Jan 10, 2011: Major Snowstorm Tomorrow Night

***This post is from 2011. Please visit the MAIN PAGE to see the latest forecasts for January 2012.

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With mostly sunny skies, today was yet another chilly day, with high temperatures in the lower to mid 30s across most of the area. After two days of mainly clear skies, however, cloud cover will increase tonight as a storm approaches, bringing heavy snowfall to the area focusing on Long Island and Connecticut.


Storm Discussion: Long Island, Connecticut To Get Hit Hard


Precipitation associated with the storm last night that went through the South weakened, however that does not mean that the storm will fail to produce significant snowfall for the area. For reasons discussed in more details below, the storm will rapidly intensify once it moves up the coast, with the hardest hit areas expected to be in Long Island and Connecticut, where 15 to as much as 20-24 inches of snow are possible. New York City will be spared from the heaviest snowfall, however that does not mean that there won't be heavy snow, as at least 8 to 12 inches are still expected in NYC.


Storm Set Up: We are currently seeing a weak low pressure in the southeastern United States, that will start to move up the coast tonight into tomorrow. The primary low will be a weak low pressure moving through the Ohio Valley, bringing widespread light to moderate snowfall into the Mid Atlantic. The primary low pressure will then weaken as phasing takes place, and the coastal low will become the dominant storm.

The coastal low will then rapidly intensify tomorrow night tracking just east of Long Island, with intensifying precipitation, which may also lead to thundersnow in the eastern parts of the area. The low pressure will then stop intensifying on Wednesday while moving through southeastern Massachusetts.


Forecast For NYC Area: Light snow will begin to develop late tomorrow afternoon into the evening hours as light to moderate snow moves in from the south. The storm's appearance on the radar will be a weak light to moderate snow event in the afternoon, however the storm will rapidly intensify when it moves up the New Jersey coast, which will lead to intensifying snowfall. The western parts of the area will see the lightest snow totals out of the area, with moderate to heavy snow falling, and it is possible that some places in western New Jersey may not get into the heavy snow area. Heavy snow will fall in the central and eastern parts of the area overnight, with the heaviest snow over Long Island and Connecticut.

At the worst of the storm, which should be during early Wednesday morning, most of Long Island and Connecticut can expect snow rates between 2 and 3, potentially 4 inches per hour, strong winds gusting to near 40 mph creating near blizzard conditions at times, and thundersnow cannot be ruled out from the rapidly intensifying storm. The immediate NYC area will still see significant impacts but not as bad as locations further east, with snowfall rates up to 1 and 2 inches per hour and gusty winds leading to near zero visiblity at times with blowing snow. As the storm moves to the northeast of the area, moderate to locally heavy snow will continue through the morning hours, and should gradually weaken. By the afternoon, most of the area will be dry other than some snow showers, especially further east.

When the storm is over, at least 5 to 9 inches of snow are expected in the western parts of the area, 8 to 12 inches of snow in the immediate NYC area, and widespread 12+ inch amounts in Long Island and southern Connecticut. It appears that the heaviest snowfall may extend from central LI into south central CT and further northeast, where amounts over 15 inches of snow are possible, and depending on the intensity of the snowfall, amounts locally as high as 2 feet of snow are possible in these areas. Note that there is still some slight uncertainty with the totals, and they may change a little with the final forecast tomorrow in the late afternoon.


Forecast For The Region: As previously stated, the storm will begin as a light to moderate snow event in the Mid Atlantic, with snowfall amounts less than 5 inches. The heavier snow totals will be near Delaware and the mountains of West Virginia, with the lightest totals near western Virginia. Note that areas of over 5 inches of snow are expected also in western Pennsylvania and potentially other parts of New York State which were not included in the map.

As the storm moves further northeast, the snow should intensify, with widespread heavy snowfall from eastern New Jersey into New York City, Long Island and southern New England. The heaviest snow will fall in Long Island and Connecticut, potentially extending into parts of Rhode Island and Massachusetts, where over 15 inches of snow are possible.

The main uncertainty areas at this time include the western extension on the 10-15 inch zone, which may be extended slightly west to cover NE New Jersey, or slightly east to stay a bit east of New York City, and its northern extent, which may be pushed north of where I have it to cover east central NY into southern Maine. There is also uncertainty on the northern end of the 5-10 inch zone.

Once again, this is a dangerous storm, and should not be taken lightly. Stay tuned for the final forecast on this storm tomorrow afternoon, and a few storm updates tomorrow night and on Wednesday morning.


Longer Range: The longer range will be discussed in a little more details tomorrow, though at this time the coldest temperatures of the winter so far are expected between Thursday and Saturday, with high temperatures in the 20s for almost all of the area, and low temperatures could reach the single digits in the western parts of the area on Friday night.