Sunday, December 26, 2010

Dec 26, 2010 Blizzard Updates

Below, I will post brief updates throughout the day covering current observations, short term forecasts and any potential changes in the storm's forecast on the blizzard that will affect the area through Monday morning.


11:00 PM: The low pressure has significantly slowed down and is briefly stalling off the coast of Long Island, which will lead to heavy snowfall staying in the area for the next several hours. A very heavy snow band is moving into NE NJ right now, producing another round of 2-3"/hour snowfall rates. Temperatures are very cold, in the upper 10s to lower 20s across most of the area, which combined with wind gusts above 40 mph is leading to wind chills well into the single digits. An additional 4 to 8 inches of snow are possible tonight, with the heavy snow ending after 12-2 AM and light snow remaining until the morning hours.

The storm updates have ended for tonight. An update will be posted tomorrow morning reflecting the storm's forecasts, development, how it affected the area and the snow totals.

10:20 PM: The heaviest snow has ended for the area, however heavy snow is still ongoing and will not end until later tonight. Over the last 1-2 hours, places in the deformation band in northeastern New Jersey observed zero visibility, strong wind gusts near or even over 50 mph, and snowfall rates exceeding 2-3 inches per hour, with snow totals between 10-15 inches at this time. Waves of moderate to heavy snow bands took place in Long Island and S CT, with a steady light to moderate snow in NW NJ.

The low pressure is currently below 980 mb and is SE of Long Island, with very slow movement. The deformation band shifted slightly east and weakened a little, but is still capable of producing 2-3 inches per hour with strong wind gusts and zero visibility. Bands of moderate to heavy snow will continue to affect places east of this deformation band for the next several hours before starting to weaken after 12-2 AM, with an additional 4-8 inches of snow possible by the time that the storm ends. In NW NJ, light to moderate snow will continue and will slowly weaken over the next several hours.

8:40 PM: The worst of the blizzard is now taking place across the area, as widespread heavy snow is covering most of the area, visibility is near zero, wind gusts are near or over 50 mph, and wind chills are well into the single digits in some places. By the time that the storm is done, it will likely end up as one of the biggest snowstorms to affect NYC on record.

A heavy snow band with intensity between 35-40 dbz is stationary in western Bergen/eastern Passaic, eastern Morris, and the border between Rockland/Orange counties, which is producing very heavy snowfall with rates as high as 3 to 4 inches per hour, leading to these areas ending up with the biggest storm totals, likely between 18 and 24 inches of snow. Another heavy band is currently in Westchester county and in NYC, moving west while intensifying, producing rates of 2 to 3 inches per hour. With more bands of heavy snow forming offshore, heavy to occasionally moderate snow will continue falling across most of the area until late tonight, when the snow will start to weaken after 12-2 AM.

6:40 PM: Heavy snow bands continue to affect the NYC area at this time, and over the last 1/2 hour there were reports of thundersnow in the immediate NYC area, with even some cloud to ground strikes. The snow band's westward expansion was stopped around central NJ, so the western parts of the area will still see some heavy snow but with smaller amounts than the immediate NYC area. With temperatures in the lower to mid 20s across most of the area and strong wind gusts observed, with chills are very low, only in the single digits to lower 10s.

Widespread heavy snow bands are affecting Long Island and southern Connecticut, with these bands likely to reach the immediate NYC area around 8 PM after a small dry slot comes through briefly weakening the snow. Each snow band will be capable of producing snow rates between 2-4 inches per hour, strong wind gusts over 40 mph with blowing snow and near zero visibility, and more thundersnow can be expected.

5:30 PM: WARNING: A very heavy 35 dbz snow band is developing and expanding in western Long Island, near western Nassau county into eastern Queens, and is moving WNW to NW. This band will affect Queens and southern Westchester, and may extend into the rest of NYC and up to a line from Bergen county south into Staten Island if it does not weaken. This snow band is capable of producing strong wind gusts over 40 mph, snowfall rates up to 2-3 inches per hour, and thundersnow.

5:15 PM: The heavy snow band extending from Westchester county into NE NJ is producing near blizzard conditions, with heavy snow and strong winds. Snowfall accumulations are generally near or over 2-4 inches across most of the area, however will increase significantly tonight especially in the immediate NYC area as the worst of the storm is only starting.

Light to moderate snow continues to fall in NW NJ, with bands of moderate to heavy snow slowly moving in from the east. Developing snow bands offshore will bring moderate to heavy snow into most of Long Island where a dry slot brought much lighter snow mixing with some sleet, with the heaviest snow from western Long Island into NE New Jersey and SW Connecticut, where snowfall rates will increase up to 2-3" per hour at times, along with strong wind gusts and blizzard conditions.

4:00 PM: The heavy snow band is currently affecting northeastern New Jersey and SW CT, however it has weakened from earlier this afternoon, leading to lighter snow rates. While the snow is about to temporarily end in eastern Long Island as a dry slot comes through, bands of heavy snow are forming off the New Jersey coast as the low pressure, now near 988 mb and east of Delaware, continues to rapidly intensify while moving NNE up the coast, which is producing very heavy bands of snow in southern New Jersey and even some thundersnow.

Once the low pressure gets to New Jersey's latitude, these heavy snow bands will move north along with the storm, and will bring a much more widespread heavy snow focusing on the immediate NYC area, SW CT and western Long Island by this evening, and it is possible that as the storm slows down, they could also stall over the area for a while. These bands will be able to produce wind gusts of 40-50 mph or even higher, snow rates of 2 to 3 inches per hour, and thundersnow. Depending on where the heaviest snow bands end up, isolated areas could see amounts as high as 2 feet of snow.

2:35 PM: Over the last 3 hours, snow spread across the entire area and steadily intensified. A steady light to moderate snow is falling in the western parts of the area with a moderate, wind-blown snow across the rest of the area.

A heavy snow band is currently stretching from Cape May through central NJ into NYC and Long Island, and is slowly moving NW. This band is capable of producing heavy snowfall with rates up to 2-3 inches per hour possible and strong wind gusts over 40 mph. This band will continue to affect NYC while spreading into extreme SW CT, SE New York, and northeastern New Jersey. Heavy snow but not as heavy as the band in NYC will spread into NW NJ over the next several hours. Meanwhile, the snow will start to become lighter in Long Island.

12:00 PM: Light snow is already covering most of the area, with moderate snow falling from NYC and further east. Light accumulations are already being observed in places where snow is falling, as with low temperatures the snow can easily stick on most surfaces.

The snow is slowly expanding northwest, and around the next hour, light snow should start falling in the western parts of the area, but the heavier snow will not move in until later this afternoon. The snow may briefly weaken in the suburbs north and west of NYC in the short term, but between around 1-2 PM, potentially a little earlier or later, the heavier snow bands will start moving in from the south southeast. Long Island is seeing heavier snow moving in, and for the next several hours the snow will continue to gradually intensify.

10:45 AM: Light snow has started to fall across the eastern parts of the area, with some places reporting a dusting of snow already. The snow is expanding while moving NNE, and will continue to spread into southern Connecticut and steadily intensify over the next several hours with light accumulations expected. Further west, in the immediate NYC area, light snow will start to fall, but will not start to steadily intensify until after 12 PM. In the western parts of the area, light snow will only begin to fall after 12 PM, after the rest of the area starts to see snow. The snow will steadily intensify across the area through the early afternoon hours, with the heaviest snow until then in the eastern parts of the area.

We are currently seeing a 992 to 996 mb low pressure just off the coast of eastern North Carolina starting to become more negatively tilted. The latest NAM and GFS models are further east with the storm, bringing considerably smaller amounts to western New Jersey, however they are still having some issues, with the short term models further west with the storm. Updates through this afternoon will also focus on the location of the low pressure and whether it appears to follow the western or eastern solutions, though at this time observations seem to support a further west scenario, like the one described last night.


  1. I have to drive to work in this weather. I'm afraid to drive but have no choice.

  2. This comment has been removed by a blog administrator.


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