[notice]Regular forecast discussions will resume later today. In the meantime, the 8-day forecast has been updated.[/notice]
Occasional updates will be posted below on the snow and wind event affecting the region today and tonight. Radar images are from the Pennsylvania State University e-Wall.
Links: Yesterday’s forecast | 8-Day Forecast | Twitter | Facebook
Current storm snow totals in NYC: (Updated 7am)
Central Park – 6.0″ | LaGuardia – 6.9″ | JFK Airport – 6.6″
7:45 AM: Snow Tapering Off
As of 7 AM, the low pressure is south of eastern Maine and east of southern NJ, having become increasingly consolidated following last night’s updates. Minimum pressure is near 987 mb, and the low will continue to steadily deepen as it tracks northeast and out of the region.
Since the last update, a band of heavy snow moved west to east through the immediate NYC area and Long Island/coastal CT around 2-4am, leading to temporarily higher snow rates up to 1″ to locally 2″ per hour. Snow then began to shift offshore, but with the inverted trough feature developing between Long Island and coastal NJ, where snow totals up to 10-12 inches have been reported. Although the snow has not ended yet, preliminary reports suggest the lower totals were found over parts of northeast NJ and CT, with the highest totals in coastal NYC and Long Island.
The snow will gradually end over the next 2 hours, but the cold temperatures will stick around, as current temperatures range from 6 degrees in Sussex, NJ to 11 degrees in Central Park and 13 degrees in Islip, NY, which is unusually cold for a snowstorm in the NYC area. Cloud cover will gradually clear today with highs in the low-mid 10s inland and mid-upper 10s elsewhere, with wind chill values between 0 to -10 degrees especially early in the day. With decreasing winds tonight, temperatures will fall into the negative single digits across most of northern NJ, SE NY, and CT/LI away from the coast, getting as low as the -5 to -10 degree range in NW NJ and SE NY. NYC is currently likely to reach at least 3 degrees, which would make it the coldest temperature in Central Park since January 10, 2004, when temperatures fell to nearly 1 degree. The last time temperatures fell below zero in Central Park was in 1994.
This is the final storm update. The next forecast update regarding the upcoming pattern and next week’s arctic outbreak and flash freeze on Monday will be posted later today.
1:15 AM: Snow Continues through Friday Morning
As of 1 AM, the low pressure is east of southeastern VA. Minimum pressure is near 994 mb, and the low will continue to consolidate as it tracks northeast.
Widespread moderate snow covers the area at this time, including NE NJ and SE NY, falling heavily at times especially east and south of NYC. Widespread snow totals of 2-5 inches have been reported across the area, with the highest totals in Long Island and south of NYC. The main precipitation shield continues to slide offshore, but with moderate snow persisting as an inverted trough will begin to take shape tonight, leading to an enhancement of moderate snow over parts of the area into central NJ. Snow is generally expected to taper off between 7-9am from NW to SE. Temperatures continue to cool down with strong northerly winds advecting frigid temperatures in Canada into the area, and are currently in the single digits across most of SE NY and northern NJ and in the 10s elsewhere. Along with the strong winds, wind chill values will fall to near -5 to -10 degrees across the area tonight into Friday morning.
Clearing skies are expected on Friday with windy conditions leading to blowing snow and highs only reaching the low 10s inland and the mid to upper 10s elsewhere, making tomorrow the coldest day across the area since January 2009. Decreasing winds are expected overnight as NYC and the coast fall into the mid 0s with north/west suburbs close to zero and locations further inland, including interior Long Island, expected to fall below zero, getting as low as near -10 degrees in NW NJ and SE NY.
This is the final storm update for tonight. Another update will be posted on Friday morning, followed by an in-depth forecast discussion in the afternoon or evening regarding the extreme arctic cold outbreak expected across the majority of the central and eastern US next week.
11:35 PM: Peak Of Storm Underway
As of 11 PM, the low pressure position is east of Cape Hatteras, NC extending northeastward. Minimum pressure is near 998 mb, and the low will continue to consolidate and deepen through the overnight hours.
Since the previous update, the heavy precipitation over southern New Jersey has shifted southeast and offshore, with decreasing influence from the subsidence over northeast NJ and SE NY. This is reflected with the latest radar as steady moderate snow rates are gradually spreading north towards the I-80 corridor. While the earlier lack of heavy snow is expected to keep precipitation totals slightly lower over these areas, continued moderate snow through the late overnight hours will partially offset the evening lighter snowfall rates, with totals likely at least 1-2″ lower than the remainder of northern NJ and NYC, where a general 6-10 inches of snow are expected.
As the coastal low continues to intensify, steady moderate snow, locally heavy near and south/east of NYC, will continue through the mid overnight hours, along with strong northerly winds at 20-30 mph leading to near blizzard conditions, while temperatures continue to fall into the low-mid 10s for most locations and the mid-upper 0s for NW NJ and SE NY, leading to wind chills in the 0 to -10 degree range. By the early morning hours, the inverted trough feature is expected to focus just south of the area, with snow winding down by 7-9am.
10:15 PM: Less Snow over North NJ, SE NY
As of 10 PM, the low pressure position has shifted slightly east of the previous update. Minimum pressure is near 1000 mb, and the low pressure continues to gradually deepen as it tracks ENE.
While most of the area continues to see moderate to occasionally heavy snow, the high resolution model guidance failed to depict an area of subsidence over parts of northern NJ, specifically over Bergen and Passaic counties, extending into parts of the lower Hudson Valley, where radar reflectivity has yet to reach 20dbz. This can be seen in the NWS regional radar, posted to the left, with the inland extent of the moderate snow reaching NE PA before shifting southeast along the NY/NJ border and resuming a NE path over New England. Snow will eventually increase in intensity, mainly after 11pm-12am, but with a shorter duration than the rest of the area. Given current snow reports, updated as of 10:30pm, these locations are likely to see the lowest snow totals across the area, with at least 5-8 inches of snow expected with locally higher amounts. Otherwise, totals of 6-10″ are expected elsewhere in northern NJ south of I-80 to I-78 and interior SE NY, with the forecast snowfall remaining unchanged over Long Island and southern CT.
9:00 PM: Snow Forecast Update
As of 8 PM, the broad low pressure area is beginning to slightly consolidate off the North Carolina/Virginia coast. Minimum pressure is near 1002 mb, and the area of low pressure will continue to consolidate tonight as it tracks ENE, then northeast while rapidly deepening.
The area is now covered by moderate to heavy snow, especially along and south/east of the I-95 corridor where up to 1-2 inches of snow have been reported so far. The earlier snow bands struggled to expand north of I-80, however, although the initial heavy snow bands are currently shifting southeast, while a narrow axis of lighter reflectivity is shifting southeast as a broad area of moderate snow is developing over eastern Pennsylvania and the rest of New Jersey/SE NY. Snow rates will temporarily lighten up over the immediate NYC area and Long Island, with moderate to occasionally heavy snow expected to resume after 10pm or so. Temperatures will continue to steadily fall into the 10s, and the upper 0s in interior areas, while winds increase to 20-30 mph leading to near blizzard conditions especially in Long Island.
The latest high resolution models continue to depict at least 0.60″ to 0.75″ of liquid-equivalent precipitation across the area, which would be higher than 6-7.5″ considering that snow ratios are generally above the standard 10:1 ratio. Locations north and west of NYC, however, have not yet had as much snow as modeled, with persistent areas of lower reflectivity positioned over parts of northern New Jersey. Considering the above and the latest indications for the inverted trough to set up potentially over southern parts of the area, the latest snow outlook remains at 5-10″ in northern NJ, with the lower totals closer to the NJ/NY border and higher totals towards the I-78 corridor; 6-11″ in SE NY, with the lower totals further south and west; 7-12″ over southern CT and NYC, with the higher totals closer to coastal areas; and 8-12″ over Long Island, with localized totals over 12 inches possible.
7:00 PM: Moderate Snow Developing
As of 6 PM, there is no well defined surface low pressure center, with multiple centers spreading from Virginia to off the coast. Minimum pressure of the system is near 1003 mb, and as phasing occurs tonight, the broad low pressure area will consolidate and quickly deepen while tracking northeast.
Over the last 2 hours, the dry slot has filled across the area, with widespread light to moderate snow. NYC and northeast NJ, however, remain under a small dry slot, with flurries to light snow showers. This dry slot is expected to fill in within the next hour or two as steady snow spreads into the area. The most impressive observations from this system so far have come from southeast Massachusetts, where continued heavy ocean-enhanced snowfall and very high snow to liquid ratios resulted in snow totals significantly exceeding the forecasts, with reports of up to 20 inches of snow so far. In the end, these locations may end up with over 25-30 inches in isolated spots.
Over the NYC area, the short range model guidance continues to slowly trend towards more precipitation and higher snow totals, with the latest 22z RAP run depicting 0.60″ to 0.70″ of precipitation over the area, compared with the mid afternoon runs depicting 0.45″ to 0.55″ of precipitation. Along with increased snow ratios overnight, this would imply at least 8-12 inches of snow. While these totals may not be found across the entire area, the potential is there for more snow than previously forecast, which will continue to be monitored. Any revisions to the forecast will be made with the next update, to be posted between 8-9pm.
4:40 PM: Snow Entering Area
As of 3 PM, the low pressure is located over West Virginia. Minimum pressure is near 1004 mb, and the low is steadily tracking to the east. Additional deepening is expected over the next few hours as the low emerges off the Mid Atlantic coast and produces widespread moderate to heavy precipitation across the region.
Since the previous update, the dry slot has completely filled over Pennsylvania, with widespread moderate snow currently over eastern Pennsylvania, steadily tracking northeast towards the area. Snow is expected to begin between 4-5pm over northern NJ/SE NY, and 5-6:30pm in Long Island and southern CT. A stronger northerly wind is then expected with temperatures beginning to fall into the low 20s outside of interior locations with moderate to heavy snow likely covering the area by 6-8pm.
Forecast Update: The main features to keep an eye on tonight include the westward extent of heavy precipitation and banding from the main precipitation shield tonight, and the setup of an inverted trough expected to develop on Friday morning, enhancing snowfall for parts of the region. While the heaviest banding is expected to remain offshore, areas of heavy snow are expected primarily near and east-south of NYC tonight, with liquid-equivalent precipitation ranging from 0.45 to 0.65 inch across the area. As mid level temperatures rapidly cool down, snow ratios are expected to increase to at least 12:1 to 15:1, with the highest ratios likely towards early Friday morning. The inverted trough is expected to set up early on Friday morning, with most locations drying up by 7-8am but with the inverted trough extending the moderate-heavy snow a bit longer with snow ending by 8-10am. Today’s global model runs such as the ECM and GFS depicted the trough over the NYC area, with at least 0.70 inch of precipitation over NYC with higher totals further east and southeast. The higher resolution models, such as the RAP and 4k NAM, however, depict the inverted trough as setting up south of the area, with enhanced heavy snow over southeast PA and central-southern New Jersey. At this time, I am expecting the heaviest snow from the inverted trough to set up south of the area, towards coastal central-southern New Jersey.
Looking across the region, the highest snow totals are expected over southeastern Massachusetts, where the previously noted coastal low and ocean effect-enhanced snow, combined with very high snow-liquid ratios near or over 20:1 resulted in totals as high as 6-8 inches so far, with storm totals in that region into Boston expected to reach the 14-20 inch range. In the NYC area, the aforementioned factors support at least 5-10″ in northern NJ/NYC, 6-11″ in SE NY, and 7-12″ in Long Island and southern CT. With the inverted trough setting up south of the area, however, yesterday’s snow map is likely too low from Baltimore eastward into Delaware and south-central New Jersey, with totals up to 8-12″ or locally higher possible under the inverted trough near coastal parts of New Jersey.
2:05 PM: More Snow on the way
As of 1 PM, the low pressure is located near southwestern West Virginia. Minimum pressure is near 1006 mb, and the low is steadily tracking to the ENE. The low is expected to pass through Virginia late this afternoon before tracking offshore and quickly deepening overnight while passing southeast of the 40N/70W benchmark.
Over the last few hours, the weak coastal low shifted east with the snow bands gradually shifting into southeast Massachusetts, where along with ocean effect snow enhancement moderate snow totals have already been reported. Other than a few isolated snow showers, mixing with freezing drizzle at times, the area stayed dry. Current temperatures range from the mid-upper 10s in NW NJ/SE NY to the low-mid 20s in NYC, the north/west suburbs and coastal CT, and the upper 20s-low 30s in Long Island. The dry slot has began to fill in over western Pennsylvania, with snow already spreading into central Pennsylvania. Light snow is expected to begin spreading in from west to east around 4-6pm, gradually intensifying and becoming moderate by 6-8pm. At this time, the snow outlook remains unchanged, although an area of uncertainty is regarding the inverted trough expected to slightly prolong moderate-heavy snow on Friday morning through 7-9am, along with higher ratios likely near 15:1. The latest runs of the GFS, ECM and high-resolution NAM support this setting up near the area, although the exact placement is uncertain and may shift a bit south of the area. This will be monitored for the possibility of slightly higher totals than currently forecast especially along the coast. The westward extent of the moderate-heavy snow bands this evening will also be a major factor regarding total snow accumulations, with further east banding resulting in slightly lower totals than currently forecast.
9:30 AM: Steady Snow Holds Off Until Evening
As of 9 AM, the low pressure is located near central Kentucky. Minimum pressure is near approximately 1010 mb, and the low is steadily tracking to the ENE.
While most of the precipitation affecting the region is associated with the main low pressure, extending into Ohio and NY state, another weak surface low is positioned just south of Long Island, with occasional bands of light-moderate snow moving from south to north into Long Island and Connecticut. Generally light accumulations below 1/2″ to 1″ are expected, with the low anticipated to shift slightly to the northeast, with the snow bands focusing over southeast New England by 12-2pm with dry conditions covering most of the area.
The main event will occur this evening as the low pressure enters West Virginia and tracks towards the coast, with the moderate precipitation currently over Kentucky and Ohio spreading into Pennsylvania and New Jersey. Steady moderate snow is expected to develop after 6-8pm from west to east, falling heavily at times especially near and south/east of NYC. Winds will increase to 20-30 mph from the north, leading to low visibility and near blizzard conditions – although it is important to emphasize that a blizzard is defined as 3+ hours of 35+ mph sustained winds with snow leading to low visibility, and is not related to the actual snow totals. Temperatures are expected to quickly fall into the 10s overnight and the upper single digits in NW NJ/SE NY, which will lead to wind chills in the 0 to -10 degree range for most locations tonight into Friday morning. Snow ratios are expected to remain near 10:1 at the start of the event, increasing to 12:1 to 15:1 by tonight into Friday morning, which will lead to slightly higher totals than modeled precipitation would suggest, which is at least 0.50″ in NYC. Overall, the snow forecast is for 5-10″ in northern NJ and NYC, 6-11″ in SE NY, and 7-12″ in Long Island and coastal CT with locally higher totals possible.
7:45 AM: Light Snow Falling in NYC, Long Island
As of 7 AM, the low pressure is located near western Kentucky. Minimum pressure is near 1013 mb, and the low will continue to slightly deepen as it tracks ENE into West Virginia. It is expected to cross into the Atlantic Ocean later tonight, when more rapid deepening will occur as the system tracks southeast of the 40N/70W benchmark.
Over the last few hours, the overrunning snow has been focused north of the area. Some light snow has spread into Long Island, NYC and northeast NJ, with at least a coating of snow with locally higher totals that hasn’t been well reflected on the radar in some cases. Occasional light snow will continue in Long Island and NYC through the evening with up to an inch possible, followed by more widespread snow developing after 6-8pm from west to east.