The fourth nor’easter of this month alone is set to slam portions of the Mid-Atlantic and New England with heavy snow, gusty winds, and coastal flooding over the next 48-72 hours. This is a challenging forecast based on the different precipitation types that will along with snow, but we’re ready to discuss our thoughts and what we think the most likely outcome is for this storm.
A classic transfer of energy from a weakening low pressure approaching the southern Appalachian Mountains to a new and developing low pressure just off the Carolina coast will occur Tuesday night. Our nor’easter will then track toward the north while hugging the New Jersey and DelMarVa coasts before taking an eastward turn toward the 40/70 benchmark and moving very close to these coordinates (40°N, 70°W) Wednesday night. This is a slow moving storm, which will allow for greater impacts. Even though this storm will feature a slower forward speed compared to the previous nor’easters this March, the storm will not rapidly strengthen into a “bomb cyclone.” This is good news because coastal flooding won’t be as terrible as it could have been and winds will not be as strong. However, many areas from the Mid-Atlantic coast up through New England can still expect minor to moderate flooding. While no bomb cyclone, our storm will start off with a pressure between 990 and 995 millibars Tuesday night near the Outer Banks of North Carolina, and then bottom out between 980 and 985 millibars by Wednesday night as it nears the benchmark.
Let’s talk about the impacts: much of the precipitation associated with the low pressure over the Appalachians will begin as rain across the Mid-Atlantic region. Further west, however, freezing air at the surface will allow for freezing rain during the day from central Indiana through central or southern Ohio. This may be an all-snow event as soon as the precipitation begins in northeastern West Virginia into south-central Pennsylvania. Then during the afternoon hours, the northern shield of the precipitation will creep to the north, nearing the New York City area by the evening, although dry air aloft will prevent any of the precipitation to fall until early in the morning on Wednesday. Back to the south in the Washington, D.C. and Philadelphia areas, the rain will begin to changeover to sleet and some freezing rain. To the west in the eastern Ohio Valley, rain will move in during the afternoon hours and will then changeover to snow Tuesday night while the western Ohio Valley starts and ends with snow.
Speaking of Tuesday night, this will become a snow event for the Ohio River Valley and the northern Tennessee River Valley as well as in the central Appalachians. Back toward eastern Virginia up I-95 through Southern New England, sleet and some freezing rain mixed in will continue. Rain will still be falling at the immediate coast.
Wednesday will be the big day for this nor’easter, and it will be a nor’easter by this point following the successful transition of energy to the coast. The sleet will changeover to snow across Virginia up through Philadelphia and areas to the west. To the east of I-95, primarily in New Jersey, the sleet will take a longer time to transition to snow. Expect that to happen by the late-afternoon. Meanwhile in the Appalachians and Ohio and Tennessee Valleys, the snow will begin to lighten up in intensity and taper off as the day progresses. To the north and east in the New York City area and southern New England, snow will move in from south to north, beginning for this entire region by around noon. The morning commute should be fine if traveling I-95 between New York and Boston while from New York through Washington, D.C. it will become messy. For the evening commute, however, it is expected to be a mess for the entire I-95 corridor. Temperatures will be marginal (near freezing to as low as the upper 20s), so the road treatments should keep the major roads in fairly good shape. By the evening hours, snow will be falling from coastal Maine through eastern Virginia. The fact that this storm is impacting the entire Northeast megalopolis during a weekday will make this a high-impact event. Once you experience that transition to snow, it will be falling at a moderate to perhaps heavy intensity (0.5-1.5 inches per hour) for a very widespread area. This is because of large scale ascent or rising of the air. Instead of thin mesoscale snow bands that set up, like with the past storms this winter, the model guidance is hinting at a larger but lighter band that sets up compared to very heavy, discrete bands that lead to large snowfall variations.
Then overnight Wednesday, our storm will begin to pull away from the Mid-Atlantic coast. Expect improving conditions in the Appalachians and the Mid-Atlantic region during the evening hours or the first half of Wednesday night. This will become more of a New England event by this time. Snow is expected to continue to fall through at least half of the night for New York City, Long Island, and southern and eastern New England. This will be mainly an all-rain event, however, for most of Cape Cod and the islands of Massachusetts.
By Thursday, millions in the Northeast will wake up to snow cover and clearing skies. The only area that will continue to experience falling snow Thursday morning is eastern Maine. That snow will then end by the mid-afternoon as our nor’easter moves into the Canadian Maritimes.
We mentioned how minor to moderate coastal flooding is expected due to this slow-moving storm. Gusty winds are also expected with the general theme of gusts up to 20-30 mph in the Mid-Atlantic and inland New England. Once you get to the coast, peak gust of up to 35-45 mph will be more commonplace. The top gusts will likely be recorded on the Cape and the islands, which is quite typical with these nor’easters. This is where gusts may top 50-60 mph. Therefore, power outages are possible along the coast, but they will be isolated in nature. Due to the lighter snow and the higher snowfall ratios instead of a heavy, wet snow, this should prevent widespread power outages from occurring.
We know you all want to know how much snow will fall. Keep in mind our forecast below is still subject to change. The toughest forecast is for the Mid-Atlantic, especially along and east of I-95 where temperatures will be near freezing and there will be several hours of sleet at the onset of the snow. Also notice the super sharp northern snowfall gradient. Any further shifts in the track of this nor’easter could put more locations at play for snow or fewer. Therefore, minor adjustments to this snowfall forecast is expected.
Here’s the forecast for select cities:
- Bangor, ME: 3-6 inches
- Boston: 3-6 inches
- Hartford: 6-12 inches
- New York City: 3-6 inches
- Philadelphia: 3-6 inches
- Baltimore: 3-6 inches
- Washington, D.C.: 3-6 inches
- Richmond: 1-3 inches
- Pittsburgh: 6-12 inches
- Indianapolis: 3-6 inches
Stay with WeatherOptics through the tracking of this nor’easter for any new changes.