Dec 26-27, 2012 Storm Summary

December 26-27, 2012 Snow, Rain, Wind

dec27radarAfter a warmer and drier than average start to December, two winter storms affected the region. The first was on December 26-27 as a strong low pressure tracked through the Ohio Valley with a secondary low developing further east and moving up the coast, producing widespread heavy snowfall in the interior Northeast up to 8-16 inches, and a mix of heavy snow, rain and strong wind gusts in the NYC area.



December 26-27, 2012 Storm Archive

December 21 – Winter Begins With 2 Snow Potentials
December 23 – Three Storms Coming Up
December 24 – Two Storms, Then Cold
December 25 – Final Storm Forecast
December 26 Storm Updates

Radar Archiveto be added soon


Storm History

dec27trackThe low pressure system originated in the Gulf of Mexico region on December 25, producing widespread heavy rain and some interior snowfall. The low slightly intensified on Wednesday, 12/26, as it tracked to the northeast through Tennessee and eastern Kentucky, with a minimum pressure near 996 mb. During the afternoon and evening hours, a secondary low pressure began to develop over South Carolina, tracking northeast towards the Virginia coast where it became the dominant low pressure. The low continued to track northeast just off the coast throughout Thursday, 12/27, passing near the eastern tip of Long Island and Cape Cod on Thursday afternoon while its minimum pressure fell to near 988 mb. The storm exited the region on Thursday night, tracking towards Nova Scotia and Newfoundland.


Forecasting The Storm

This section will be added soon.


Storm Observations

Radar image from 4:58 PM 12/26, from the National Weather Service, showing a band of heavy snow over the northern suburbs of NYC, which fell as rain over Long Island, as precipitation started to fall over CT.

dec27radarPrecipitation initially spread into NYC and northern NJ on 1-2 PM on Wednesday, 12/26 and Long Island/CT by 4-6 PM. With temperatures cold enough, precipitation at the start of the storm fell as snow from NYC and further northwest, but as rain in Long Island. The snow was light and short lasting in NYC, quickly changing to rain in the mid afternoon hours with little accumulations. The rest of the area, meanwhile, saw snow steadily intensify through the afternoon hours. A band of heavy snow moved through northern NJ and SE NY by 4-5 PM and southern CT in 5-7 PM, which is when most of the accumulations in the north/west suburbs took place.


Radar image from 11:18 PM 12/26, from the National Weather Service, showing snow covering most of the interior Northeast, with heavy rain spreading into New Jersey, falling as snow/sleet in far NW NJ. Thunderstorms can be seen over south NJ.

0418The coastal low pressure continued to develop and track towards New Jersey in the afternoon and evening hours, with warmer temperatures slowly spreading in from the south. Behind the band of heavy snow in the late afternoon, the north/west suburbs began to change over to sleet/freezing rain and later on rain in the evening, with the transition mostly complete by 10 PM. By then, except for interior locations, the rest of the area observed a steady moderate to heavy rain with increasing winds. Northwestern locations over NW NJ and interior SE NY continued to see heavy snow in the evening, lightening up around 10-11 PM with another round developing after midnight, but this time with sleet and freezing rain occasionally mixing in. The steady precipitation mostly ended by 3 AM, with additional scattered showers continuing through Thursday morning when the low pressure tracked over eastern Long Island.


Storm Impact in the Northeast

The map below shows estimated snow totals from the storm across the region, based on storm reports from the National Weather Service. Actual totals may be slightly higher or lower than shown below.

dec27snowWidespread heavy snow fell with this storm across the Northeast, with a large axis of 8 to 14 inches of snow in NY state and central-northern New England, with the highest totals generally found in eastern Maine. The I-95 corridor between Washington DC and Boston served as a rough borderline between notable snow accumulations and little to no accumulations, with a sharp gradient near NYC and west of Boston. A relatively tight pressure gradient set up between the coastal low pressure and the high pressure to the north, with breezy winds observed in parts of the region and especially near the coast, where gusts as high as 45-65 mph were recorded.

In the NYC area, impacts differed significantly between interior and coastal locations. Towards NW NJ and SE NY, most of the storm fell as snow, with sleet, freezing rain and rain mixing in towards the end of the storm. At least 4 to 8 inches of snow were recorded in these areas. In the north/west suburbs of NYC and southern CT, at least 2 to 4 inches of snow accumulated in the afternoon hours prior to the changeover, with another 1-1.5 inch of rain falling in the evening and overnight hours. Heavy rain fell in NYC and Long Island with 1-2 inches, accompanied by strong wind gusts up to 40-55 mph, with gusts locally as high as 60-70 mph in Suffolk county.

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:
4.5″ – West Milford, NJ (Passaic)
3.3″ – Oakland, NJ (Bergen)
2.0″ – Roseland, NJ (Essex)

Southeast NY:
6.5″ – Montgomery, NY (Orange)
5.5″ – Somers, NY (Westchester)
4.5″ – Mahopac, NY (Putnam)
4.0″ – Suffern, NY (Rockland)

New York City:
No snow accumulations

Long Island / South CT:
5.3″ – Wolcott, CT (New Haven)
4.0″ – Danbury, CT (Fairfield)
3.2″ – Lisbon, CT (New London)

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