The forecast still remains very uncertain, unfortunately, for the Northeast in terms of how this incoming storm will impact the region. Hopefully we have more information and better confidence to release a first forecast by the end of the day Wednesday or Thursday morning. We’re going to break down the different impacts this multi-faceted storm and what’s still uncertain about each threat.



Low Pressure:

A first area of low pressure will develop today over the Central Plains and will track toward the Great Lakes by Friday. We’re then going to see the energy associated with this low move off the Northeast coast, fueling the development of a new low pressure. There are timing differences between when this happens. The European (EURO or ECMWF) model is a stronger and quicker scenario with the coastal low taking over Friday morning. Meanwhile the most recent runs of the American (GFS) and NAM models are slower with that transfer of energy and they want to keep the storm around through the end of the day Saturday. They bring the center of the low into southern New England, then they want the storm to make a counter-clockwise loop before heading out to sea.

Precipitation Type:

The first low pressure will bring a shield of rain into much of the Mid-Atlantic and Northeast Thursday into Thursday night. By the end of the day Thursday, rain will impact areas from Lake Erie through the New York City area, especially south. In terms of snow, there won’t be a significant air mass pushing cold air into the region, but there will be enough cold air for some inland areas to experience snow and potentially heavy snow. Snow is forecast to fall Thursday into Thursday evening for portions of the southern Great Lakes region, including southern Michigan and northern Indiana and Ohio.




Then into the overnight hours, that rain will move further north and east, impacting portions of southern New England. This is when the uncertainty becomes very high. The EURO model shows a more impactful scenario with a widespread snow breaking out across western Pennsylvania, most of New York State outside of the Lower Hudson Valley, New York City, and Long Island, and portions of northern New England. Snow may also make it as close to the coast Thursday night as northern New Jersey and the Berkshires of western Massachusetts and northwestern Connecticut. We want to note that the EURO model has been more consistent with this storm while the GFS and NAM models have been showing different outcomes run-to-run. As of the latest runs, the GFS makes this storm a rain event for most of the Northeast Thursday night but the NAM is actually is better agreement with the EURO model of where snow may fall.

Now taking a look at Friday, the uncertainty couldn’t be any higher. Please bare with us on this storm. There are no forecasters who know how exactly this storm will impact the Northeast. Our coastal low will likely takeover some time Friday as energy transfers offshore. The EURO and NAM models remain in pretty good agreement, bringing colder air toward the coast in the New York City area, so snow may make it as far east as the New Jersey coast (especially the northern half of the state), New York City, and western Connecticut. This snow may also be heavy, so the snow could come down hard and quick, making it easy for the snow to accumulate in the marginal temperatures. Meanwhile for the rest of the Northeast, we’re thinking snow will persist or move into much of Pennsylvania with the exception of the Philadelphia area, most of New York State, and portions of the higher elevations of northern New England. Based on the track of the low pressure, warmer air may be able to sneak into the region as well as continuing to keep the rain around much of southern New England and Long Island.




Then on Friday night, this is when there is the best chance for snow but when the models diverge even further from agreement. The NAM becomes the coldest model, showing a widespread snow across portions of New York, Pennsylvania, and most of central and southern New England away from the immediate coast. Snow showers may even make it into southern New Jersey and the DelMarVa as colder air intrudes from behind the storm. The European model, however, keeps the warmer air around in this region and suggests that the precipitation entirely clears out of the Northeast early Saturday morning. The GFS is a bit slower in terms of the departure time compared to the EURO, but they show a pretty similar scenario as the EURO mode.

On Saturday, it’s unsure if our coastal storm will be out to sea yet or will begin to make that move. Don’t be surprised if rain and/or snow showers are still around, especially in southern New England.

To sum this up, a big question that has been circulating around is whether this will be a major concern. Based on some of the ensemble model guidance we have been looking at, there is the chance for a major snowstorm for much of the Northeast, including New York City and Boston. While the chance for that to happen is low, it’s not zero. Also, another concern is inland flooding, especially in southern New England. It’s been a very wet February, and several inches of rain may fall with this storm.

Here’s our current thoughts on a map. Note that ‘Significant Snow Possible’ means that that’s where there’s the best chance for at least half a foot of snow and potentially up to two feet:

Wind:

Based on the intensity and the track of the coastal storm, that will determine how much wind you will deal with. Basically, the stronger the storm and closer to the coast it is, the stronger the winds will be. We are certain that the strongest winds will be found at the coast, especially in southeastern Massachusetts.




Winds will be relatively calm on Thursday but will begin to ramp up Thursday night with widespread wind gusts of 20-30 mph from the Great Lakes through the Mid-Atlantic and Northeast. There will be pockets of stronger winds of up to 50 mph, which may affect the Lake Erie area southward through the Appalachian chain. As we get into Friday and Friday night, higher winds will begin to shift into the Northeast while dwindling in the Great Lakes. By this time, widespread wind gusts of 30-45 mph is expected across the region. Again, there will be pockets of stronger winds with gusts potential as high as 60 mph. By this magnitude, isolated to scattered power outages can be expected from central New England through the Mid-Atlantic, including as far south as the Outer Banks of North Carolina. The winds will remain gusty throughout the weekend along the coast as our storm pulls away. Gusts will remain as high as 40 mph for this area; maybe as high as 55 mph on Saturday in southeastern Massachusetts.

Coastal Flooding:

Wave Heights This Weekend

Coastal flooding is the most certain component with this forecast. We know there is going to be a strong strong and that there will be above-normal tides this time of the year due to the full moon Thursday night. That will make for really a worst-case scenario for the Mid-Atlantic and New England coasts. Possibly up to four or five different high tide cycles will be impacted by coastal flooding, and some of the model guidance is suggesting some areas deal with moderate to even major coastal flooding. This is a big concern that needs to be watched very closely.

There will also be large waves generated by this storm with waves up to 40 feet offshore this weekend. This will make for elevated surf through early next week along most of the East Coast. Waves may surpass 10 feet along portions of the Northeast coast, so please don’t go into the chilly water.




We hope you find this update helpful and hopefully we can release an official forecast later today or Thursday morning.

Author

Jackson is COO and Head of Content and Strategy of WeatherOptics. He also designed his own website and created the local company, Jackson's Weather. He has been forecasting the weather for southwestern Connecticut since March of 2015. He will major in Meteorology and Broadcast Journalism at the University of Miami in Fall 2018.

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