A third in a series of potent coastal storms appears to be about to impact the northeast, bringing another round of wind-whipped heavy snow to the region. This latest Nor’Easter has prompted the National Weather Service to issue Winter Storm Watches and Warnings over land and Hurricane Force Wind Warnings for off-shore waters. After being hit hard by the March 2 and March 7 storms, residents will need to prepare for another round of snow and wind over the next 72 hours.
Unlike recent snowstorms, the snow type from this system should be a bit more powdery. Set-up as a classic winter nor’easter with a cold blocking high pressure to the north, the storm should phase and explode off the northeast coast, deepening below 970mb as it does so. This rapid intensification is known as bombogenesis, earning the system a “bomb cyclone” moniker.
When examining the forecast scenario, meteorologists were originally concerned that a southern stream system may intensify as it exits the Mid Atlantic coast. Such a solution had two storm tracks; heading out to sea fairly harmlessly, or intensifying and moving up the coast, bringing wind whipped precipitation in its path. However, the southern stream shortwave has no trended much slower and farther south than originally thought. This is allowing a northern stream system the opportunity to phase and cause a surface low to rapidly deepen as it passes off the New England southeast coast. Rather than deal with the potential of a potent Sunday night/Monday morning system, it now appears most of the action in the northeast will occur Monday night into Tuesday morning.
As with previous storms, the rain-snow line will be very close to the I-95 corridor between Washington, DC and New York City, NY. In this area, temperatures will also be marginally supportive of falling and accumulating snow. Across portions of the Washington, DC and Baltimore, MD metro areas, along with much of the DelMarVa Peninsula, wet snow flakes may fall but will struggle to accumulate. Further south and west where the main southern storm is and further north and east where the bomb cyclone will intensify, accumulating snow will be likely. At this time, 3-6″ of snow is expected over eastern West Virginia and western Virginia, with 6-12″ possible in the higher mountains there. In the northeast, 3-6″ is expected across the eastern half of upstate New York, the New York City metro area, and north coastal New Jersey. Further east, 6-12″ is expected for eastern Connecticut, Rhode Island, eastern Massachusetts including Boston, much of New Hampshire, and the southern two-thirds of Maine. An area of 12-18″ is expected over southeastern Maine and the New Hampshire coast.
Should the storm intensify more than currently forecast or hugs the coast more than it is expected to at this time, snow totals could increase for New Jersey north and eastward. However, a closer-to-the-coast path could also bring in some non-snow precipitation into the coastal region, which would reduce snowfall amounts at the immediate coast and 5-10 miles inland.
In the Mid Atlantic, expect rain and rain/snow mix falling on Monday to change to plain snow by Monday night. Snow will continue through Tuesday morning, before wrapping up from southwest to northeast. However, unlike the last two systems that quickly left the region, this storm will linger around a bit, with disturbances rotating around from behind it. As such, snow shower activity will persist for a day or two after the storm exits for higher elevations of the northeast from northeastern Pennsylvania and northwestern New Jersey to points north and east.
Beyond snow, this storm is bringing additional coastal storm threats: wind and coastal flooding. Coastal flooding appears to be minor south of New York City for this storm, with minor to moderate flooding possible north of there up the New England coast. Winds will be gusty, although will be mainly confined to coastal regions.
In this set-up, there is also the possibility of thundersnow in southeastern New England. Remember: when thunder roars, head indoors; lightning can kill in any season, including in wintertime snow storms.