January 11-12, 2011 Storm Updates

Below, storm updates will be posted on the major winter storm that will affect the area between Tuesday, January 11, through Wednesday, January 12.

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11:00 PM: As the coastal low is quickly deepening, already near 1005 mb south of New Jersey, and is moving NNE, precipitation continues to intensify, and we are currently seeing a large area of moderate to heavy snowfall in New Jersey moving NNE. The heaviest bands are off the coast of SE New Jersey, where thunder has been reported, and are moving NNE. These bands will weaken once they reach the area, but will affect NYC and further east with heavier snowfall.

The low pressure is currently moving NNE, and at its current rate may pass over eastern Long Island, which is west of what the NAM and even the RUC models have to some extent. Later tonight, the storm will continue to produce heavy snowfall for places including and east of NYC through the overnight hours, while lighter snow will fall over western New Jersey. The heaviest snowfall will focus on Long Island and Connecticut. The snow will start to end from south to north by the morning hours.

This is the final storm update for tonight. The next update will be posted tomorrow morning.


10:20 PM: As the coastal low pressure continues to take over, precipitation is now moving in from the south, not from the west like it did before. Heavy precipitation is developing offshore and is moving north to NNE, with the first band of heavy precipitation about to move into central and eastern Long Island. Mixed precipitation may fall with this band.

Further west, moderate to locally heavy snow will continue to fall in the immediate NYC area with low visibilities, and lighter snow will fall further west. The heavier bands are currently developing just off the New Jersey coast and moving NNE, which will likely bring the heavier snowfall for tonight from NYC and further east/northeast.


9:35 PM: We are currently seeing a 1011 mb low pressure off the coast of eastern Virginia, with another 1011 mb low in NE Ohio. The low pressure off the coast will become the main low pressure, and will continue to steadily intensify over the next few hours. Heavier snow is currently moving into the central and western parts of the area from the southwest, which may mix with sleet or rain at times near the coast, and snow will begin falling in the eastern parts of the area within the next hour or two.

Last hour, I updated the final storm forecast, raising the snow totals for the central parts of the area. As the coastal low is developing, it has been observed that the low is tracking closer to the coast than most models suggested, and is also a bit stronger than some models. While it is expected to turn NNE later tonight, it may track far west enough to bring the heavier snowfall as far west as New York City and potentially extreme northeastern New Jersey. As a result, I raised snow totals slightly, going with 8 to 12 inches in NE NJ and 9 to 14 inches in NYC. In areas where the western end of the deformation band sets up, which appear to be in western/central Long Island and western/central Connecticut, snow totals of near or over 15 inches are expected once the storm ends, with amounts locally as high as 2 feet of snow.

Note that there is still some uncertainty with these amounts, and it is possible that the storm stays further east again with less snow for NYC and further west. Stay tuned for updates that will be posted over the next hour and a half.