There is no doubt tonight will be a very cold night with record-challenging low temperatures likely over a widespread area. Last night, the rural suburbs of Central New Jersey went down to 8 degrees below zero and in some cases 9 degrees below zero. These temperatures are unprecedented for New Jersey. Ideal conditions developed where you had clear skies, calm winds, an arctic air mass, and a decent snow cover. Tonight, we have a reinforcing shot of arctic air along with clear skies and expected decoupling winds. However, the wind speed will be critical. If the wind is not calm, you may have values around zero, but not as far below as early today. At this present time, I will go with a range of 10 below zero to 5 above zero for minimum temperatures. Your higher minimums will be in the urbanized areas. You will also find higher minimums in Southwestern New Jersey where there is less snow cover.
If there is just the slightest breeze, hazardous wind chills will be possible. The wind chill advisory criteria for Central and Southern New Jersey is when there are wind chill values of 10 degrees below zero. For Northern New Jersey, it is 15 degrees below zero. The wind chill warning criteria is 25 degrees below zero. I do not believe anyone will reach the warning criteria, but it may come close in Morristown or Somerville should these areas drop to around 10 degrees below zero early Monday Morning. I definitely think wind chill advisory levels could be reached again because even the slightest breeze with the temperatures we are forecasting can take us to the criteria threshold. Frostbite usually occurs within one hour when we see values such as the ones I am forecasting tonight and the advisory levels usually mean frostbite will occur within one-half hour. Right now the National Weather Service will not be issuing the product, but I can easily see us reaching this criteria. The criterion was met in several areas last night just by temperature and the product was not issued.
Regardless of whether you have an advisory or not, it is highly recommended that you bundle up before going outdoors in the morning. Make sure the kids are also wearing a jacket, hat, scarfs, and gloves as sometimes they can be waiting at a bus stop for more than one-half hour or they walk a long distance to school.
A 5 MPH wind & a temperature of 10 degrees combine for a wind chill of 1 degree above zero.
A 5 MPH wind & a temperature of 5 degrees combine for a wind chill of 5 degrees below zero.
A 5 MPH wind & a temperature of 0 degrees combine for a wind chill of 11 degrees below zero.
A 5 MPH wind & a temperature of -5 degrees combine for a wind chill of 16 degrees below zero.
A 5 MPH wind & a temperature of -10 degrees combine for a wind a wind chill of 22 degrees below zero.
Monday will be the first day in quite a few years where the majority of New Jersey will not rise out of the teens for high temperatures. The best chance of hitting 20 degrees will be in the cities and along the coastline. It should remain sunny for the entire daylight period. Some clouds will arrive on Monday Night.
Tuesday at this point looks to be mostly cloudy as some warm air advection streams into New Jersey. At this point, the models are now keeping much of the area relatively dry.
The big question for Wednesday is will there be a major winter storm or not. Every single possibility that could happen has been thrown out there. The models are in a great deal of disagreement. Yesterday the GFS model indicated an out to sea solution as the cold air will be entrenched and block it from striking us. The GFS lost this idea late last night and I thought we would be in the clear. But now the 18z NAM and 18z GFS has brought back the idea of the storm going out to sea. Just know that the models seem to develop a westward shift overtime prior to the event. If that was the case, perhaps it is not close enough for a mix…but close enough for at least some snow.
The modeling delaying this storm until Wednesday would lead one to think that the core of the arctic air has time to exit the region. Therefore I would think that the very cold air would not be entrenched for the storm and that it would also be weak enough to prevent strong blocking that would protect the Middle Atlantic. This is such a strong outbreak of Arctic air that I cannot rule out that it lingers into Tuesday. Right now, I see highs around freezing for Tuesday. While I am skeptical of the idea of an out to sea storm, I can see the credibility of this idea when looking at the extent of the current cold and reviewing previous storms of the past decades that turned out to sea when approaching a very cold air mass.
For the moment, I will push this idea to the side. However, I will not hit the delete button on it quite yet. If we see a coastal storm, it looks to be centered to strike New Jersey on Wednesday.
I noticed something very interesting today on the North American Model run from 12z which I think could be more credible than the newest run. This run showed the rain and snow line setting up along the Delaware River in South Jersey and along Interstate 195 in Central New Jersey. With our previous storm system, this is exactly where the rain and snow line stopped. Today when I was in Monmouth County, as soon as you travel north of Interstate 195, not even by a mile, all of a sudden you run into a fresh snow cover. My observer in Riverside also noted that she picked up more snow than in the rest of Burlington County. This also confirmed the radar imagery with the last storm showing that this is where line of difference set up shop. Also, similar to the previous snow, colder air would come in at the end of the storm changing any mix or rain back to wet snow. The only differences on this run from the previous storm are that the storm would last longer, contain more moisture, and be stronger.
The 12z GFS has the storm further offshore, giving New Jersey precipitation, and not much west of the Delaware River. This would give the coastal sections the most precipitation. This track would be colder with snow inland and rain along the coastal counties with mixing in-between. To repeat, the 18z GFS shows no storm at all.
If we should see a storm track where the area of low pressure rides over our region, as the ECMWF suggests…we would see rain and the dividing line between rain and snow would push into Northwestern New Jersey. The EURO has been the only model of consistence. It is worth watching the model to see if it also trends offshore. We will not know until 1:00 a.m.
However, SHOULD WE see the storm track JUST offshore, I am thinking that the dividing line will set up along the Delaware River and along Interstate195. North of this area there could be heavy snow and sleet, along with freezing rain. It should be noted that no storm is exactly alike. I am also thinking that for the first part of the storm, just as in the previous storm, there will be a battle zone between County Route 537 in Burlington and Ocean Counties and the Atlantic City Expressway. This is the zone where cold air damming could make all the difference between rain and freezing rain. For Atlantic City and Cape May, these areas look to see a brief mix or no mix at all with a coastal hugger. Again, a further offshore track could mean mainly snow or no precipitation at all.
This storm has the potential to be loaded with moisture if it does strike, particularly with a close track. In fact even though you see the newest American models showing an out to sea solution, the precipitation associated with the system is quite impressive. This raises several concerns IF this is in fact the case. If the cold air damming holds on the onset…..just in those first few hours you could have several inches of snow or quite a bit of ice accretion before the change to liquid rain in some areas. Where it remains all snow in New Jersey, if it does at all, you would be talking about a substantial snow accumulation. Where it remains ice, you could be talking about a serious accretion of ice. Finally, where it rains, due to the wet ground, we could have some flooding concerns. The prospect that New Jersey could be divided into three sections by precipitation types is certainly interesting. Then again we have this brush of a storm idea which would mean just an average amount of liquid we would have to play with or really none at all.
Wind could be a factor as well if this storm is a coastal hugger or if it tracks over us. The track is critical in determining the wind speed and wind direction. This has consequences as far as the chance of coastal flooding. If it coincides with heavy snow or heavy ice…there could be some power outages. If there is heavy rain, the ground could be very soft and it would not take much more than a 40 mph gust to take down some shallow rooted trees. Areas that see strong winds and heavy snow may be looking at near blizzard conditions. The idea with this rambling and throwing out all these possibilities is to get you thinking about what may happen with each of these different scenarios’ that have been thrown out at us.
Model flip-flopping makes this a very difficult forecast. We are still 72 hours away from this event. It is also interesting that the new NAM model is showing this storm at our latitude late Wednesday, which would result in a further delay. This storm looked to be hitting us on Tuesday yesterday and this would have put us in the 48 hour period where we would have much better confidence. Now with this starting later on Wednesday, we may have to wait until Tuesday Morning before getting a much better idea.
Other notes: I am also a part-time forecaster for the site http://phillyweather.net . I will also be filling in for the site founder this week as he is going to be out of town on business. So check that site out as well. Brian, a founder of the site http://cnyweather.blogspot.com is also a colleague on that site and will be filling in as well. If you headed up to Oswego at any point in the future, be sure to check out his forecast for that area.
for updates as new information streams in.
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