Snow Sunday?

This morning, all eyes will focus on a southern storm system moving towards the East Coast of the United States this weekend. The late night computer modeling shows that the steady precipitation staying south of New Jersey. Some snow showers or flurries could brush extreme portions of Southern New Jersey according to the latest information, but that is it.

Of course this winter has been full of northern and western trends. Therefore, one may need to watch for a northern shift within the next 24 to 48 hours. Cold, Canadian High Pressure to our north will be the key in blocking the storm with a cold, dry air mass.

While we may not get steady snow, especially south of Interstate 195, clouds will hang tough. Sunday could be a fairly cold day and later extended forecast graphics I develop may have high temperatures in the mid-thirties. Even if the steadier precipitation shifts further to the north, temperatures may still be cold enough for snow to be the precipitation type.

Round Two Tonight---Tough Forecast

Round one is done. For many portions of Morris, Bergen, Passaic, Warren, and Sussex Counties, they are using the snow blower. 5 to 9 inches were reported in these counties, with lesser amounts in the lower elevations. Essex County received 2 to 5 inches of snow. Somerset, Hunterdon, Hudson, Union, and Middlesex Counties generally got one to two inches, with localized three inch amounts. Monmouth, Burlington, Gloucester, Atlantic, and Mercer Counties have received localized trace to one-half inch amounts, although this quickly melted by daybreak. The counties that got 5 to 9 inches of snow met winter storm criteria (6 inches in these counties), so this was a much bigger deal than had been anticipated, with the advisory issued.

...ATLANTIC COUNTY...
PLEASANTVILLE 0.1 700 AM 2/21
ATLANTIC CITY AIRPOR 0.1 700 AM 2/21

...BURLINGTON COUNTY...
FLORENCE 0.5 500 AM 2/21
WRIGHTSTOWN 0.2 700 AM 2/21
MOUNT HOLLY WFO 0.1 700 AM 2/21
MOUNT LAUREL T 700 AM 2/21

...GLOUCESTER COUNTY...
NATIONAL PARK T 700 AM 2/21

...HUNTERDON COUNTY...
WHITEHOUSE STATION 2.2 725 AM 2/21
2 NW WHITEHOUSE STAT 1.8 755 AM 2/21
FLEMINGTON 1.8 830 AM 2/21
WERTSVILLE 0.8 730 AM 2/21

...MERCER COUNTY...
EWING 0.4 710 AM 2/21

...MIDDLESEX COUNTY...
METUCHEN 1.1 608 AM 2/21
NEW BRUNSWICK 1.0 800 AM 2/21

...MONMOUTH COUNTY...
FREEHOLD T 800 AM 2/21

...MORRIS COUNTY...
BUTLER 7.8 814 AM 2/21
1 NNE PETERSBURG 7.0 756 AM 2/21
MARCELLA 6.7 837 AM 2/21
BOONTON 5.0 900 AM 2/21
ROCKAWAY 4.0 730 AM 2/21

...SOMERSET COUNTY...
POTTERSVILLE 3.2 700 AM 2/21
BEDMINSTER 2.0 757 AM 2/21
BRIDGEWATER TWP 1.8 859 AM 2/21
SOMERVILLE 1.5 730 AM 2/21
HILLSBOROUGH 1.0 757 AM 2/21

...SUSSEX COUNTY...
NEWTON 8.0 850 AM 2/21
WANTAGE 6.8 809 AM 2/21
SPARTA 6.3 830 AM 2/21
FREDON 6.0 818 AM 2/21

...WARREN COUNTY...
BLAIRSTOWN 6.2 819 AM 2/21
BELVIDERE 4.0 755 AM 2/21
HACKETTSTOWN 3.5 735 AM 2/21
PHILLIPSBURG 2.5 708 AM 2/21
STEWARTSVILLE 2.4 715 AM 2/21

...BERGEN COUNTY...
MAHWAH 7.6 900 AM 2/21 SKYWARN SPOTTER
RAMSEY 7.3 830 AM 2/21 SKYWARN SPOTTER
1 SSE OAKLAND 7.1 845 AM 2/21 COCORAHS
ALLENDALE 7.0 1108 AM 2/21 PUBLIC
RIVERVALE 7.0 1100 AM 2/21 SKYWARN SPOTTER
RIDGEWOOD 6.3 700 AM 2/21 SKYWARN SPOTTER
ELMWOOD PARK 5.7 830 AM 2/21 SKYWARN SPOTTER
WNW OAKLAND 5.5 700 AM 2/21 COCORAHS
LODI 5.5 1029 AM 2/21 PUBLIC
ORADELL 5.4 900 AM 2/21 SKYWARN SPOTTER
EAST RUTHERFORD 5.0 1109 AM 2/21 SKYWARN SPOTTER
1 W TENAFLY 4.4 715 AM 2/21 COCORAHS
GARFIELD 4.2 800 AM 2/21 SKYWARN SPOTTER
1 E SADDLE BROOK TWP 4.0 830 AM 2/21 COCORAHS

...ESSEX COUNTY...
CEDAR GROVE 5.2 835 AM 2/21 PUBLIC
WEST ORANGE 4.3 900 AM 2/21 PUBLIC
MONTCLAIR 4.0 930 AM 2/21 PUBLIC
NEWARK AIRPORT 2.0 700 AM 2/21 FAA CONTRACT OBSERVER

...HUDSON COUNTY...
HARRISON 3.5 945 AM 2/21 SKYWARN SPOTTER
N HARRISON 3.0 800 AM 2/21 COCORAHS
HOBOKEN 2.8 930 AM 2/21 SKYWARN SPOTTER

...PASSAIC COUNTY...
RINGWOOD 8.0 930 AM 2/21 SKYWARN SPOTTER-900 FT
WEST MILFORD 7.9 1030 AM 2/21 SKYWARN SPOTTER-1100 FT
3 NE WEST MILFORD TW 7.5 330 AM 2/21 COCORAHS
WAYNE 7.0 858 AM 2/21 SKYWARN SPOTTER
1 SSE HAWTHORNE 6.5 900 AM 2/21 COCORAHS
1 WNW LITTLE FALLS T 5.5 900 AM 2/21 COCORAHS
1 SSW WAYNE TWP 5.0 700 AM 2/21 COCORAHS

...UNION COUNTY...
ELIZABETH 2.9 900 AM 2/21 SKYWARN SPOTTER



The temperatures this morning show quite a contrast, as expected, from northwest to southeast. It is around 25 degrees in Sussex County and around 45 degrees in Cape May County. Snow cover is impacting the temperatures in the north.

A cold front will approach from the west this evening. A pretty remarkable area of low pressure will be giving the front a boast and at the same time the low will be moving to our south. The models have shifted the axis of heavier snow northward over the past two days. This band will likely impact the areas that did not receive as much snow from this event. The latest 12z NAM guidance shows (without any mixing/temperatures taken into account) a general 2 to 6 inches of snow in Southern New Jersey with localized banding amounts of 6 to 9 inches in Southwestern New Jersey. The latest 12z GFS guidance shows a general 2 to 6 inches in Southern New Jersey. There appears to be a very sharp cutoff on both models. On the NAM, it is arguably at Interstate 195. On the GFS, it is at or just below Route 537 which runs through Burlington and Ocean Counties. The NAM has been excellent at picking up convective features and banding this season, and I do buy the banding it shows moving across Southern New Jersey leading to the higher amounts. This is what the guidance is spitting out if it were all snow, but not the forecast.

This evening, colder air will begin dropping our temperatures prior to the daylight ending. Over the north, skies could even have breaks in the clouds allowing extremely cold temperatures to settle in. In Central New Jersey, temperatures will drop through the thirties quickly to or below freezing. In Southern New Jersey, temperatures will drop from maximums anywhere between 40 and 50, depending on where you live. What will be so critical here is determining the surface temperature and the temperature all the way from top to bottom in the column. Since temperatures could initially be above 40 degrees when the precipitation begins, it could definitely start as some rain and sleet in just about everywhere that receives precipitation tonight. It is expected, based on the “540 Line” sinking to the south on both the GFS and NAM, that even if the surface is above freezing, the temperatures to air near the surface will cool with colder air advection moving in, allowing the rain to change to sleet and wet snow, even down in Cape May County. But during this process, the heaviest precipitation may be in Cape May County, but it will be warmest here. So the greater snow totals could actually fall along a corridor of the Atlantic City Expressway. It is going to be absolutely nail biting trying to pin down this snow and sleet accumulation with transitions and warmer surface temperatures. In Northern New Jersey, at least temperatures were closer to freezing when the snow started there late last night and early this morning. With all of this in consideration, I think many areas will receive 1 to 3 inches of snow. There could be a banding situation where once it is all snow and temperatures are plunging, a localized strip could pick up 2 to 6 inches of snow. Keep in mind that an advisory criterion in this part of New Jersey is two inches and warning criteria is four inches.

Gradient wise---the cutoff will fall somewhere between Interstate 195 and Route 70. This could just be like lake-effect snow where even cities and towns have very different conditions from one end to the other.

It is worth noting that previous events (very similar) over the past two decades… where banding occurred in these areas…resulted in 8 to 12 inches in a localized strip and the other event resulted in 5-9 inches. These bands ran from York County down through Gloucester and Atlantic Counties. But again, we have mixing and a warmer ground this time. Regardless, this forecast has very high busting potential.

Wintry Mix Threat Tonight for Some, Snow & Sleet Threat Late Monday into Tuesday for Some

Trouble could be brewing.

System number one is only about eighteen hours away. The computer model guidance this morning is much colder and shows more available liquid with the 12z Guidance for Northern and Central New Jersey. The “540 Line” on both models never really lifts through Central New Jersey on both the GFS and NAM models during the heaviest precipitation. Temperatures this morning are running several degrees colder than the guidance indicated. The column also seems to be colder when peaking at the atmospheric profiles.

It would appear as though some areas may see the precipitation start as wet snow, with a mixture of sleet where the precipitation is heavy enough. There still is expected to be a transition to rain in Central New Jersey, but this could be delayed until the steadier precipitation turns lighter and more sporadic. Meanwhile, it still appears that south of the Atlantic City Expressway, the precipitation will be light and the likely conditions would be fog and drizzle. But, if heavier showers should occur here, they may contain some sleet pellets initially. It could be a very interesting temperatures situation on Monday Morning with a huge difference from north to south.

The models continue to show a lull during Monday, around midday. A second low pressure area will pass to our south on Monday Night into Tuesday. However, the 12z Guidance has trended further to the north. As you can see from the previous post, the NAM model has the heavy axis of precipitation in Delaware last night. The latest 12z NAM model shows the heart of this site’s forecast area seeing that band of heavier precipitation. Even the GFS from 12z has shifted further to the north, showing the heavier band including more of Southern New Jersey. The models also seem to be a bit colder with this storm as well, indicating a faster transition to sleet and wet snow.

With the transitioning precipitation and the bouncing back and forth on the models, it is very hard to make a snow and sleet graphic prediction. I think someone could end up with as much as four to six inches of snow and sleet when this is all said and done…but where is the question that really doesn’t have an answer at this late hour.

Morning Commute Change to Wet Snow?

I continue to watch the period around the morning commute for problems in New Jersey due to frozen precipitation. A strong cold front is being projected to sweep the area between 5:00 a.m. and 9:00 a.m. Precipitation has an opportunity to intensify ahead of this cold front as there appears to be strong convergence which will produce some lift in the atmosphere. The models for days have been indicating interaction with the offshore energy and although the models have lost it late tonight, I believe it is a plausible scenario. The scattered rain showers and pockets of drizzle could evolve into more concentrated (possibly narrow or squally) area of steady precipitation during the commute, as the front comes in. The precipitation is forecast to change to wet snow and sleet at this time and it could be a nasty hour or two in some spots with reduced visibilities and even a quick coating of snow. The coating of snow will be hard to earn as the ground will be wet and initially above freezing due to the temperatures early this morning, but it can be achieved with a heavy snow rate and dropping temperatures. There certainly could be an isolated thunderstorm which could cause some heavy snowfall since there are steep lapse rates. Temperatures will drop as the snow begins and they could go down to around freezing north of the Atlantic City Expressway causing some icy conditions.

I certainly don’t have the highest confidence in this change to wet snow and sleet playing out as planned, but there is a possibility of this happening and it warrants being highlighted. If this does happen later this morning, the timing would classify it as a high-impact winter weather event.

We then focus on the windy conditions which have the potential to cause problems with weakened tree branches and trees as gusts could be up to or in excess of 50 MPH for a time later Tuesday Morning into Tuesday Evening.

Updating The Snow Threat Early Tuesday Morning

The newest North American Model run from 00z is now in and looks very similar to the 12z and 18z Global Forecast System Model. The NAM is now showing a stronger wave developing along a strong cold front expected to pass through our region and the NAM clearly shows the wave interacting with energy coming up from the Southeastern United States that will pass to the east of New Jersey. The majority of the precipitation according to the NAM comes when the “540 Line” is more than 200 miles offshore. This suggests a light accumulation of snow and sleet as there is 0.10” to 0.25” of liquid to work with according to the model.

Of course, the 00z GFS looks more like the 18z NAM with the area of 0.10” to 0.25” of available liquid more confined to Northern New Jersey.

The higher resolution models continue to show mainly rain over New Jersey, but I am very doubtful of this if the “540 Line” is well offshore as both the GFS and NAM agree on during the majority of precipitation.

Certainly it looks like any rain and rain/snow mixture will be going over to snow and that there could be a light accumulation early on Tuesday Morning which may cause hazardous travel for the morning rush hour. There are two possibilities after analyzing all of the model runs over the past eighteen hours. Either this will be confined to Northern New Jersey or it will affect all of New Jersey. Afterwards, winds will begin to gust between 40 and 50 MPH once the clouds begin to clear and temperatures drop throughout the afternoon hours on Tuesday.

There is a low probability the Southeastern United States moisture tracks closer to the coastline and gives us more significant precipitation on Tuesday Morning.

Watching The Next System for Monday Late-Tuesday

A strong cold front will cross the area on Monday Night into Tuesday. It is appearing as though most of the precipitation will fall after the colder air arrives. This means that we could be dealing with some snow squalls or snow/sleet showers that could end up giving us a six hour period of light snow and sleet accumulation. Before that cold air advection comes in, we have the chance for rain or rain and snow showers.

The models seem to hint at low pressure developing along this front as it crosses our region which would intensify the precipitation along the boundary. This frontal passage will have to be monitored for interaction with moisture coming up from Florida to see if it would generate a coastal low or intensify a low forming on the front further. The frontal passage could usher in some fairly good wind gusts.

00z GFS: Shows the best chance for of 1-3 inches of snow in Northern New Jersey.

00z NAM: Shows the best chance for 1-3 inches of snow in Southern New Jersey.

I think it will a compromise between the two possible solutions. One thing is for sure, this storm will be very critical in setting the stage for a potential late week storm.

Snow Update----No Real Change in My Forecast

A winter weather advisory remains in effect for all of New Jersey with the exception of Coastal Atlantic and Cape May County.

The 00Z, January 21, 2011 data has just been printed. Based on the data, my forecast looks to be mainly on target from earlier today. If I were to make any change….it would be expand the two to four inches of snow on the map into Northeast New Jersey and focus the three to six inches of snow area more towards New York City. I think the one to three inches over an expansive area remains very appropriate.Based on the latest high resolution model update, I still see the rain and sleet mixture across Southeastern New Jersey with a battle zone in an area with temperatures around freezing along that Atlantic City Expressway and Route 70 corridor. If the NAM is correct with less precipitation overall in these areas and we have some mixing, we would see amounts on the lower end of the one to three inch range in these areas. I still would anticipate a zone of glazing due to some light icing.

The snow has yet to begin in New Jersey. So far the storm has been struggling to fight some drier air. I expect this to begin to change around Midnight and some precipitation should begin to break out with the radar filling in after 1:00 a.m. The heaviest snowfall will be between 3:00 a.m. and 6:00 a.m. The snow will end during the morning commute from west to northeast. Only so much snow can fall in the time frame given. Therefore, even if this coastal storm gets cranking rapidly, we have limited time to take advantage of it. Thus far, the coastal storm has yet to develop as there is no real area of precipitation offshore.

The areas that see snow will see a wet snow. The drier and powdery snow will be towards Northwest New Jersey and the Poconos. The area over the Chesapeake Bay is one of the areas I will be watching over the next two hours for blossoming.

When we awaken, we will know the outcome. :-) As I said earlier, this storm is a hard one to forecast and has a high bust potential.

Winter Weather Advisory, New Snow Map After 11:00 a.m.

Just peaked at newest GFS and some higher resolution models...mixing towards Cape May and heaviest axis of snow may fall near NE NJ. Map will be delayed as I am waiting for the the EURO.
The National Weather Service has placed all of New Jersey under a winter weather advisory.

After looking over the new information from both around 2:00 a.m. and 9:00 a.m., some increase in the snow amounts appears to be warranted. The heaviest snow axis seems to have expanded, while shifting above the Delaware Bay. I will wait for the GFS model to come in around or before 11 a.m. A new snow map should be out before noon today.

Snowfall Forecast for Late Thursday into Friday Morning

With the latest computer model guidance in, I am ready to put out a preliminary snowfall map. A clipper system will approach from the west. As it does so, a coastal low pressure area will form offshore. The models over the past 12 to 18 hours have indicated that this low pressure area will not intensify rapidly until the storm is off the coast of New England. The models have also indicated this low pressure area will be further offshore. The result is a colder storm and I do not see mixing being a factor in coastal sections of Southern New Jersey or Central New Jersey. This will be a snow event. If any warm air was to make it into the region, it would be along the very immediate coastline.

The other thing going against substantial snowfall at this hour is the fact that this is a 6 to 8 hour window of snowfall. The snow will begin between 10 p.m. and 12 a.m. on Thursday and shut off from west to east on Friday Morning just before or during the morning rush hour.

At this time, I do not believe there will be more snowfall to our north and west. I see the heaviest precipitation actually occurring over Eastern Long Island down through Eastern Delaware. The coastal counties of New Jersey are in the middle of the corridor of heavier precipitation. The models are indicating the most precipitation in New Jersey.... with 0.10 to 0.25 available in much of the state according to the NAM model and 0.25 to 0.50 inches available according to the GFS. The latest NAM is not too aggressive with amounts south of the Atlantic City Expressway (showing just a trace of snow to a coating). I think the latest 00z NAM is too dry and I am looking at the prior 12z and 18z runs which is more in line with the GFS from 00z. In fact the GFS output for New Jersey on the 00z run is a bit more than 12z and 18z.

Snowy Late Thursday Into Friday, But How Much?

There will be snow on Friday and there is no debate about it.

The question at this point is will it be an average of 1-3 inches of snow throughout New Jersey or will there be snowfall in excess of 4 inches.

The North American Model has been bouncing the snow totals around. One model run will have the low stronger and closer to the coast and then the next run will show a weaker, further offshore storm. For instance, today at 06Z it shows a fairly substantial snowfall and the new 12Z run shows a light accumulation of snow.

The GFS model at 6Z shows about 3-6 inches, maybe a bit more, for Central and Southern New Jersey. The GFS model in from 12Z shows generally 1-3 inches for Central New Jersey and 3-6 inches in Southern New Jersey.

Later today or tonight, with the extended forecast, I hope to throw out preliminary snowfall total maps. These can be fine tuned as we approach Thursday Night into Friday.