January 16, 2013 Storm Summary

January 16, 2013 Snowstorm

A weak low pressure developed along a stalled frontal boundary, producing the only widespread snow event of January 2013 in the NYC area. A mix of snow, sleet and rain fell in NYC and further south/east with less than an inch, with moderate snow to the north and west of NYC with 2 to 4 inches of snow. The storm was the most significant of the 3 low pressures that affected the region during this time frame.

 

 

 


January 16, 2013 Storm Archive

January 13 – Light Rain/Snow Possible Tues-Weds
January 14 – Noon Update
January 14 – Rain/Snow Weds; Long Range Update
January 15 – Snow, Rain, Sleet, Ice Tonight
January 15 Storm Updates

 


Storm History

NAM at hour 6 showing the approximate position and precipitation shield of the 2nd storm on 1/16 6z (1 AM) – image from NCEP Model Analyses and Guidance

On January 11, a strong low pressure tracked through the Midwest, bringing a frontal boundary slowly to the east. A highly amplified mid-upper level flow was in place with strong ridging in the NE Pacific ocean and the eastern US and a strong trough in the western US, resulting in a persistent western trough/eastern ridge pattern that was slow to push eastward. Two waves of low pressure moved through the Ohio Valley on January 13, pushing the cold front into the East Coast, but the progress of the front was stalled with persistent ridging off the eastern US coast.

As the frontal system stalled just off the coast, two waves of low pressures initially rode up the stalled boundary; the first was on Monday through Tuesday, January 14-15. This round produced moderate to heavy rain south of NYC with 1/4 to 1/2 inch, locally higher, and light rain, mixed with sleet, to the north of NYC. There was no well defined surface low pressure associated with this wave, and precipitation weakened once moving east of the NYC area. A stronger and further north wave of low pressure developed on Tuesday night into Wednesday, January 15-16, producing snow in the Northeast and rain/sleet in the Mid Atlantic. There was a somewhat defined surface low pressure, starting near SE Virginia early on 1/16 with a minimum pressure of 1018 mb, tracking NE towards Cape Cod and SE Nova Scotia while deepening to 1006 mb. A stronger shortwave tracked through the Southeast on the 17th, with a stronger coastal low developing near the Carolinas, deepening to 1006 mb while quickly tracking off the coast and finally pushing the frontal boundary offshore.

 


Forecasting The Storm

The three storms were not forecast well in advance, especially from the medium range. The medium range model guidance underestimated the intensity of ridging in the southeast US, keeping the frontal boundary stuck well offshore with a few isolated rain/snow showers reaching the Northeast. For the 2nd wave of low pressure on January 16 producing widespread snow in the Northeast, the models initially showed rain/snow affecting the area in the medium range prior to 1/10, but then trended weaker with the ridging and kept the low offshore, not showing more widespread impacts with the 1/11 and 1/12 runs. Most models showed either light rain/snow affecting the NYC area or a suppressed wave of low pressure to the south, aside from a CMC run on 1/11 which showed a major I-95 snowstorm. The ECMWF, which is typically considered to be a reliable model and was especially accurate with hurricane Sandy, was in fact one of the worst performing models for this storm, consistently showing the storm much more south and weaker than reality, and was among the southern end of the model guidance.

The model guidance only began to reach a new agreement on a widespread storm in the region with the 1/14 0z runs, only 2 days before the storm, with the model guidance trending more amplified with ridging in the East with each run, thus leading to a sudden trend north with the low pressure and precipitation shield. The GFS and UKMET were in the northern end of the model guidance, showing rain/mix in NYC and widespread moderate snow in the interior Northeast, while the ECM, NAM and CMC were in the southern end of the model guidance, showing 2-4 inches of snow across the NYC area. While the GFS was closer to reality with the precipitation shield than the ECM, which was too far south and too cold, the GFS exaggerated warmth in the mid levels and the surface as well, showing even northern parts of the area changing over to a sustained period of rain, when in reality those areas stayed with mostly snow.

 


Storm Impact in the Northeast

Regional radar image from 10:58 PM 1/15,  from the National Weather Service, showing the 2nd wave of low pressure. Rain fell south of NYC, with a rain/snow/sleet mix elsewhere.

The first wave of low pressure affected the region on the night of the 14th into the morning of the 15th, on Tuesday morning. Moderate to locally heavy rain fell from NYC and further south, with the northern edge of the storm near NW NJ into central CT where sleet and some snow mixed with the rain with minimal accumulations. There was no well defined surface low pressure, and most of the rain weakened after exiting the area.

The second wave of low pressure, radar image shown to the left, affected the region between Tuesday night into Wednesday afternoon, January 16. Moderate precipitation spread on Tuesday night into Pennsylvania and New Jersey, with the former seeing light snow and sleet. Through the overnight hours into Wednesday morning, snow spread into the rest of the Northeast, with the heaviest snow falling from southern NY state into southern Maine. In the NYC area, rain and sleet fell from NYC and further south/east with little to no accumulations, while the immediate north and west suburbs observed a mix of sleet and freezing rain, mixing with snow at times, with up to 1-2 inches. Interior suburbs and southern CT observed mostly snow, mixing with light rain at the end of the storm on Wednesday morning, with at least 2 to 5 inches of snow.

The third wave of low pressure affected the region between Thursday afternoon and evening, January 17. Widespread precipitation fell south of Washington DC and Delaware, with moderate to heavy snow affecting parts of Virgina. Precipitation from this wave was further south, however, failing to spread into the NYC area, with the low pressure intensifying and moving offshore overnight, dragging the frontal boundary to the east as well.

 


Storm Snow Totals

While the first wave produced little snow well southwest of the area, the second wave was the most widespread snowstorm of the month in the region. Snow totals of 3 to 5 inches were observed from central PA into southeastern NY, Massachusetts and southern Maine. The NYC area was in the southern end of the frozen precipitation of the storm; NYC, Long Island and New Jersey south of I-80 recorded rain/sleet with little to no accumulations, the immediate north/west suburbs of NYC observed up to 1-2 inches of snow, sleet and freezing rain, and interior parts of the area and southern CT recorded 2 to 5 inches of snow. The highest snow total in the area was 4.5″ in Hamptonburgh, NY in Orange county. The third wave of low pressure produced light to moderate snow accumulations in the southern half of Virginia, especially in the higher elevations.

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:
4.2″ – West Milford, NJ (Passaic)
3.8″ – Oakland, NJ (Bergen)
0.9″ – Cedar Grove, NJ (Essex)
0.2″ – Hoboken, NJ (Hudson)

Southeast NY:
4.5″ – Hamptonburgh, NY (Orange)
4.3″ – Somers, NY (Westchester)
4.2″ – Stony Point, NY (Rockland)
4.0″ – Mahopac, NY (Putnam)

New York City:
0.1″ – Midwood, NY (Brooklyn)
0.1″ – LaGuardia, NY (Queens)
T – Central Park (Manhattan)

Long Island and South CT:
4.3″ – Southbury, CT (New Haven)
4.2″ – Lisbon, CT (New London)
4.0″ – Shelton, CT (Fairfield)
2.0″ – Old Saybrook, CT (Middlesex)
0.3″ – Mount Sinai, NY (Suffolk)
0.2″ – Lynbrook, NY (Nassau)

 

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