December 2013 Archives - Page 5 of 7 - New York Metro Weather

Live Blog: First winter storm of the season begins in NYC

December 10, 2013/0 Comments/by John Homenuk

11:30am Update: There is a bit of a lull right now as the initial band has moved to our east, and lots of precipitation as expected missed us offshore.

But now that the system is interacting with a mid-level disturbance to our west, snow has blossomed again in E PA, and especially in SW Jersey near Philly, and head NE. The core of that heavy band may just miss NYC, but the NYC area will still see some more moderate snow within the hour and perhaps another inch or so of accumulation.

That band will probably head from I-95 and just south and east, hitting most of Middlesex county, probably clip Union county, hit Monmouth county, and then head towards Long Island, where probably another 1-2″ will fall.

There has been some melting during the lull in the action, as surface temperatures have been hovering right around freezing, and rose just above freezing during the lull in some spots. -DS

10:00am Update: Ingredients continue to lineup for heavy bands of snow in the region, particularly around the I-95 corridor or just south of it.

SPC mesoanalysis shows favorable ingredients for snowfall banding located on the I-95 corridor, or just south of it.

The image above shows a mesoscale snowfall banding parameter called EPVg. We won’t get overly technical, but it’s basically an index that tells us if we can expect slantwise convection, which is a much stronger type of lifting mechanism for snow bands than just straight convection. The values are more impressive as one heads southeastward, so lots of precipitation will blossom in S NJ and head just offshore, but there is certainly enough of this for heavy bands to traverse I-95, and especially southeast of there, particularly from 10:00am through noon. 1-2″ of snow per-hour can be expected in some of these bands, with around 1/2″ of snow per hour outside of the bands.

The storm is moving quite quickly, so even in the heaviest banding, 6″ will probably not be exceeded. A general 3-5″ snowfall is still expected, with maybe a tad less further NW of I-95 — though even there, slightly higher snow to liquid ratios due to colder temperatures may make up for the lack of precipitation. -DS

9:10am Update: Took this photo about 10 minutes ago in Rockville Centre, NY — shows that even along the coast, the roads became white right away. Be safe out there! -DS

9:00am Update: Heaviest band of snow has formed in a SW to NE zone from Trenton, through Middlesex, NW Monmouth, Staten Island, NYC, and western Long Island, where 1-2″ of snow per hour can be expected. The ideal snow growth on the models has been realized, as large, fluffy dendrites are falling.

I’m in SW Nassau County, and even here, temperatures quickly fell once the snow started, and it is now accumulating everywhere. Do not let the initial slightly above freezing temperatures fool you if you are along the coast — temperatures fall very quickly once the heavy snow arrives.

Give yourself some extra time on this morning commute. -DS

8:50am Update: Banding and areas of heavy snow have continued to develop and expand some as anticipated. A bit of warmer boundary layer (near surface) temperatures near the immediate coast will melt the initial snow (may even be a rain/snow mix) upon contact, but as snow rates increase the accumulations should begin. Not many other changes otherwise since the last update. Heavy snow is expected to continue, especially across much of New Jersey into New York City, over the next few hours.

Snowfall total forecasts also remain unchanged (you can view it in our previous article). We are expecting generally 2-5″ throughout the majority of the area (lesser end north, higher end south) with isolated higher totals in areas that sit under banding for prolonged periods of time.

Regional radar imagery as of 8:50am showing blossoming area of moderate to heavy snow throughout the area.

Winter Storm Warnings issued as snowstorm approaches

December 9, 2013/0 Comments/by John Homenuk

The National Weather Service issued Winter Storm Warnings and Winter Weather Advisories for the entire area on Monday evening, in advance of a light to moderate snowstorm which is expected to impact the area on Tuesday. The Winter Storm Warnings, in effect through 6pm on Tuesday evening, cover much of Southwestern and Central New Jersey as well as the major cities of Philadelphia and Trenton. Elsewhere, Winter Weather Advisories are in effect for the rest of New Jersey, New York City, Southwest Connecticut and Southeast New York. The advisories currently do not include Eastern Long Island or interior New York State.

The watches and advisories were issued in advance of a forecast snowstorm, which will approach the area on Tuesday. A mid level disturbance sliding eastward, and a frontal boundary providing the focal point for enhanced lift and development of precipitation, will set the stage for the event. A band of moderate to heavy snow is forecast to develop by late Tuesday morning, but forecast models have been struggling with the exact placement of the band. Regardless of that bands eventual position, 1-3″ of snow seems increasingly likely throughout the majority of the region. But the heavy snow band, and enhanced forcing within it, provides extra intrigue for potential higher amounts. We break down Tuesday snowfall event with timing, snowfall totals, and hazards information below.

Storm total snowfall forecast (left) and NWS Watches, Warnings and Advisories (right).

Wintry weather continues; More snowfall Tuesday

December 9, 2013/0 Comments/by John Homenuk

A wintry mess was the most fitting way to describe the morning commute on Monday as snow, sleet, and freezing rain provided a myriad of issues with travel. Traffic, accidents, and delays on the area roads and with local mass transit likely lead to a headache for most — if you were able to get in to work or class without an issue, consider yourself lucky. The ice and wintry precipitation caused closures of schools and businesses over the interior, but coastal and urban locations including the NYC Metro were much warmer by morning — allowing for a more wet commute than white.

The disturbance moving through the area will shift northeastward on Monday, ending with scattered showers throughout the area. Colder air will begin to filter in rapidly behind the system on Monday Night. As an early warning, you’ll want to be extra careful on the evening commute and during any overnight travel as well. The falling temperatures could lead to re-freezing of any water on roadways and other surfaces.

But our problems don’t end there. Forecast models have come into better agreement on another disturbance which will shift northeast through the area on Tuesday. Much colder air will have moved into the area both aloft and at the surface, so this storm system looks to provide less difficulties in forecasting precipitation type: Mainly snow. Bands of snow will develop by late morning into afternoon on Tuesday, accumulating initially across the interior ( a little slower to do so on the coast and in the city with warmer ground and surfaces).

Storm Total Snowfall forecast through Tuesday evening. Please note that forecasts are subject to change prior to the event.

PM Update: Wintry weather continues

December 8, 2013/0 Comments/by John Homenuk

Several inches of snow fell earlier today across parts of Southeast Pennsylvania, into Southern and Central New Jersey as a mid level disturbance triggered precipitation — which fell along a gradient between warm air advection to the south, and cold and dry air to the north. The combination lead to an enhanced frontogenesis event, with bands of heavy snow lasting several hours during the day on Sunday. Snowfall totals within warning criteria (over 6″) fell in parts of Delaware, Pennsylvania and New Jersey by the time the snow let up. Farther north, closer to Northern New Jersey and New York City, the drier air won the battle. A half inch or so of snowfall fell before precipitation entered a lull on Sunday evening.

Which is where we pick up — with a break in precipitation occurring throughout the area this Sunday evening. Warm air advection, however, is ready to come back for more — with additional precipitation expected to develop by later tonight into Monday morning. As the warm air advection helps to drive precipitation farther north, it will also warm the mid levels of the atmosphere — allowing for a gradual changeover in precipitation type throughout the area. Winds turning from northeast to southeast by later tonight will also warm the surface, especially along the coast. Although another period of snow is likely, it should be somewhat brief in the city and near the shore before transitioning to sleet and plain rain. Farther inland, a period of frozen precipitation is expected as well before a changeover. It is the far northern suburbs which may still experience a more prolonged period of snow and sleet — with the potential for 1-3″ of snow and sleet by Monday morning.

NAM model showing mixed precipitation accumulations through Monday morning — freezing rain, sleet, snow and rain.

The National Weather Service continues Winter Weather Advisories throughout much of the area through 3:00am (New York City and coastal areas) and 6:00 am (Interior suburbs of New Jersey and New York). Travel this evening will be slick, with areas of ice and snow on all roads. This will be less of an issue near the coast and in the 5 Boros, especially with the lull in precipitation allowing for crews to treat the roads. Inland, colder temperatures and another period of wintry precipitation suggest that the morning commute may be messy.

National Weather Service watches, warnings and advisories valid from Sunday Night into Monday morning

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