Monday, January 11, 2016

Monday Morning Weather Discussion: Studying Weekend Trends

Good morning. I left you guys with the idea that we had to keep our eye on storm developments over the next several weeks. In particular I discussed a clipper system on Tuesday night that will bring snow to northeastern NE and the potential for a far bigger storm this weekend. Today's post will evaluate trends from the weekend for those two events.

Starting off, the clipper looks to be on track. I expect a coating to an inch of snow for most of New England with several inches for Central and Northeastern Maine. For the suburbs of the tristate area, we should see some flakes and maybe a coating for some counties. 

Here is the updated model projection of this clipper system..



This will really intensify as it gets into the Gulf of Maine/Nova Scotia. That is why I think parts of Maine see over 6 inches with this.

Moving on, we now turn our attention back to the bigger storm threat for this weekend. Around the middle to end of last week I picked up on this signal from the model ensembles..



This was a great looking model projection for a east coast snowstorm and I highlighted the key ingredients above. So how has this trended?...


The new image is the same exact model same exact time but a run that is as of this morning. It actually looks very similar but there are differences. If you look closely, you will see one big change which is the slope and position of the ridge or rising lines out west. Also, you will notice the northern energy that is driving towards North Dakota is stronger. This is not the best trend and here is why...

The ridge in newer model runs is more sloped to the northwest. This allows that diving piece of energy to enter the country more to the west. As it does this it is able to interact with the second piece of energy over Texas quicker. This causes a storm to develop earlier. As the storm develops earlier it naturally develops more inland. This develops a primary surface low to our west. NOT GOOD. 

Now the second issue. Take a look at the vortex feature north of Maine. That could be our saving grace if that ends up being further south. This vortex would help lock in cold air. Thus, even though the storm develops to the west it runs into the cold air sooner and transfers its energy to the coast sooner. That feature is too far north given the fact the ridge out west is too sloped off shore. 

Now this is the GFS Ensemble. How about the European ensemble does it have same trend?


Looking above you can see the old european ensemble from Friday on the left, new on the right. Its hard to see the differences as much in this image but they are there although not as intense as the GFS. The energy does interact sooner in the new run (you can tell by slow of the blue in the center) and the vortex is more north in the new run over eastern Canada. Not a good trend here either. This has me concerned because this is a very powerful weather model, the best may I add.

So whats the bottom line?

  • Weekend trends have favored a storm that develops earlier and inland.
  • Storm will later redevelop off the coast
  • This means the Mid-Atlantic region is not in a good area for snow
  • New England still looks ok to me.  
  • Not making a preliminary prediction on this until at least tomorrow night- a lot can still change!

Now here is the silver lining. We do have this storm running into high pressure still. This means it has to redevelop towards the coast(storms dont plow through high pressure, take path of least resistance). If this HP is stronger and more south then Mid-Atlantic can still be in the game. I can not say that at this time however. Below is a diagram I drew to describe this storm..

If I had to make a prediction at this time, this makes the most sense to me. It would be snow for interior New England. However, I am not making a prediction yet. The goal of this post is just to lay out the factors and where they are heading. This is still 5-6 days out and things can change. By tomorrow night I will put together a preliminary prediction. 

So does the same record play? Will my snowfall forecast go up in flames this year? I really do not know, the pattern I expected is there at 16000 ft (500mb)but as you can see that doesn't guarantee anything. At the same time, I still can not pull away form my ideas due to this pattern. If we get through this whole month however with no substantial snow then I will be seriously on the ropes. 


Lets not jump to conclusions yet ;-). Hopefully how this movie ends is how this winter ends. 

Stay tuned, this is a volatile situation for the weekend and sometimes our biggest storms have always been the ones that trended well at the last second. I might have an update tonight.

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