Wednesday / Thursday Storm (Wednesday Afternoon Update)

First and foremost, our storm is really taking a toll in the Southeastern US. Snows and ice are really hitting an area hard that is not normally accustomed to this. I can only hope everyone down there follows their forecasts and have plans done accordingly.

For our area up here, we are about 10 hours away from the start of our storm. As you can see, we are dealing with a very large storm. We can see a direct influence from the Gulf Of Mexico feeding directly into our low pressure. This will be a very intense and large storm. This will also probably be our longest duration event for the year.

My going thinking has been 4-8" for the area and then a switch over to a mix and possibly rain. I do think we switch back to snow as the CCB (Cold Conveyor Belt) swings through the area. The CCB is the back end of the "comma" head of the storm. As the storm pushes through, this will swing over the area. How much additional will that add? Well, like everything else with this storm, it depends.

I will say, the models have been all over the place with this very large and complex storm. My 4-8" is my best guess trying to make sense and from experience with these types of storms from prior years. Growing up in NJ, most of the large intense storms bring a period of a transition to a mix or rain. As the storm moves east of the area, we go back to snow till the end of the storm. While the model guidance has been less than stellar, I do hold out hope for the short range models, the HRRR and the RUC models which will be in their range later on tonight.

While my call is 4-8" with a transition, the confidence of that is low to medium. I think we are going to see some very impressive snowfall rates through the area. We have a storm that is going to dump between 1-2" of precipitation. The question is going to be figuring out, how much of that is snow, mix, rain. If it were all snow, we would be looking at 12"+ easily. Now, how fast do we transition? Do we transition? does it stay as sleet? freezing rain? rain? Do we go back to snow? What kind of precipitation rates do we have? These questions will all be answered starting in 10 hours. Until then, I am going with the 4-8" as my conservative estimate, with a strong feeling that the totals may end up higher than that.

So, while those are the accumulation questions, there will be other questions that will also need to be answered. I said that we are dealing with a very large and dynamic storm. Even if warm air moves in, and the surface temps get above freezing, if we have a period of very heavy precipitation, we can remain snow if the upper atmosphere is still below freezing. This will all have to be tracked as well with the storm. Obviously, if the rates are not that impressive, or the upper atmosphere and surface are above freezing, we will have rain. Speaking of dynamic......I fully expect there to be a good number of reports of thundersnow tomorrow. Maybe even as early as the early morning hours.

So, the specifics.

Snow moves in around midnight to 2am. It will snow very heavily in the early morning hours, with the possibility of thundersnow. Accumulations by the time we wake up will be 3-6". I expect to pick up another inch or two and then a transition to a mix will occur as the storm moves closer and some warmer air floods the upper atmosphere. I do think though we will remain sleet for a while. During the afternoon, precipitation may actually stop or become very drizzly. To the evening hours, I expect the CCB to intensify and move through dropping more intense snowfall before ending towards midnight. Exactly how much will depend on how the low pressure bombs out, and how much moisture can be thrown back over the area.

Anyways, those are my thoughts and concerns as of now. As always, I will be posting on facebook and twitter throughout the day and night.

Stay Safe!

Wednesday / Thursday Storm (Tuesday AM Update)

Overnight model runs have concluded and now I am looking forward towards today noon model runs. Last night, I explained on facebook where we were before the model runs. Overnight, the NAM was less amped, the GFS moved a bit west (but overall had a much better organization). The EURO was pretty steadfast on its track showing a front end thump of snow and then a transition to a mix and possibly rain. Today the models continued down the same roads and the NAM, GFS and Canadian models all bring in a period of sleet/mix/rain to CNJ.

With that, it has become more and more clear that our area will see some transition over to sleet/mix/rain etc. The projected track (on any of the models) will make it very difficult for us to remain all snow. Areas NW of 95 should do really well and will cash in with widespread areas of 12"+. Those areas would be places like Reading, the Lehigh Valley, NE PA and possibly NW NJ. I think areas down in CNJ are looking at a nice front end thump of snow 4-8" (possibly more) and then a transition over to sleet/mix and then possibly rain. There could also be a change back to all snow on the tail end. Coastal areas, there is a full moon expected as well Thursday, and with a developing low pressure coming up the coast, spells disaster for coastal flooding. 

In any case, a shift in the models by 50 miles east could make quite a difference. Same with a shift 50 miles west. With that, those are my general ideas. There will be more updates to come. We are still 36 hours away so there is some time for some wiggles. If you know anyone down in the NE Georgia, Central SC and NC areas, they will be receiving an epic ice storm. Make sure those down there are prepared and follow their latest forecasts down there. We still have people up this way without power from our storm last Wednesday. Also, areas not accustomed to snow could be in for some surprises as well (South Central VA, W NC etc). Also, DC looks to actually be in a pretty decent spot up our way for a pretty decent storm as well. 

More to come

A Look Ahead Into Wednesday / Thursday

With this clipper over for today, the next focus will be on a developing storm for the Wednesday - Thursday timeframe. The Canadian and EURO models have been hinting at a low pressure tracking from the SE coast, up to the Outer Banks and then east of Jersey to the "benchmark" (or just inside). The benchmark is a noted area, 40N 70W, where most of our significant snowstorms move through especially for New England). Also, this looks to be a much slower moving storm than we have had this year and will also effect a larger area.

The GFS has come around to the idea and has the storm, but has it further into the ocean and only scraping the East Coast. Tonight, the NAM also shows the storm, although we are at hour 84 on the 84 hour model (not the greatest at this range) but I am encouraged to see it there, and very amped up. There will obviously be some questions with track, intensity and so forth with this storm, but this is definitely one that has my attention. This will effect a large area, from the Gulf States to the Southeast to the Mid Atlantic through New England.

So, time to watch the continuity from run to run and see further cohesion in coming up with a track. There will be many updates coming, so please follow along on twitter and facebook!

February 5th Event (Monday PM Update)

As we wind down from our storm today, we can now turn out attention to the upcoming threat on Wednesday. Last week I made a post about a very active pattern unfolding over the area, and that seems to be the case. Yes, we have a lot of threats, and yes, we have some shots at snow. I will however, take it one storm at a time. I spoke of the change in any variable from a previous storm having an impact on storms following. Case in point, the next storm up, Wednesday.

Two days ago, this was looking like a washout. Now, with some fresh snowcover down, there is talk of a couple inches of snow and then a switch over to a mix and then to rain. Places now in NW NJ and NE PA could get a whole lot of snow and never transition over now. So, I am going to be curious to see how the models interpret this tonight and tomorrow. I have a sneaking suspicion that we could be in for a ice event, especially from Trenton north. 

As of now, Snow moves in late tomorrow night and will accumulate. Precipitation will transition over to a mix from south to north. It will make it to about rt 80 where north of there is out best bet to remain all snow. In addition, the mix will also change over to rain from south to north, and how far up that goes will be the question. This will be another quick moving storm, and will probably be out of here again by the late afternoon Wednesday. More to come on this storm. 

Another Surprise Today?

Not as likely, but temperatures are around 30 degrees. Temperatures that low, combined with a dew point in the mid teens will allow todays precipitation to start out as snow. Gradually, it will changeover to a mix and rain. A large majority of the precipitation for us in Central NJ will be rain. For areas north and west, it will be a different story. Snow and ice will rule the day and night. Areas in the Poconos, NW NJ and into NY and CT have a real mess on their hands. Areas even further north into Upstate NY and Northern New England can see up to a foot of snow! Not bad for late March.

Current Warnings (Pink)
Current Advisories (Blue)

Monday February 11, 2013 Morning Discussion

Some areas this morning had icy conditions. Areas from Central Jersey south have transitioned to all rain as temperatures have risen well above freezing. A frontal boundary is moving through with a low pressure to our west. With that setup, we get flooded with warmer air aloft and eventually down to the surface. Areas further north that have a substantial amount of snow will stay with the freezing rain a little longer due to the fact that your surface temperatures are colder due to the snow. Eventually, all areas will transition to plain rain.

A lot going on this week. First, for the period Wednesday and Thursday we have a potential coastal storm development. Most models have some sort of storm (although they get here through different tracks) for our area. The usual questions remain; track, intensity etc. Biggest question for me right now is surface temperatures. As it looks now, would more than likely be a mix to snow for Central Jersey and snow north and west. Coastal areas would be rain and some backside snows possibly. Hopefully over the next day we can nail this down.

Then to the weekend. This would be the period from Saturday Night through Sunday Night. We have another modeled storm that could be a bit more substantial. A lot to work out with this storm, and I am going to focus on the Wednesday - Thursday storm first. There is potential though for another coastal storm. We have had a number of storms affect our area during the Presidents weekend time frame, and this could be another case.

New England Historic Storm Taking Shape

If there is one thing that is pretty certain here, is that New England is going to get smoked. These estimates of 24-30" of snow are realistic. This is going to be an old fashioned, New England blizzard. For the rest of us, from NYC south, the uncertainty remains king. We are dealing with two separate low pressures. One, a disturbance diving out of Canada towards the East Coast. The other, a low pressure in the Gulf States. These two low pressures will phase, or merge, along the East Coast and move ENE around the "benchmark"

EDIT- I have mentioned the "benchmark" on several posts, but I have probably not done a good job explaining why this is important. The "benchmark" is located at 40N and 70W and the significance is that a large majority of winter storms pass over this area bringing the perfect balance of distance to bring the biggest storms.

So, the questions remain where exactly these two low pressures phase, how phased the evolving storm can intensify, speed of travel and track of the storm. Each model is still showing some different outcomes based on these variables. Each model is also able to pick up on subtle characteristics that are making the forecast very difficult. Overnight, the NAM model had zero snow for Philly. The GFS showed a couple inches for Philly and the Euro was like 6" for Philly. Whats more mind boggling is while Boston is looking at 30", NYC could very well hit 12" of snow, while Philly sits at zero. This is the type of spread we have. Any earlier phase, we could be looking at substantial snows. Any later, or a further east track, we will be looking at showers with next to nothing.

For now, I am going with snow starting very early tomorrow morning (5- 7 am). Late morning we switch to mixed precipitation and rain. Late afternoon we switch back to snow and may get some period of moderate snows. I think from 195 north to NYC, 3-6" can be expected while areas from 195 south to Philly can expect 1-3". This is based on my current thoughts, but confidence is still low on this. By tonight I will issue a final. Places in NW NJ and the Lower Hudson Valley 8-12" can be expected while areas to the east from I87 - I91  12-20" and then from I91-East Coast 20-30".

Please remember for those areas looking to get walloped that this will be a rapidly intensifying storm and the winds will be whipping. There is also a higher than normal chance for thundersnow. Snowfall rates will easily make 1-3"/hour in many locations, if not more. This will be a very intense and dangerous storm.

Another Close Shot

A warm front will be moving into the area tomorrow and bringing another round of precipitation. We still have an arctic airmass in place which will give way to much milder temperatures (Tuesday, Wednesday). As precipitation comes in, the upper atmosphere will warm, but since cold air is heavier than warm air, the cold air at the surface will take a little bit longer to warm. This process, known as warm ait advection will possibly lead to an icy situation Monday. The timing and extent to which how long it takes the cold air to retreat will all be determining how long icy conditions could stay around.

Areas to the south will have little to no icy time while areas to the north will be a different story. Typically, NW NJ and the Pocono gets quite icy during these setups. Areas further south from Philly to Trenton tend to switch over pretty quickly. Between Trenton and the before-mentioned NW NJ and Pocono region, that will be where the real battle sets up for how long it takes to switch over to all rain. Precipitation makes it in for the morning hours. Many areas will start as snow and then switch over to ice and then rain. Areas will start from south to north.

After this bout with weather, we will have a nice thaw coming for Tuesday and Wednesday. The pattern will reload and it will return cold towards the end of the week.

The Week Ahead

First round of rain moved through last night. There were some reports of sleet in NW NJ. Another round of precipitation moves in tonight, and areas just NW of our area will be looking at wintry precipitation. The Lehigh Valley and Poconos as well as NW NJ could see frozen precipitation with this. Areas that see snow could get a 2-4" snowfall, while other areas that stay frozen could receive a minor to moderate ice event. Precipitation moves out tomorrow morning.

Next time frame I will be looking at is towards the end of the week around the late Thursday to Saturday time frame. Models are showing a storm moving off the SE coast. Usually this would mean little to us up here, but the general trend this winter has been each model run coming further NW. So, its something I will keep my eye on.

Colder temperatures will be sticking around for a while. Next week looks to get really cold :)