December 17, 2013 Storm Summary

December 17, 2013 Snow

12.17.13_1928The final snowstorm of the cold and stormy 10-day period affected the region on December 17, with an initial round of moderate snow during the morning, followed by additional light-moderate snow in the afternoon, mixed with sleet and rain near NYC and Long Island. Light to moderate snow totals were recorded across the NYC area with at least 2-4 inches of snow for most locations, higher north/west of NYC, bringing snow totals in December 2013 to well above average from NYC and further north/west.

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December 17, 2013 Storm Archive

NWS Regional Radar
WPC Surface Analysis


Storm Synopsis

dec17trackThis storm was an Alberta Clipper-type system that originally developed over western Canada, then diving southeast towards the Midwest and Great Lakes region on December 16, where it produced widespread light to moderate snow, but with a lack of a well defined surface low pressure center. Early on the 17th, precipitation from the clipper entered the northeast US region, where a quick moving round of light snow fell in the morning.

As the mid level shortwave trough began to amplify and gain a negative tilt while entering the region, a surface low pressure began to develop near eastern New Jersey during the middle of the day on the 17th, tracking towards eastern Long Island by the evening while starting to intensify, leading to precipitation redeveloping and intensifying over the northeast US. Slow intensification continued to occur overnight as the broad low pressure area began to consolidate off the northeastern US coast, with a 1000 mb low pressure off the coast of Nova Scotia by the morning of the 18th. More rapid deepening occurred throughout the day, with a minimum pressure of 986 mb by the time the low moved out of Nova Scotia in the evening.



Forecasting The Storm

December 12 – Snow, Ice, Rain Expected Saturday
December 13 – Significant Snow, Ice Tomorrow
December 15 – More Snow on Tuesday
December 17 Storm Updates


Post-Storm Analysis

This section will be added soon.



Storm Timeline in the Northeast

Regional radar image from 6:18 AM EDT 12/17, from the National Weather Service. Widespread light snow covered the area, but with little precipitation elsewhere.

A very cold air mass was present over the region prior to the arrival of precipitation, especially over the interior northeast US; while NYC and the coast fell into the low 20s for lows, northwest NJ and interior SE NY crashed to nearly zero degrees, with sub-zero temperatures further inland. A band of light snow associated with the clipper system spread into the region early on Tuesday morning, 12/17, moving through NYC, northern NJ and SE NY between 4-7am and Long Island/south CT between 6-10am, with up to an inch of snow observed. Little precipitation was observed elsewhere, however, with a lack of an organized surface low pressure during the morning hours.


Regional radar image from 2:28 PM EDT 12/17, from the National Weather Service. Precipitation from the coastal low developed across Pennsylvania and New Jersey, mixing with rain/sleet in NYC and Long Island.

After a brief break with scattered snow showers behind the front end of the system, the low pressure began to develop near coastal New Jersey by the late morning and early afternoon hours, with widespread precipitation beginning to develop over eastern Pennsylvania and New Jersey by 11am-1pm as the initial band of snow spread into central NY state and Massachusetts. Temperatures significantly varied across the NYC area, depending largely on the morning lows and on the proximity to the coast; interior locations, which had low temperatures near zero, only warmed up into the mid-upper 10s for highs, remaining with plain snow, while NYC and Long Island, which generally fell into the low 20s in the morning, warmed into the low 30s with a changeover to rain and sleet, while eastern Long Island saw temperatures surging into the mid 40s in the early afternoon for a short period of time before falling back into the 30s. Other parts of the area saw moderate snow, with areas of heavy snow spreading into the Hudson Valley and Connecticut. Precipitation then changed back to snow for NYC and parts of Long Island before ending between 3-5pm from NYC and west, and 5-7pm over Long Island/southern CT.



Storm Impact and Precipitation Totals

12.17.13_snowThe storm affected the region just 2-3 days after the preceding significant snowstorm, adding onto the present snow pack across much of the region. Snow accumulations over 1 inches were reported across most of the northeast US, with an axis of 4-8 inches of snow from southeast NY into central New England and coastal Maine. The highest totals were observed over the immediate coast of Maine, with a narrow axis of 8-14 inches of snow. As with the preceding storm, frigid temperatures covered the region ahead of the precipitation shield, with temperatures in the negative and slightly positive single digits as snow began to fall in the interior Northeast, failing to even reach 10 degrees in some locations throughout the duration of the storm.

In the NYC area, as with the previous storm, a mix of precipitation types was observed, ranging from frigid temperatures and snow inland to a wintry mix and warmth near the coast. Snow accumulations of at least 2-4 inches, locally up to 5″, were observed in northern NJ, SE NY and southern CT, with 1-3″ in Long Island and NYC. Interior locations remained as plain snow, while NYC and Long Island saw mixing with sleet and rain before changing to snow as the system moved out. Combined with the previous several storm systems, this brought December snowfall to above average across much of the area, with Central Park’s month to date snowfall at 8.6″, higher than the entire winter snowfall of 2011-12.

Below is a list of selected snow reports across the area from the National Weather Service, listed by highest total from each county:

Northern NJ:
3.0″ – Franklin Lakes, NJ (Bergen)
2.1″ – Harrison, NJ (Hudson)
2.0″ – Newark, NJ (Essex)
1.4″ – Union, NJ (Union)

Southeast NY:
4.8″ – Washingtonville, NY (Orange)
4.0″ – Eastchester, NY (Westchester)
3.2″ – Cold Spring, NY (Putnam)
2.4″ – Suffern, NY (Rockland)

New York City:
1.9″ – Greenpoint, NY (Brooklyn)
1.6″ – Bronx, NY (Bronx)
1.5″ – Astoria, NY (Queens)
1.1″ – Central Park, NY (Manhattan)
0.7″ – Dongan Hills, NY (Staten Island)

Long Island and South CT:
4.5″ – North Brandford, CT (New Haven)
4.0″ – Middletown, CT (Middlesex)
3.6″ – Bridgeport, CT (Fairfield)
2.5″ – Niantic, CT (New London)
1.5″ – East Northport, NY (Suffolk)
1.3″ – Albertson, NY (Nassau)

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