Perhaps A Big Ticket Event Up Coming?

Currently the pattern that we are in right now is a pattern where we have a Negative NAO..We also have a Positive PNA.

This pattern is causing the area to experience colder then normal temperatures. This pattern also just caused portions of the region to receive upwards of 4-8 inches of snow during what is officially considered spring. With the below normal temperatures and the snowfall , one could say that we been in a pattern that is more representative of winter then actual spring..and they would be correct with that thinking.

Well, we know this pattern can not last forever and if we look at the NAO above and the PNA ..you can see that over the next 8-10 days that this pattern should be flipping from a negative NAO to a positive and the PNA from negative to Positive. When this generally happens we see what is considered a large scale weather system that can potentially become a big precipitation producer. This is generally called the Heather Archambault signal.

ITS ALSO BEEN NOTED BY HEATHER
ARCHAMBAULT THAT LARGE PRECIPITATION EVENTS OFTEN OCCUR DURING
PATTERN CHANGE TIME

So..we are going to look to the guidance to see if the models are indeed suggesting that a system has the potential to be a big ticket event in the next 8-10 days and particularly around that time frame of the Heather A signal.

We are going to look at the 12 Z guidance and there are only three models that are considered main guidance that actually go out far enough to cover that time frame. Those would be the GFS/GGEM & ECM.

As you can see we are looking at the time frame of 168 hrs to 240 hours out and the GFS does have one system off the east coast at 168 hrs but you also can see that it has another larger system forming over the southeast back into TX.

Lets go to the GGEM @ 12 Z..

At 180 hours out the GGEM has a system also that stretches from off the SE coast to the SW back towards TX..however..this is the furthest the model goes and we do not want to speculate as to what the GGEM does with this system at this time.  One could however say looking at the stream lines that the system would more then likely just head out into the At;antic.

So we have covered two of the three models and so far even though the teleconnections are showing the Heather A signal..neither model is showing anything that would really present a large weather system or precipitation maker along the east coast. So this lets us to consider whether the teleconnections are wrong or the guidance is wrong? Well lets look at the ECM from 12 Z and see if the model is representing the connections better then the above guidance.

Here we see a system down over the Southeast that comes out of TX. By 168 hours it already has a LARGE precipitation shield stretching from Southern PA , west south west into Ark and then across all the southeast from Fl westward to Tx..

By 192 hours this system is then off the NE coast with 850s below freezing with the exception of along the coast close to land. Moderate precipitation across the region still at 192 hours and it is not until 204 hours that the precipitation moves out of the State of PA (all but NE PA) . So the ECM definitely has a large scale precipitation maker at the present time on its 12 Z model. However..it is the only model showing this potential at this time (12Z).

As of the latest 18 Z guidance which is only the GFS..we notice that now the GFS has made some changes.

Now the GFS looks pretty similar to the 12 Z ECM & is in agreement with the ECM & also now suggests that there will be the potential for a big time ticket event.

Since this is long range it is way to early to even begin to speculate on what type of weather this system will bring to the area. Temperatures as currently modeled could indicate a heavy wet snow for far interior areas and heavy rain for the coastal areas.

We will continue to monitor this and see if the region can end up getting one final snow storm before the pattern changes.