on Friday and lasting through at least Saturday. Computer models that had been vacillating on whether the storm would take shape have now come into better alignment, although they still differ on crucial details that will affect snowfall totals in big cities such as Boston, Providence, and New York City. The National Weather Service has posted blizzard watches and winter storm watches across nearly all of southern New England.
A computer model projection from the European model, showing the low level winds and sea level air pressure on Saturday morning, as the nor'easter delivers a punishing blow to southern New England.
Click to enlarge the image. Credit: Weatherbell.com.
As of Wednesday afternoon, the models were calling for anywhere from 1 to 2 feet of snow in much of eastern Massachusetts, Connecticut, and northern Rhode Island. Any shift in the storm track would mean that the bullseye for the heaviest snowfall would change.
If the storm takes shape as forecast, then conditions will deteriorate across southern New England beginning Friday morning, and in much of the region, blizzard conditions — with visibility of a quarter mile or less along with sustained winds of 35 mph or greater — are likely to develop Friday night and into Saturday morning as the storm slows and rapidly intensifies just offshore of Cape Cod. Snowfall rates of 2-to-3 inches per hour are anticipated, according to the National Weather Service's Boston office.
The storm, which is setting up as a classic nor’easter in many respects, with a deepening low pressure area south of New England bumping up against a dome of cold high pressure parked over southeast Canada, is poised to be the first major snowstorm of the 2012-13 season in a region well-known for winter weather.
Early February is a notorious time of year for bringing major storms to New England, with the benchmark storm, known as the Blizzard of ‘78, occurring 35 years ago this week. That storm caused damaging coastal flooding, dumped well more than 2 feet of snow in Massachusetts, and trapped many people in their cars. In Boston, 27.1 inches of snow fell, including nearly 24 inches in 24 hours.
This storm is not expected to rival that historic event, but it does present the risk of coastal flooding from strong onshore winds, and may cause treacherous travel conditions, especially on Saturday. The National Weather Service is already warning that travel may become impossible on Saturday from southern New England into downeast Maine. Much of New York, all of Vermont, New Hampshire, and Maine have been placed under weather watches as well.
New York City looks like it will be just outside of the region of heavy snow, with the National Weather Service calling for just 3-to-5 inches of snow for the city, with much more to the north and east.
Snowfall forecast from the National Weather Service in Boston through Saturday, issued on Wednesday afternoon.
Heavy precipitation events in the Northeast, including both rain and snowstorms, have been increasing, in a trend that a new federal climate report links to manmade global climate change. In addition, rising sea levels due to warming seas and melting ice caps are already making typical nor’easters such as the upcoming event more risky, since they provide the storms with a higher launching pad for causing coastal flooding.
The NWS said there is “a good chance for at least some minor up to moderate coastal flooding” during the late Friday high-tide cycle and on Saturday morning, when astronomical high tides are higher. If the storm slows, the Saturday morning high tide could pose a greater flooding risk in Boston, the NWS said in a technical discussion posted online.
According to the draft National Climate Assessment Report released in January, even without any changes in storms, the chance of what is now a 1-in-10-year coastal flood event in the Northeast could triple by 2100, occurring once every 3 years, due to rising sea levels.