All Weather News

Nor’easter: A Growing Concern in the Northeast

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With flakes flying from New York City through Washington, D.C. on Wednesday, more snow appears to be on the horizon for the I-95 corridor with a strong coastal low this weekend – potentially far more than what we’ve seen Wednesday.

City by city, here’s what we’re thinking right now:

Washington, D.C.: Snow, possibly mixed with sleet, starts early Saturday morning. A changeover to rain, depending if the coastal low tracks near enough to shore, could take place during the afternoon with a likely transition back to snow. Several inches of heavy, wet snow are possible, particularly in Loudon County, VA and Montgomery County, MD. Snow ends early afternoon.

Philadelphia: Snow starts late Saturday morning to around noon. Expect snow possibly mixing with sleet and rain, with any changeover switching back to snow before ending late Saturday afternoon. Heavy bursts of snow are possible between noon and 3 p.m. Heaviest snow totals will likely be just west and north of the city.

New York City: Snow starts around noon on Saturday, possibly mixing with sleet and snow before a potential switch back to snow after sundown. Long Island and coastal New Jersey could see some mixing. Snow ends Saturday night. Northern Westchester County, NY and Fairfield County, CT, along with the northwest hills of New Jersey, could see the biggest totals from this system.

Hartford, Connecticut: Here, all snow looks likely with the upcoming storm, although south of I-84 some mixing could take place. The heaviest snow totals could occur in the capital of the Constitution State, starting early Saturday afternoon and ending Saturday night.

Boston: Snow starts mid-afternoon on Saturday, likely staying all snow (mixing looks most likely for Cape Cod, Nantucket and Martha’s Vineyard). Snow winds down late Saturday night or early Sunday morning.

Boston and Hartford could be in line for the biggest totals with this system, but even minute shifts in the track could dramatically alter expectations.

Meteorological nitty gritty: The Global Forecast System (GFS) is trying to take the system a bit further out to sea, a scenario that would likely give Long Island, Cape Cod and southern Rhode Island the heaviest snowfall and keep the bulk of the moisture just east and south of the big cities. However, so far this season, the GFS has shown an eastward bias, trying at times to take Nor’easters too far out to sea. Thus, there could be more of a reason to side with the normally more reliable European Center for Medium Range Weather Forecasts.

The models are in agreement that this storm will rapidly strengthen. To give you an idea of how much strengthening (and how quickly), the typical benchmark for a storm “bombing out” is when it drops 24 or more millibars in 24 hours or less. The European model drops this low’s central pressure 36 millibars, while the GFS drops it by about 40 millibars over the same 24 hour time period. That sort of rapid development would indicate a very powerful system developing in a short amount of time.

For non-snow lovers, the quick movement of this system should keep totals from exceeding a foot in most places. But an intense quick shot of snow with 1-3″ per hour for a 4 to 6 hour period is possible with this system.

Again, and it needs to be emphasized, there is an enormous amount of uncertainty in regards to this forecast. This is very much a work in progress, with many important details still to iron out.

The pattern, by the way, appears to keep things active in the Northeast, with another system slated to potentially impact the region early next week.

Meteorologist Chris Bianchi

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