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Major March storm to lash Northeast with heavy snow, rain and wind

Heavy, wet snow combined with strong winds could cause impassable roads and widespread power outages in interior areas as the storm gains strength Tuesday

National Weather Service (NWS) snowfall forecast through Wednesday morning. Although some may fall after this, additional accumulation should be generally insignificant. (Pivotal Weather)
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A high-impact winter storm is brewing and preparing to wallop much of the Northeast, from the northern Mid-Atlantic to New England, with rain, heavy snow and powerful winds Monday night through Wednesday. What was a minor swirl in the atmosphere off the Carolina coast Monday morning will rapidly explode into the largest snowstorm of the winter for some, and a heavy rainstorm with possible flooding for others.

About 20 million people across 11 states in the Northeast, particularly New York state and New England, are covered by winter weather alerts. A heavy, wet snowstorm — combined with powerful gusts — will probably shut down swaths of the region during the storm’s peak. The weight of the snow on trees and power lines could also result in widespread power outages.

For most big cities along the Interstate 95 corridor, the snow-starved winter pattern is set to largely hold, with much of the urban Northeast probably missing out on major snow. Significant snow accumulations should stay mainly north of New York City, while Philadelphia should see some rain followed by cold wind, and around Washington it’s mostly just cold wind. The potential exception is Boston, which could pick up a half-foot or so of pasty snow at the tail end of the storm.

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The storm’s center was developing just offshore to the east of Hatteras, N.C. It will continue to develop slowly much of Monday before more rapidly intensifying at night and into Tuesday while flinging heavy precipitation into the Northeast.

The storm’s pressure — a measure of its intensity — is forecast to fall from 1004 millibars Monday to at least 980 millibars Tuesday evening, according to the National Weather Service’s Weather Prediction Center. The lower the pressure, the stronger the storm. The projected pressure fall would come close to the criteria for the storm to be classified as a “bomb cyclone,” which requires a drop of 24 millibars in 24 hours.

A long-duration storm with heavy, wet snow

Regardless of its exact pressure, the storm will draw tremendous amounts of moisture over the Northeast. Some interior regions are likely to see a foot or more of snow. Amounts could vary dramatically depending on elevation, which is typical of mid-March snowstorms, with up to two feet possible at the highest elevations. A difference of just a few hundred to a thousand feet can be a game changer for how much snow piles up.

“Heavy snow rates (2 inches plus per hour) and strong winds will produce dangerous to impossible travel,” the Weather Service wrote early Monday morning. “The heavy-wet nature of the snow, combined with max wind gusts up to 50 mph, will result in scattered to widespread power outages and tree damage.”

Snowfall forecasts as high as 24 to 30 inches or more are presently focused on the southeastern Catskill Mountains in New York, about a three-hour drive northwest from New York City. Totals of 12 to 24 inches are anticipated in the Berkshires and Litchfield Hills of Southern New England and the mountainous terrain of southern Vermont and New Hampshire. Twelve to 15 inches are in the forecast for Worcester, to the west of Boston, and higher elevations in that area.

“This will be a long duration and high-impact snow event,” wrote the National Weather Service office in Albany.

It’s not just the snow, but also the wind that will have major impacts. Gusts are forecast to reach as high as 45 to 55 mph in the Catskills and elevated areas of Southern New England.

The snow will be heavy, wet and clingy due to high moisture content and temperatures near or only a little below freezing. This can add significant weight to the snow, leading to failure of trees and weaker structures.

Even in the areas with the highest snowfall forecasts, temperatures are expected to be in the upper 20s or lower 30s at their coldest. Because of the strong winds, though, wind chills should mainly be in the teens and 20s Tuesday and in the teens Tuesday night.

Eastern portions of the snowfall area may see the most snow of the season so far. From the Hudson Valley of southern New York to southeast Massachusetts, many locations are running two to three feet below average for snowfall this winter.

Rain, wind and coastal impacts

Closer to the coast, precipitation is likely to fall mainly as rain.

The Weather Service is forecasting less than one inch of snow for New York City and similar totals across much of Long Island and coastal Connecticut. In locations that see all or mostly rain, 2 inches or more are possible, which could lead to some brief and localized urban or small stream flooding. Central to southern New Jersey and areas toward Cape Cod should also remain mostly rain.

A high-wind warning is up from Tuesday morning through Wednesday morning for most of the Massachusetts shoreline, including parts of the Boston area, as well as Cape Cod and nearby islands. Northeast winds of 30 to 40 mph are expected, with gusts to 65 mph. Wind speeds like these will probably down trees and cause power outages.

One fortunate aspect of the storm timing is that it does not coincide with unusually high tides. Nonetheless, the storm will span multiple high tide cycles with widespread minor coastal flooding anticipated. Beach-battering waves, especially in the areas under wind warnings, are likely as well.

The worst of the storm should occur Monday night through Tuesday night, but flurries and light snow could continue for parts of New England on Wednesday as the system crawls eastward. By Thursday, the only remaining impacts should be gusty but diminishing winds.

A surge of warmer air late in the week and potential for rain by around the weekend should help keep the snow from sticking around too long.