Feb 8-9, 2013 Storm Updates

Storm updates will be posted below on the major snow and blizzard event currently affecting the region. Live storm updates will be posted on Twitter, with occasional detailed updates and any revisions to the forecast in the bottom of this post. Last night's forecast discussion for the storm can be found here.

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Live storm updates will be posted on Twitter occasionally throughout the day.

Twitter updates from February 8-9, 2013 are archived in the NYC Area Weather twitter page.

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Blog Updates:

2:08 AM Update: The band of snow is located over western Bergen into Essex counties, and is moving southeast. Snow rates over 3 inches per hour have been reported with very low visibility; the band will last for less than an hour, which should still add totals of at least 1 or more inch for locations under this band. This band marks the end of the snow; behind it, snow will gradually taper off.



1:35 AM Update: Narrow but heavy snow band is currently located over western Passaic and SE Orange counties, extending down to eastern Morris county and Philadelphia. This band is moving southeast, and will affect NE NJ and NYC within the next 1/2 to 3/4 hour. Very heavy snow rates can be expected over 2 inches per hour along with lowered visibility.

1:15 AM: Over the last 30 minutes, additional developments have taken place. The bands over Connecticut drifted west, now over Bridgeport, CT, and have actually intensified, with a 35+dbz band of heavy snow nearly stalled overhead, connecting into western Suffolk county. The snow will weaken within a few hours, but with the bands stalled over the same locations for the last few hours, widespread totals above 24 inches are expected in this axis.

Another update to make note of is the thin line of heavy snow bands over NW NJ. A heavy snow band is currently located near Orange county, NY and is moving southeast. This band may weaken as it approaches NYC but is likely to result in heavier snow rates over Passaic and western Bergen counties over the next 1/2 to 1 hour. Snow will gradually begin to end behind this line.

Unless unexpected changes occur, this will be the last storm update for tonight. A brief summary update will be posted in the morning, with the next forecast discussion to be posted tomorrow night or on Sunday morning regarding the upcoming pattern through the rest of the month with the possibility for more snow events.

12:40 AM: As of 12 AM, the low pressure was located slightly northeast of the previous 10 PM location, south/SSE of Cape Cod and east of central NJ. The minimum pressure is just under 980 mb with the low slowly moving to the northeast.

Moderate to locally heavy snow continues over northern NJ and SE NY as the back end of the storm approaches northwestern NJ and interior SE NY in the form of heavy snow bands drifting SSE. These bands will result in temporary heavy snow rates, lower visibility and stronger wind gusts. West of NYC, the storm is expected to end towards 4-7 AM, with final snow totals between 9 and 16 inches of snow, locally higher in some spots and lower in others.

The highlight of the storm is over Connecticut into portions of Suffolk county in Long Island, where heavy snow continues to fall with the highest totals in the area expected. A heavy band of snow remains stalled over the New Haven-Bridgeport to Hartford, CT corridor, where totals as high as 24-34 inches are expected. Elsewhere, moderate to heavy snow continues to fall, with snow continuing through the morning hours before ending.

11:25 PM: As of 10 PM, the low pressure was located south of Cape Cod and east of central New Jersey. Minimum pressure has been steady at approximately 982 mb for the last 2 hours. The low continues to track to the northeast, although it has significantly slowed down.

After the extreme heavy snow bands weakened in Long Island and Connecticut, the heavy snow bands extended west through Long Island, and are currently stalled over New York City and western Long Island, clipping portions of northeastern NJ. These bands are producing heavy snow with low visibilities and snow rates of up to 1-2 inches per hour. Moderate to locally heavy snow otherwise continues across northern NJ and SE NY as well as southeastern CT.

The heaviest snow is currently located near the New Haven-Bridgeport to Hartford corridor in Connecticut with a band of 30-35dbz snow stalled. These locations will end up with the highest snow totals in the area when adding the earlier very heavy snow, with totals as high as 24-34 inches in this axis. Otherwise, most of southern Connecticut is expected to end up with 16 to 26 inches of snow, with totals as usual locally higher or lower. Suffolk county in Long Island, affected by heavy snow earlier today, is expected to end up with similar totals to the rest of southern CT, with the rest of Long Island generally from 7 to 16 inches, locally lower/higher. Northern NJ and SE NY are expected to end up with 9 to 16 inches of snow, locally higher, with 6 to 12 inches in NYC.

9:20 PM: As of 8 PM, the low pressure is currently located south of eastern Rhode Island and west of about Cape May. After briefly pausing, the intensification trend has resumed, with the minimum pressure down to approximately 982 mb. The low pressure continues to track to the northeast but appears to be slowing down a bit.

As can be expected of most storms, there are parts of the area that are overperforming compared to the forecast, and others that are underperforming. In northwestern New Jersey, not much snow fell so far, while totals have been higher towards NE NJ; totals generally range from 3 to 8 inches so far. New York City is on the low side of totals, with Central Park reporting 2.5 inches as of 7 PM. Meanwhile, portions of Long Island especially further north in Suffolk county into Westchester county are overperforming, with 6 to 12 inches so far. Portions of southern Long Island continue to mix with sleet, and still have lower totals generally between 1 and 5 inches.

Most of the area is still seeing snow, with the exception of parts of southern Long Island still experiencing sleet. Heavy snow rates continue across northern Long Island and parts of Connecticut, with totals over 10 inches reported in some areas. New Jersey has dried up earlier this afternoon, although a narrow yet heavy band of snow remained stalled over extreme NE NJ, in northeastern portions of Bergen county, which did not enter the dry slot at any point. Snow is currently filling in across western New Jersey, with additional moderate to locally heavy snow spreading in and expected to remain in place through the mid overnight hours. Snow rates up to or locally a bit over 1 inch per hour can be expected west of NYC through the mid overnight hours, with at least another 4 to 8 inches of snow expected from NYC and further west.

5:40 PM: As of 5 PM, the low pressure is currently located south of central Long Island and east of extreme southeastern Maryland. The intensification rate has slowed down for now, with the minimum pressure near approximately 985 mb, as it continues to track to the northeast.

Most of the area has changed over to plain snow, with heavy snow rates up to 2-3 inches per hour in parts of Long Island. The heavy snow will continue over Long Island and Connecticut, with the forecast still for totals above 12-18 inches, up to or locally above 24 inches. Further west, the eastern movement of the west end of the precipitation shield has stopped over eastern NJ, with the shield pivoting towards more of a north-south alignment over eastern and NE NJ. As phasing continues to take place, precipitation from central/western New York and Pennsylvania will connect with the precipitation shield over the area, with moderate to locally heavy snow expected from NYC and further north/west through the rest of the evening into the mid overnight hours. In New Jersey, the highest totals are expected in the northeast part of the state with at least 10 to 15 inches of snow; lower totals are expected in NYC with 8 to 14 inches, with western parts of New Jersey expected to end up with at least 7-12 inches, lower in some spots and higher further east.


2:30 PM: As of the latest SPC Mesoanalysis, the low pressure is currently east of the southern tip of the Delmarva Peninsula and south of western Long Island. The low continues to steadily intensify while moving to the northeast, with minimum pressure currently down to 986 millibars.

Over the last 2-3 hours, rain and sleet continued across Long Island, NYC and parts of northern NJ especially south of I-80, although locations south of I-80 including parts of NYC and the northern half of Long Island are either seeing snow or changing to a mix, with heavier precipitation rates expanding north into the area. Precipitation is still struggling to expand into NW NJ, with relatively minor precipitation totals so far.

The low pressure will begin to tilt more to the north over the next few hours, with heavy precipitation moving into Long Island, Connecticut and the immediate NYC area, especially east of NYC, as the rain/snow line continues to shift south. Heavy snow is expected later this afternoon in the aforementioned areas, with snow rates reaching and exceeding 1 inch per hour. Western and central northern New Jersey, however, will remain west of the heavy bands, where lighter snow rates are expected late this afternoon and this evening. Later this evening or early tonight, moderate to heavy snow will spread into the interior western parts of the area as well. Accumulations are expected to end up in the 7-15 inch range in the western half of northern NJ and SE NY, approaching the higher end of this range further east with 10-15 inches in the immediate NYC area, perhaps locally over 15 inches in the snowier case scenario. Long Island and southern Connecticut are still on target to receive heavy snow tonight over 12-18 inches, up to and over 24 inches in some locations in Connecticut.

11:50 AM: The latest radar observations continue to show heavy rain bands over Delaware and southern NJ; despite earlier observations, however, the precipitation shield is now west of the short range HRRR/RAP models which take the heaviest bands noticeably east of NYC, and the latest observations suggest some, but not all, of the models may be a little too far east with the western extent of these bands through the rest of the day. Taking the western extent of the heavier banding over Delaware and drawing a tangent line along the western extent, hypothetically assuming the storm was to continue due NE, the heaviest bands would extend into most of Long Island and central-eastern Connecticut, which are still expected to receive over 12-16 inches with some areas over 20-24 inches. This will likely not be as far west as the bands get, however, as the storm will continue to tilt more towards the north later today, meaning the western extent is likely to end up west of this line through central-western LI and central CT.

Currently, the immediate NYC area (NYC, far southeastern NY, NE NJ) are in the borderline areas regarding the western extent of the banding, where totals are subject to more revisions. Should the heaviest bands stay east of NYC, totals would end up within the previously mentioned range of 7-15 inches west of NYC, leaning towards the higher end of this range (10-15"). Should these bands make the turn earlier, however, higher totals would be expected, potentially within the 12-18 inch range as well. Westernmost parts of the area are currently forecast to receive the 7-15 inch range as well, but are subject to the lower end of the forecast range, 10-12 inches or lower, depending on exactly how far the heaviest bands extend.

10:50 AM: As of this morning, the coastal low pressure continues to intensify; the latest SPC mesoanalysis as of 9 AM shows a 996mb low pressure near the eastern tip of North Carolina. Phasing will take place today as the low pressure continues to intensify and track to the northeast. Precipitation from the coastal low has spread into the area this morning, with the latest radar observations suggesting snow is falling west, southwest and north of NYC including parts of Long Island, with a mix or rain in NYC and further south.

As of last night, the model guidance was still split between an east and west track; the ECM, NAM and SREF were further west, although the NAM was a complete outlier last night with ridiculously high precipitation amounts over all of New Jersey, and has reasonably backed away, a rather large trend considering all of this occurred within 24-36 hours of the storm. The ECM and SREF, however, also corrected slightly further east, which also is supported by the latest observations, which suggest that the heavier precipitation from the coastal low will go into Long Island and southern Connecticut as last night's forecast expected, not in the immediate NYC area as some of the models suggested.

Forecast Update: Last night's discussion mentioned two areas of uncertainty; the western extent of the heavier precipitation from the low pressure, and the duration of mixing with sleet/rain. As of this morning, the southern half of the area is generally mixing with rain and sleet, with the mixing line showing some signs of advancing north. The rain/snow line is not expected to significantly change throughout the day, with the changeover to snow occurring across the area by the late afternoon to evening hours, generally after 5-8 PM when all of the area should change over to snow. The mixing with rain is expected to take up a part of the heavier precipitation of the storm in locations currently seeing mixing.

The second area of uncertainty was regarding how far west the heavy precipitation from the coastal low extends. As previously mentioned, the heavier precipitation will go into southern CT and Long Island, not NYC, but the question remains on how much precipitation does make it to NYC and further north/west, and at least for NYC how much of that falls as snow. Last night's update gave two scenarios; one in which the gradient is further east, with 6-12 inches of snow for NYC and further west with higher totals east of NYC; the second in which the gradient is further west and heavier snow totals spread across the rest of the area. Currently, the former is more of a concern than the second. The latest expectation is for a tight precipitation gradient roughly near NYC; an example of this is with the 12/26/10 blizzard, which also had a tight precipitation gradient over New Jersey, with eastern parts of the state seeing more snow than expected and western parts seeing less than expected.

While higher snow totals are still expected east of NYC, with at least 10 to 20 inches of snow in Long Island and 16 to 24 inches in southern CT, it is possible that totals in NYC, northern NJ and SE NY may end up lower than expected, with additional moderate snow through this evening but without heavy snow rates as the heaviest precipitation stays further south and east, and continued moderate snow overnight across the entire area. The latest forecast is for at least 7 to 15 inches of snow across northern NJ, SE NY and NYC; according to the latest model guidance, totals would mostly stay closer to the upper end of this range, but the lower end cannot be ruled out for parts of the area west of NYC as well, perhaps slightly lower than 7 inches in western areas. Stay tuned for more information on the storm and any changes in the forecast throughout the day.

Reposting the map from last night below - main revisions for the NYC area at this time are to shift the western end of the 12+ inch zone slightly east.