Dec 7, 2011 Storm Updates

Below, updates will be posted on the storm currently affecting the region.


10:30 PM: Heavy Rain Continues; Snow To Fall Soon Inland

The heavier rain from the Mid Atlantic has moved into the area, with widespread moderate to heavy rain now falling from NYC and further north/west. Although Long Island is seeing mostly dry conditions, the rain will begin to move east within the next 2-3 hours as the low pressure moves towards eastern Long Island. Heavy rain will continue to affect the immediate NYC area over the next few hours, while the interior parts of the area begin to mix with snow after 12 AM. With the storm quickly moving out of the area, most of the rain will move out by 3 AM, with leftover snow showers inland and rain/snow showers in the immediate NYC area lasting until at least 4 AM. With the storm moving out, strong yet brief windy conditions will develop, with widespread 30-40 mph gusts, locally reaching 45 mph, expected across the area between 2-8 AM Thursday.

No update will be posted to the pages tonight. The 5-day forecast and winter pages will be updated on Thursday afternoon, with a discussion on the forecast to be posted in the evening.

Main forecast highlight: Very cold temperatures are expected for Saturday night into Sunday as a strong yet brief trough moves over the region. On Saturday night, the entire area is expected to drop into the 20s, including NYC where lows will be in the upper 20s to lower 30s. Widespread low to mid 20s are expected in NE NJ, Rockland/Westchester counties, southern CT and parts of Long Island, with temperatures dropping into the upper 10s for parts of NW NJ and Orange county. Sunday will bring widespread highs in the upper 30s across the area with a few lower 40s expected in the immediate NYC area.


7:30 PM: Heavy Rain To Soon Move In

As a wave of low pressure developed near the southern Mid Atlantic today, occasional periods of rain affected the area throughout the day, become more steady by the afternoon and evening hours. Since Tuesday, the storm total so far is between 1 and 1.5 inch inland, 1/2 to 1 inch in the immediate NYC area, and between 3/4 and 1 inch across most of Long Island and southern Connecticut.
The wave of low pressure is currently located close to southern Delaware, and is quickly moving northeast. The low pressure will continue to rapidly intensify and cosolidate itself tonight, which will bring the heavy thunderstorms currently in the southern Mid Atlantic further northeast. Although severe thunderstorms will not affect the immediate NYC area as the air mass is more stable than the air mass in the Mid Atlantic, heavy rain is expected to affect the immediate NYC area and southern CT, later on Long Island, this evening, likely towards 10 PM to 1 AM. In the interior parts of the area, snow will begin mixing with the rain after at least 12 AM, with the rain and snow mix falling heavy at times until 2 AM before becoming lighter, ending by 4 AM.
In the immediate NYC area, rain will continue to fall until at least 2-3 AM, but as cold air quickly moves in behind the low pressure, with the southern end of the deformation band moving near NYC, a 1-2 hour period of light snow is possible in the north and west suburbs of NYC, with possibly a few snowflakes in the city itself as the storm ends. Although the snow will not accumulate in the immediate NYC area, it may bring the snow totals this month to a trace. The storm is expected to end across the entire area by 3-4 AM, with clearing skies for Thursday morning. In addition, as the storm moves out, a few hours of windy conditions are expected between at least 2 and 8 AM, with widespread wind gusts between 30-40 mph possible.

This storm will not end up as wet as originally expected with the low pressure slightly further west than expected and the faster timing of the storm, although additional moderate to heavy rain will continue tonight. Including the totals through this evening, the final storm total rainfall is expected to end up between 1.5 and 2 inches inland and 1 to 2 inches across the rest of the area. Rain amounts may be locally higher north/west of NYC and in parts of Long Island. For the interior parts of the area, light snow accumulations are expected, with at least 1 to 4 inches of snow. The highest accumulations will end up near far NW Sussex county and Orange county in NY.

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