Dec 6, 2013 Storm Updates

Occasional updates will be posted below on the rain, snow and sleet event affecting the region tonight. The next full forecast update on Sunday night’s storm will be posted on Saturday morning.


Final storm precipitation totals in NYC:

Central Park – 0.87″
LaGuardia – 0.86″
JFK Airport – 0.74″


Blog Updates: (Regional radar from the Pennsylvania State University e-Wall)

 

11:00 PM: Snow Outlook Lowered

nerad252Over the last few hours, the mixing line continued to gradually shift southeast, with parts of Sussex and Orange counties reporting mixing with sleet. Reports across the region primarily in Pennsylvania and New York, however, suggest that snowfall amounts are lower than initially modeled, and precipitation is quickly drying up over western Pennsylvania, which would lead to an earlier ending of the steady precipitation than previously forecast, and thus lower snow totals, with at least up to 1″ or locally higher in far NW NJ and interior SE NY.

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

 

8:30 PM: Heavy Rain North of NYC

nerad25Since the last update, widespread moderate rain spread into the area, falling heavily at times north of NYC. Colder air continues to slowly spread southeast, with locations just north of Orange and Putnam counties reporting snow and sleet. Current rain totals in NYC range from 0.33″ in JFK to 0.47″ in LaGuardia.

Temperatures will continue to slowly fall tonight as the mixing line gradually shifts southeast, with sleet expected to fall in interior NW NJ and Orange county by 11 PM, when precipitation will begin to change to snow in the aforementioned locations while gradually extending southeast from there until reaching north central NJ, the rest of SE NY and southern CT away from the coast before the storm ends. Forecast totals remain unchanged at this time.

 

5:30 PM: Rain Entering Area

2200Last night, an area of light to moderate rain affected the area, with rain totals so far generally below 1/4 inch. A temporary break in the rain was observed behind the first wave, while a second and more intense wave of precipitation is moving along the frontal boundary, currently located south of New Jersey, and entering the area with steady rain expected to develop by 7 PM.

This wave has been complicated to forecast, as while it had initially appeared any snow accumulations over 1-2″ would remain decently north of the area, observations this morning suggested that the model guidance over the last 2 days was too far north, and today’s runs have gradually adjusted towards a colder and further south precipitation shield, with the heavy snow axis with 5-10 inches of snow over central PA into the central Hudson Valley, as opposed to yesterday’s indications over northern PA into central NY state.

Tonight’s Forecast: As steady moderate rain spreads into the area tonight, temperatures will gradually cool down. Initially, warm mid level temperatures will lead to sleet mixing at times with the rain towards interior Sussex and Orange counties through 11 PM, when the mixing line will gradually shift southeast as mid level temperatures fall slightly below freezing. A changeover to snow, mixing with sleet initially, is expected over Sussex, Orange and Putnam counties by 12-1 AM, which could be heavy at times over northern Orange county. The mixing line will gradually shift southeast, with north central NJ and Rockland county mixing with sleet and possibly snow towards 1-2 AM. Precipitation is expected to end around 4 AM from west to east, with sleet likely to mix in as far as northeast NJ and CT away from the coast.

The current accumulation forecast is for 1 to 3 inches of snow and sleet in NW NJ and Orange/Putnam counties in NY, locally up to 4 inches in Orange county, and less than an inch of snow in north central/far northeast NJ into the rest of SE NY and southern CT away from the coast. For the rest of the area, at least 1/2 to 1 inch of rain is expected. As the southern shift has been a short range development, the system will continue to be monitored over the next few hours for any changes in the forecast.

Sunday Night Update: As the previous forecast discussion from Wednesday noted, an uncertainty in the outlook for Sunday night was the precipitation amounts, as the potential was there for an initial wave of precipitation to bring moderate snowfall to Maryland and southern Pennsylvania, which then slides south of the area as precipitation intensifies again nearby and to the north, but too late to support widespread moderate snow accumulations, as little precipitation falls when temperature profiles are the most supportive of snow. This trend has been prevalent in some of the model guidance over the last few days, especially the GFS.

The latest forecast is for snow showers to develop after 7-9 PM; with easterly winds expected, a quick changeover to rain is anticipated for NYC and Long Island. Further inland, light snow will continue through at least 2-4 AM, with a gradual changeover to sleet and then rain as precipitation begins to intensify. The most significant freezing rain totals are expected west and southwest of the area, with a significant ice storm possible over western Virginia into Maryland and Pennsylvania, although several hours of freezing rain are likely over NW NJ and interior SE NY as well before changing to rain around 7 AM, with ice accumulations up to or possibly over 0.10 inch possible. More information will be posted with Saturday morning’s update.

3 thoughts on “Dec 6, 2013 Storm Updates

    • NYC Area Weather Post authorReply

      NYC is not expected to see frozen precipitation tonight; if any was to fall, however, which is unlikely based on latest indications, it would be in the form of sleet and would likely fail to accumulate.

  1. Eduardo Berroa Reply

    Pleasant Evening…

    This year actually sucks due to the lackluster series of severe storms for NYC Boroughs and however, NYC Borough gotten quite impressive thunderstorms in the mid-Spring, Summer and late Summer through early Autumn.

    Furthermore, Can any chances exist for the potential probability of severe storms, especially semi-rotating thunderstorms and unprecedented supercell thunderstorms may become actively frequent for NYC Borough in 2014? Hail to 1.00 inch or more than 1.75 inch, thunderstorm wind to 60-70 mph, perhaps some chances of an limited microburst potential and some chances for weak, short-lived tornadoes or EF-2, would the events become potential threats for NYC Boroughs during severe thunderstorms?

    Will NYC Borough may experience an outbreak of severe storms and tornadoes?

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