Real Wx Services is issuing a Level 1 Alert to be “ On Guard” in reference to the inverted trough situation that will be developing over the next 24 hrs. This alert basically covers from SE PA into NE PA into NYC extending up into Southern New England. At this point and time it is too early to determine exactly where the heaviest snow bands will set up. We are monitoring globals as well as mesoscale models as the Meso models should have a better handle on these features then the globals. For now we will maintain the map we created back on the 4th but will probably make some minor adjustments later in the afternoon.
A brief look at guidance from yesterday evening and late night.
00 Z NAM above..
06z NAM above
Meso Models NMM & AWR
Finally the RGEM which is the canadian Short term high res model.
As you can pretty much see these models above develop the inverted trough feature across Eastern PA into NE to NYC and NJ and then start to move it NE there after into SNE . With the exception of the NAM these high res models only go out to 48 hrs.
It is almost impossible to determine exact amounts in this type of feature until closer to the event which is why we will be revising the map later today. For now we will continue to stick with the preliminary map and that is below. Snow should start to arrive towards friday morning across the eastern regions and be pretty much over with by friday night and saturday further to the north.
Remember this will be revised later today but it will not be too far off from that general portrayal.
Now moving on to the 2nd part of this update and that would refer to the 2nd storm that we have been monitoring and anticipating as well.
This second threat covers the time period of the 11-13th. Global models have been relatively back and forth with this system anywhere from a OTS solution to a solution that brings over a foot of snow to the coast again (GFS) to a system that has a primary into Ohio and a Secondary develop along the coast.
With so much flip flopping of guidance how can anyone make any sense out of what is suppose to happen and occur?
That is where knowing the pattern comes in handy. You know with the blocking that is currently in place over North Central Canada that there is going to be cold to very cold air across the central US into the Northeast & Mid Atlantic. So what this tells you is that because of the strong confluence in those regions pushing southwards ..unless the pattern would change…even if this is a primary heading to Ohio it would have to redevelop somewhere along the coast..because it is simply not possible for that primary to penetrate thru the block. The block would have to lift up and out and weaken for it to cut too far N & W .
So knowing the pattern takes the emotions out of anything cutting to far west. So we are left with only two other choices which would be a coastal Miller A…or a Coastal that goes OTS. These are the only options with a pattern in place with a –NAO –AO.
So lets look at the different guidance and what it is showing starting with the model that normally would be the best ..the ECM.
Well we see the ECM actually slides this out to sea and at 168 hrs (not posted) actually tries to create a inverted trough back towards the Jersey shore region.
UKMET @ 144..Hmm well that certainly looks further west then the ECM & it also stands out to the ECM as a red flag! UKMET only goes out to 144 so we do not want to speculate where it would go but it pretty much at that point looks like a power house.
GGEM is up next…
Interestingly enough the GGEM is actually a more progressive bias and we see that the GGEM is actually somewhat more to the west then the 00Z GFS which is following this.
So there you have the GFS at 144 hrs and it to is also more west then the ECM. Matter of fact when you look at all other guidance ..the ECM is a clear outlier. Two of these models are progressive (GGEM & GFS) but are further west..and the UKMET which is also progressive beyond 72 is also more west then the ECM.
However, once again it gets interesting as we earlier today in the chatroom at the forum thru out the red flag that is probably the biggest red flag of all towards the ECM and even the GFS, along with the UK.
Once again you are looking at the NOGAPS which at day 6 only ranks one notch below the ECM on overall verification. Does that tell you how bad the ECM has become?
However, the one thing that the NOGAPS has been is consistent with showing this as a Major Storm for the East Coast and its also been consistent with the primary to the Ohio area and redeveloping along the coast.
Now, there is some thinking, currently, from inside R.W.S that this could actually be more of a coastal hugger to inland runner. At this point and time that is more of a concern then the solution sliding out to sea.
So essentially look for the guidance such as the GFS perhaps today or in the near future to trend more west..the ECM to trend well west and north with this system.
This second system remains very well a threat on the table for the time frame of the 11-13th so R..W.S is issuing a level one for the Mid Atlantic into the Northeast for the potential of a Significant East Coast storm!
Stay tuned for details on both these events later today!
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