5AM Wednesday Update: Confidence continues to go up in our forecast. All of the model guidance Tuesday night latched onto the idea of an eastward shift in the track of the coastal low, therefore shifting the axis of heaviest snow to the east. Now in the southeastern Massachusetts area, the forecast uncertainty remains high due to a very tight gradient. For example, one town is forecast to receive no snow while a town a few miles to the north and west may receive a foot. Any shift of the gradient to the northwest or southeast by just a few miles could make or break the forecast in the region.

As we head towards sunrise Wednesday, steady snow will begin to expand back from Baltimore through New York City and parts of southern New England, dropping a quick coating to an inch or so. It’s right around sunrise when we will begin to see our low begin to rapidly intensify and throw additional heavier snow back towards the coastline, along with some more mixing and rain as our low tucks itself not too far offshore. By the mid-morning hours of tomorrow, you can expect moderate to now heavy snow from the northern suburbs of Washington DC through eastern Pennsylvania, northern New Jersey and right into all of southern New England.





Around noon and through the early afternoon hours is when the worst of the storm will be felt from just north of Baltimore through Philadelphia and into New York City and Boston, where heavy snow (with some rain mixing at times) will drop snowfall rates of 1-2 inches per hour and even up to 4 inches per hour in localized areas along with gusty winds. This snow will also be heavy and wet in nature, causing more issues with trees and power lines. At this point our low will be centered just off the New Jersey coastline, and dropping quickly in pressure, already near or below 990 millibars. Places right along the coast from southern New Jersey through Long Island and southeastern Massachusetts will see a back and forth transition between heavy wet snow and heavy rain, keeping totals down. Wind will also be strongest in this region, with gusts once again surpassing 45-50 mph at times. Can’t rule out a gust to 60 mph closer to the Cape.

Moving through Wednesday afternoon and into the early evening, winds will continue to kick up and heavy snow will spread from extreme-northeastern Pennsylvania through Albany and the rest of southern and central New England. Again, snowfall rates of 1-3 inches along with gusty winds are very likely, making travel all along I-95 and westbound extremely difficult throughout the day on Wednesday. The worst of the storm then moves into New England during the evening hours, bringing similar impacts as southern New England and the Mid-Atlantic start clearing out. In Boston, recent model guidance suggests more snow than what was originally forecast, but the city is still expected to go from rain to snow by the evening. With our storm slowing down as it bombs out along the southern New England coastline, moderate snows will last well into the overnight and early Thursday morning hours from New England, dropping some of the heaviest totals from our snowstorm. In fact, it really won’t be until the afternoon and evening hours that we can say with confidence snow will wind down across northern New England. Cold and gusty winds last through Thursday across the region as a whole.

There will be a number of significant to even severe impacts from this coastal storm, of which one of the most concerning will likely be the wind. With the recent massive rain, wind, and snowstorm that we saw just a few days back, trees and power lines are already very weak. It won’t take a whole lot to bring more of these down and lead to widespread issues.





In terms of actual peak wind gusts, the strongest winds look to be right along the coastline where 40-50 mph gusts will be possible. Our legend does show gusts to 60 will be possible, but these will be very isolated and likely confined to extreme SE New England.ย Further inland just away from the I-95 corridor, gusts between 30 and 40 mph are likely, with a few top gusts near 45 mph at times. Even places all the way back inland and towards the Great Lakes will see gusty winds up to 30 or 35 mph possible, especially right along the Lake Shores.

The implications of this along with the heavy wet snowfall will be nasty. We’re thinking another large swath with millions of people impacted by scattered to widespread power outages again, especially near the I-95 corridor and NW. The best shot for power to go out will be right along the mix/rain/snow line, where the weight of the snow will be heaviest and winds will be strongest.





This includes cities like Philadelphia, New York, Hartford, Albany, Boston and Bangor. Even further inland across eastern and central Pennsylvania, as well as central New York state and northern New England, could be dealing with a good number of power outages. Again, where there is the most crossover between strongest winds and heaviest snow is where we will have the greatest power issues, and right now we believe that to be near or just north and west of the I-95 corridor.

Overall this storm will drop very significant impacts, with snow topping a foot across a solid number of places. The heaviest snowfall in the form of 12-18 inches will soon from southern Maine into the southern Green and White Mountains, western Massachusetts, western Connecticut, the Lower Hudson Valley, and into the New York City area, which is an uptick from our previous forecast.

Outside of that swath, a very widespread 8-12 inches are possible extending from eastern PA through southern and northern New England. This includes major cities like Philadelphia and Boston. The actual cities themselves will have to deal with rain mixing in at times, keeping snowfall numbers down just a bit within the 6 to 10 inch range. Boston in particular is a tough forecast due to such a tight gradient of where the rain/snow line will park itself, creating a 20-50 mile span that could make the difference between an inch or two and over a foot of snowfall. We’ll be watching that closely.





Snow will also extend back into central and western PA/New York, where a quick 2 to 3 inches of snow will be likely, with isolated amounts to 4 inches. These areas will mostly see more of a nuisance of a storm than anything else, with the snow not being quite as wet or heavy as further off to the south and east.

Taking a look at the overall impacts as a whole, we’re looking at an extremely large area of significant impacts, with even some severe impacts just west of Boston and into coastal New England. Again we go back to stressing the crossover between heaviest snow and strongest winds, as we believe this is the area that will see the best (or worst) combination of the two.

As we zoom out a bit further still, significant impacts are expect for all of I-95 from the northern suburbs of Baltimore all the way through Bangor Maine. This includes eastern PA and Albany as well, with impacts extending out well west and away from the coastline. Disruptive impacts will be felt nearly as far out as Syracuse NY, where moderate totals and gusty winds are likely. There’s a chance we even extend this out more west for tonights final update, but for now this is our best shot at what you can confidently expect.

By Thursday night the storm will be done for nearly everyone, and gusty cold winds along with heavy lake effect snow will linger behind. Several more inches of snowfall can be expected along the lakes, and may extend further to the south and east than normal. We then turn to the next potential coastal storm early next week. Stay tuned for more on that and a final storm update tonight.



Author

Currently leads business development and forecasting across all sectors and is the Founder and CEO. Pecoriello founded WeatherOptics in 2010 as a blog called, Wild About Weather, which quickly gained a following. He also launched an app in 2013 called, Know Snow, designed to accurately forecast the chances of school closings.

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