December 29, 2012 Snowstorm
After a warmer and drier than average start to December, two winter storms affected the region on December 26 and 29. On the 29th, two areas of low pressure simultaneously tracked northeast, one in the Ohio Valley, and another near the coast, with the coastal low becoming dominant while producing heavy snow for eastern Long Island and CT. Snow totals generally ranged from 2 to 5 inches from NYC and north/west and 4 to 10 inches east of NYC.
December 29, 2012 Storm Archive
December 24 – Two Storms, Then Cold
December 25 – Final Storm Forecast
December 27 – Snow Expected For Saturday
December 28 – Saturday Snow Forecast
December 29 Storm Updates
Radar Archive – to be added soon
As the previous storm on December 26-28 exited the region into Nova Scotia and Newfoundland, another low pressure developed on Friday, 12/28, in the Gulf of Mexico region; this storm interestingly followed a track similar to the preceding storm, but was weaker and faster moving, with the primary low ending up over West Virginia with a minimum pressure of 1006 mb on Saturday morning, 12/29. Meanwhile, the coastal low pressure developed over South Carolina, and quickly intensified while tracking to the northeast and becoming the dominant low pressure, ending up near Long Island by Saturday evening with a minimum pressure of about 990 mb. The storm quickly exited the region overnight, reaching Nova Scotia on Sunday morning, 12/30, with a minimum pressure of near 978 mb.
Forecasting The Storm
This section will be added soon.
Radar image from 11:28 AM 12/29, from the National Weather Service, showing the initial round of snow over New York state and the developing coastal low over southern PA and NJ.
Precipitation spread into the region from the primary low pressure early on Saturday, 12/29, focusing over Pennsylvania. Light snow spread into western parts of the area towards 9-10 AM, although the rest of the area stayed dry through the morning hours as snow from the primary low remained mostly to the north and west, shifting into New York state and New England. The coastal low pressure, meanwhile, continued to develop, with an expanding area of precipitation affecting eastern Pennsylvania with heavy snow and coastal New Jersey with heavy rain.
Radar image from 4:58 PM 12/29, from the National Weather Service, showing the weakening primary low precipitation over NY state, and heavy snow from the coastal low over southeastern New England.
Precipitation from the fast moving coastal low pressure reached NYC around 12 PM, quickly spreading through the rest of the area by 1 PM. New York City and Long Island mainly fluctuated between rain and non-accumulating snow, while southern CT and the north/west suburbs saw moderate to heavy snow. As the coastal low pressure continued to intensify in the mid-late afternoon, a persistent area of lower snow rates set up over northeast NJ and the lower Hudson Valley in between the coastal and the dying primary low, where an area of lower totals of 1-3 inches was recorded. Precipitation inland continued to weaken as the coastal intensified, with a band of heavy snow setting up over southeastern New England towards 4-6 PM, with eastern Long Island gradually changing over to heavy snow as well. Snow mostly ended west of NYC by 6-7 PM while heavy snow continued over eastern Long Island/CT for another few hours.