Crushed by Confluence Or Further North?

After the extremely mild air of the past 72 hrs we now have a cold front that is working across the area and this cold front is going to usher in some colder air and very windy conditions. Winds could gust as high as 50 MPH or higher across the region. We will have some strong CAA or Cold Air Advection with these winds so tomorrow will be a much colder day then today was. There after all eyes turn to a pair of low pressure systems that will be approaching from the west. The question becomes how far north do these systems track? Or how far south? The further north they track the more mild air will feed into the region and any precipitation would fall in the liquid form. The further south they track …precipitation would be more in the wintery form.

Latest guidance has been suggesting a northern track for part 1 or wave #1 and a southern track for wave # 2.

Lets looks at the guidance…

AS you can see pretty much all guidance is showing a track to the north with wave # 1 which would suggest the possibility of snow going over to rain with the first area of precipitation. Matter of fact the GFS/ECM have temperatures reaching the 50-60 degree range on monday.

That brings us to wave # 2 ..

12 Z GGEM would show a decent snow event across parts of the region. It must be noted that the GGEM is the furthest north solution.

ECM brings moisture from the 2nd wave into the region but the furthest north it gets is about the ABE region with 1-2 inches of snow. It essentially has no surface reflection as it gets sheared out by the strong confluence.

GFS also takes the southern track with the area of low pressure and pretty much the same story as the ECM.

As you can see the 12 Z Nogaps basically is the same story as the rest of the guidance with the system further to the south.

The question becomes how far south does the cold air press into the region? Is it strong enough that it would suppress the system that far to the south…or does the boundary set up further to the north?

All guidance suggests that it sets up to the south..however..one has to ask themselves if the first storm goes north…and the second one is only about 6 hrs behind the first one ending..what is going to cause the 2nd wave to be suppressed south?

Well..long story short guidance is suggesting that the Polar Vortex is going to be dropping southwards into the Northeast and this confluence then suppresses the system south.

This very well could be the case but teleconnection wise would support a further north track to the system and current thinking is that the low pressure should move right along the PA/ MD border and then move east off the coast and NE from there.

So current thinking would be that the heaviest precipitation would be over Central  PA to East Central PA into Central and southern NJ and points to the south…with lighter precipitation from there.. However..its too early to say what form that precipitation will take..it all depends on where that boundary sets up. If you are on the north side it would be frozen and on the south side it would be in the liquid variety.

We will continue to monitor this situation!