Pattern, Pattern, Pattern–Pattern Change Coming?

This has been the question since the beginning of November. We all remember being told that the pattern was going to change and the pattern was going to change to a colder and snowier pattern starting in Mid November. When that did not happen we were told it was going to occur in Mid December. When that did not happen we were told it was going to occur in Mid January! Here we are at January 23rd and we still have not had a pattern change to one that is locked in sustained cold and snowier weather.

Matter of fact lets look at some departures. Overall October snowfall counts towards the season but lets assume that this snowfall did not occur and we just look at the Winter beginning with Dec 1st..

ABE 3.4 inches this is 9 inches below normal..

PHL. 2.5 this is 5.5 below normal

NYC 4.3 this is an inch below normal

Newark NJ 3.7 which is 2.2 below normal

Boston MA 6.6 which is 3.5 below normal..

Now lets look where we have been as far as temperature departures..

November 2011

December 2011

First 23 days of January..

The moral of the story since at least November 1st has been above normal temperatures.

Now is there a reason for this? Well, there are a couple reasons…

First one is the MJO. The MJO has not been able to get into any favorable phases. When it does not get into a favorable phase it ends up extremely difficult to get any type of teleconnections in place for colder and snowier weather. When you have convection near the date line this helps to bring about a + PNA ..We have not seen that because the MJO has been in phases 3-6 all winter long..

So where is the MJO currently?

Phase 5 of the MJO. Now we are not going to look at MJO forecasts because they have not been verifying well but we will look at the 500 mb anomalies for Phases 5 and 6 for January and February to see if they indicate a turn towards colder and snowier..

The above is January Phase 5 and 6. Certainly not reflective of a cold pattern..But what about Feb?

So what we notice is that we do not get any help from the MJO in phase 5 or 6 in January or February.

So now we have to look to the teleconnections..

Remember the following: A negative NAO represents colder weather in the east. A positive PNA represents ridging in the west and troughing in the east. A – Ao represents colder air discharging south into the USA..A – EPO also represents colder air discharging into the USA… Keep that in mind as we look at the teleconnections. We are using the ensemble means from 12 Z of the GFS/ECM..

GFS AO

GFS EPO

GFS NAO

Now these are the first three teleconnections off the GFS ensemble means which are the AO & EPO and the NAO.

Notice the AO goes positive? The EPO is positive (till the very end) and the NAO never goes negative but at the most neutral negative to neutral positive. These three signals are not cold weather signals..

Finally the PNA. Now this is a signal that would put the trough on the east and the ridge on the west once we are further out in the models range.

The problem is that the GFS ensembles has been trying to bring the PNA positive before..and it has failed to happen.

Now lets look at the ECM teleconnections..

AO is going from negative to slightly positive and then stays at neutral negative to neutral positive thru the next 240 hours. This would represent cold air having a very difficult time sinking southwards.

EPO ..completely positive. Again this is not another cold signal on the guidance.

PNA mainly negative but at times flirts with positive. This would indicate more in the way of transient troughs when it is positive… transient colder air associated with those troughs.

Finally the NAO which is shown to be in the positive to neutral negative and then neutral positive range.

Outside the PNA signal on the GFS ensemble means there is NOTHING to indicate that we are heading into a pattern change to more cold and more snowy sustained weather.

Rather the signals indicate what we have been dealing with all winter long. And now lets take a look at the real MCCOY of a reason as to WHY we have been so warm this winter!

To do this we are going to once again use the ECM ensemble means but each image has been illustrated on to try and make it easier for the readers to understand..

Now, wait , wait but I thought the GFS shows a pattern change occurring? Does the GFS agree with the above?

So you can see that on both the GFS and the ECM thru at least the next 10 days which take us into the first week of February we continue to deal with the pattern we have had in place. That is the Alaskan Vortex.

Until that feature is GONE or retrogrades west…and ridging builds into that region ..we will continue with the theme of above normal temperatures with transient shots of colder air.

What about snowstorms? Until the pattern would change…we will have to depend on perfect timing of shortwaves with the colder air time periods.

If anyone is trying to say that this has not been a sustained warm pattern overall…they are either kidding themselves or just trying to gain popularity!

We will not look beyond 10 days because that would depend solely on the Global Forecasting System which changes every 6 hrs.…