NYC Spring Nor’easter Update – Mar 20, 2018

This is a special bulletin regarding the nor’easter expected to impact the region tomorrow. This may end up being one of the biggest snowstorms ever to hit the NYC Tri-State this late in March. On to the forecast details:

Impacts: snow, heavy at times, with some thundersnow possible. Blizzard conditions possible. Steady north to north-northeasterly winds in the 20-30 mph range with gusts 35 mph+. Coastal flooding during high tide cycles with storm tides 2-3′ above normal. Widespread snowfall accumulations 8″+ in NYC, Central NJ, Lower Hudson Valley, southwestern CT. The possibility exists for more than a foot of heavy, wet snow area-wide. I think the best bet is the low-end 10″ of the official forecast for NYC that calls for anywhere between 10-18″. Expect disruptions to both commutes, in particular the PM commute. Power outages likely due to the combination of accumulating heavy wet snow and windy conditions downing trees and/or power lines.

Timing: conditions deteriorating overnight. Snow beginning early in the morning in NYC (as early as 5-6AM possibly), later in the morning north of I-287. Heaviest snow during the day, especially in afternoon hours when lift is maximized. Snowfall rates of 1-2″/hr or more possible during the afternoon. Snow tapering off overnight, probably ending by midnight.

Discussion: this storm is unlike the previous two that struck the area. The surface and near-surface is colder than what it was at the outset of the last two storms. This will aid in snow sticking quickly, despite the high sun angle this late in March. The storm track has been trending westward but right now looks to be directly over the 40°N/70°W benchmark, a track that favors heavy snow over the area. The bust potential for a snow total below 8″ is still there, but even a snowfall of 5-6″ would still be substantial for this time of the year!

Focus on the storm track of the deeper low, the one that has the orange and brown plotted storm center positions.

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