Dec 29, 2012 Storm Updates

Updates will be posted on the rain and snow event currently affecting the region. A few detailed updates will be posted in the bottom of this post, with most updates from Twitter.


Blog Updates:

3:55 PM: Since the last update, the coastal low affected the area, with moderate accumulations observed in NW parts of the area. Towards NYC and NE NJ, however, this is busting on the low side, with rain in NYC resulting in barely any accumulations, while a persistent dry slot in NE NJ just west of the banding with the coastal low prevented locations from picking up much more than an inch. Long Island has seen rain so far, although a changeover to snow is expected as the coastal low intensifies, with heavy snow expected for some areas.

With the latest observations, the totals have been again revised. For NW NJ and SE NY, 2 to 5 inches are still expected. In NE NJ, 1-3 inches are expected, with less than 2 inches in NYC and western Long Island. Higher totals are expected in eastern Long Island due to heavy precipitation from the coastal low tonight with parts of the island picking up 2-4 inches, with the highest totals in the area in eastern and central CT, where at least 4 to 8 inches of snow are expected, with locally higher totals above 8 inches towards eastern CT.

12:10 PM: Since the last update, the coastal low has continued to intensify, and is currently a 1002 mb low near eastern North Carolina moving NNE. Precipitation associated with the coastal low continues to expand and intensify, and moderate to heavy snow is moving into the area, mixing with rain in parts of Long Island. Heavy snow rates are expected up to 1/2 to 1 inch per hour especially west and north of NYC for the main part until the storm ends.

Forecast accumulations have been slightly raised to 1-3 inches in Long Island, 2-4 inches in NYC, 3-5 inches in NE NJ and SE NY, and 4 to 7 inches in southern CT. Locally higher totals may be possible.


10:30 AM: The snow from this storm has been affecting Pennsylvania and New York throughout the morning, although most of the area has been dry so far. Last night’s update mentioned the potential for a drier area to set up near the Interstate 95 corridor southwest of NYC in between the interior snowfall and the developing coastal low, which is what is currently happening, only that the dry conditions are reaching NYC and extending into southeastern New York. Precipitation from the developing coastal low is currently intensifying over Washington DC, and will reach the area late this morning through the afternoon hours.

Currently, temperatures are currently cold enough to support snow across most of the area, with 925mb temperatures ranging from 0C in eastern LI to -4C in NW NJ, and 850mb temps near -3C to -5C across the area. A southeast wind persists at 925mb, however, with the low still near western Pennsylvania, and 925mb temperatures will continue to rise. With that said, some of the models were already too warm for this morning, showing NYC and Long Island in the upper 30s when temperatures are only near 33-34 degrees for most, and may be overdoing the warmth at 925mb and thus the northern extent of the rain/snow line as well. The current forecast for today is still for plain snow north and west of NYC, perhaps mixing with rain at times towards Newark; snow occasionally mixing with rain in NYC and western LI; and mostly rain for eastern and coastal Long Island.

At this time, my thoughts on snow accumulations have not changed, although locally higher totals are expected across the area, especially in Connecticut. Below is an updated version of my regional snow map posted yesterday on Twitter:

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