News•November 7, 2012

New Storm Bringing Snow, Flooding to Storm-Weary Coast

A little more than one week after Hurricane Sandy delivered a crushing blow to the Mid-Atlantic states and Southern New England, another significant storm is bearing down on the region on Wednesday. The storm constitutes a major threat to areas that are still picking up the pieces after Sandy, and it brings with it a new problem — accumulating snow — that is likely to affect areas where electricity has not yet been fully restored.

Infrared satellite image from Wednesday at midday, showing the storm taking shape off the Mid-Atlantic coast. Colder, higher cloud tops are in dark blue.
Credit: UCAR.

Fortunately, this storm is considerably weaker than Sandy was and it will mainly cause moderate coastal flooding, rather than the record flooding that devastated the Jersey Shore and parts of New York City during Sandy.

This nor’easter, which The Weather Channel has named “Winter Storm Athena” in accordance with their new program of naming high-impact winter storms, is forecast to bring accumulating snow to areas from northeast Maryland northward to northern New England. In the Philadelphia metro area, the National Weather Service is projecting that between 2-to-6 inches of snow will fall between midday Wednesday and Thursday morning, with the highest amounts piling up in suburban areas. Even more snow could fall in the higher terrain of Connecticut and Massachusetts on Thursday. On Wednesday morning, sleet and snow was mixing in with the rain in coastal areas, including Atlantic City, which was heavily damaged by Sandy, and New York City. This wintry mix is expected to continue throughout the storm.

While the storm will also cause coastal flooding, in most locations the storm surge will be much lower than it was during Sandy. The worst surge and most extensive coastal flooding threat will be focused on locations that are particularly susceptible to flooding due to strong north to northeasterly winds. In contrast, the maximum surge during Sandy occurred along east facing beaches. However, even the Jersey Shore will see some flooding and additional beach erosion, which is a major concern since coastal defenses were weakened or destroyed during Sandy.

“This nor’easter will have greater impact than usual because of the serious impacts from Coastal Storm Sandy,” said a National Weather Service (NWS) briefing for emergency managers. “Coastal storm defenses have been seriously compromised.”

The NWS is forecasting a storm surge of 3-to-5 feet in the New York City area, with the highest surge forecast for western Long Island Sound, and the Gardiners and Peconic Bays. The coastal flood threat at The Battery in Lower Manhattan — where during Sandy the water reached a record 13.88 feet above the typical low tide level, which included a 9.23 foot storm surge — is expected to lead to moderate coastal flooding. The main high tides of concern will occur on Wednesday afternoon, Wednesday night, and Thursday morning. Fortunately, astronomical tides are low, which should limit the severity of coastal flooding. Hurricane Sandy struck when astronomical tides were at their highest for the month, which exacerbated flooding problems.

NOAA storm surge projection for The Battery in Lower Manhattan, showing a maximum storm surge of about 3 feet, and a maximum water level of just over 7 feet above the typical low tide level.
Click to enlarge the image. Credit: NOAA.

In light of the coastal flooding threat, officials in New York and New Jersey are taking action to move people away from vulnerable coastal areas during this storm. The New York Times reported that four healthcare facilities in the Rockaways section of the city have been evacuated. The Rockaways experienced significant coastal flooding during Sandy. In New Jersey, where Sandy washed away the beaches’ protective sand dunes, leaving many areas more susceptible to coastal flooding from weaker storms such as this one.

In New Jersey, a mandatory evacuation order was issued for the parts of Middletown Township that border Raritan Bay. Brick Township, which is located along the Atlantic coast, also ordered evacuations of its waterfront areas.

As was the case during Sandy, high winds are a threat, although this time the strongest winds may not spread far inland. Gusts of up to 60 mph or higher may occur late Wednesday into Wednesday night in New York City, and the strongest winds are expected to occur across eastern Long Island as well as Cape Cod and the islands of Nantucket and Martha’s Vineyard.

Those strong winds will prevent power crews from working to restore electricity to those that are still without it after Sandy. According to the New York Times, about 90,000 customers were still without power in New York City and Westchester County, about 190,000 were in the dark on Long Island, and about 227,000 customers were still without power in New Jersey as of Tuesday.

Although the high-wind threat for inland areas is not as significant as it was during Sandy, if heavy, wet snow accumulates on trees and power lines it could result in a new round of power outages in the parts of New Jersey, New York, Connecticut, and Massachusetts that are still recovering.

This week's storm is a much more typical nor'easter of the sort that the Mid-Atlantic and Northeast typically experience several times each fall and winter. Such storms are known for their strong northeasterly winds, which is how they earned their name, and they can dump massive amounts of snow, cause damaging coastal flooding, and have other major impacts. Hurricane Sandy, however, was the result of a rare confluence of weather systems, and that storm transitioned from a purely tropical weather system to a hybrid, massive nor'easter as it made landfall near Atlantic City on Oct. 29.