The Next Threat Examined!

The next potential threat is on the table during the time period of Jan 18-19th and this is about 7 days out that we are referencing.

First of all as is important with any storm threat is the pattern and to look at what is currently in place at the time of this particular time frame.

Current MJO is in phase 5. As you can see from the images below the MJO progression is expected to go into phases 7-8 which would be supportive of an East Coast Storm.

Now you may be reading in places across the internet that the NAO is expected to go positive. This is not exactly true.

The NAO never really gets above the neutral range. So while it is true that its not negative its not actually what would be considered positive..which in the case of this time period is a good thing. A neutral NAO means if there is cold air nearby it would be able to bleed into the mid Atlantic to the NE..just not as far south as would be the case with a strong negative NAO.

The Arctic Oscillation at this time is still expected to be negative which means that cold air would be available to tap into as well. Finally there is one more teleconnection to look at.

The PNA, and as you can see the PNA is expected to go positive over the next 7 days. So the teleconnections in place or the pattern if you will are a neutral NAO, + PNA & a –AO.

So the pattern would be conducive to a storm that would probably end up coming more inland then if the NAO was negative.

So lets look at the ECM computer model. The reason we are looking at this model is because this model I believe has a better handle on the overall pattern as discussed above and this model supports the pattern discussed above.

Here we see the ECM with another Miller B which develops off the coast of North Carolina. You can see that the 850 line is actually south of NJ. So you may be reading that this model is not cold enough to support frozen but that simply is not true because if the 850s are cold ..generally look for the surface temps to be in the 30s which would be supportive of frozen. Why is this the case?

Lets look at the same image but i have drawn on it the reason why.

This is what we refer to as the wedge of cold air. Or Cold air damming. If you look at the image before you can see why this occurs.

Strong high pressure but this strong high pressure with cold air starts to pull away off towards the North and east..however it would leave a wedging of cold air trapped against the mountains. A wedge of cold air at the surface and 850s @ 0 or below would be supportive of snow! So the 12 Z ECM would be another Heavy Snow Event on the operational ECM.

The ensembles paint a slightly different picture..

The low is more inland, however, 850s are still supportive of frozen precipitation at that frame from about Central Jersey North and west thru PA and then NE..but with a more inland placing of the low pressure ..this probably takes a track across the Appalachians and off and over the SNJ coast and then NNE from there.

So with the ECM & its means best supportive of the pattern in place & looking at the pattern that is expected to be in place..We here at R.W.S have decided to go and make a rough scenario map for this particular time frame.

It should be noted that this storm has the potential to have alot of moisture associated with it. Stay tuned to more updates on this particular system!