If you have been following with us on our Facebook page we have been talking about having to watch the time frame of Thanksgiving for the next potential storm system that could bring snowfall to the Northeast region.. We first started talking about this on Oct 29th during the historical Northeast Snow Storm. We are going to take a look at the teleconnections first and then we will look at the guidance.
The first thing we are going to look at it the MJO or the Madden Julian Oscillation.
According to the image above we are currently in Phase 8. We mentioned before that if this was December Phase 8 is where you would want the MJO to be if you wanted a colder pattern and snow potential. However since it is in November instead this means that after this current transient cold shot we are going to moderate in temperatures once again but nothing like this last moderation we saw. Keep in mind this is November and keep in mind that we have been talking about a step down pattern. So lets look at phase 8 of the MJO.
As you can see we see higher height anomalies along the east into the Northeast.
Now this is the MJO forecast and you can see that the MJO is forecasted to go from Phase 8 to Phase 1 & 2. So let’s now look at those phases and see what they indicate..
So now we see that phase 1 and two represents that step down pattern into a colder weather pattern. Now we will look at the NAO.PNA & AO.
First is the North Atlantic Oscillation and you can see that it is starting to tank during this time period. This is in favor of colder air penetrating into the region..
The Arctic Oscillation is a bit more divided with some members tanking the AO while other members are keeping the AO positive. It is important to note at this time that there are presently more members showing the AO going negative then there were a couple days ago & we think the negative trend is correct based on what the PNA is projected to do.
As you can see the PNA is projected to be rising to positive during this time period. So this would argue that a trough should be building in the east with ridging building in the west. So as we can see the teleconnections are favoring a return to colder weather.
Now lets look at the guidance to see if they are showing any type of storm for this time frame.
We first look at the UKMET and we can see that the UKMET @ 12 Z today does indeed show a storm system across the southeast. This model only goes out to 144 hours.
We move on to the GFS and that is the image on the left. We want you to notice that the GFS is well NE at 144 hours. However the image on the right is the 12 Z Nogaps which is the most progressive biased model there is and it shows a more southwest and slower solution. This points to the GFS at being a too fast progressive outlier!
Next up is the ECM. The ECM shows a storm system developing over the Southwest and then moving to a position off the New Jersey coast at 150 hours.
Now. be very careful here because there are some “pro mets” claiming that the ECM is not showing snow in its solution but we beg to differ.
The image above is a “3” hr. total of snowfall that occurs from 147 hours out to 150 hours out based off the 12 Z ECM. So folks the model does INDEED show SNOW. In the big cities? No.
Another thing that it is important to note is that the ECM last night was showing a solution with the low pressure near Buffalo NY & even in that solution the same areas above seen snowfall.
The truth of the matter is the 12 Z ECM is actually south and east of its 00z run last night and is actually colder with temperatures basically in the 30s at 18 Z Wednesday!
Now lets look at the ensemble means of the ECM..
A couple things on the image here. First you see a slightly more progressive system & second you see a weaker system. This is to be expected because it is an ensemble means made up of about 50 members-so it smooth’s it down.
The other thing to note is if you look at the 850 MB level temperatures it is actually colder at the 850 mb level then the operational.
So…what you can see is that the models do indeed show a potential for a storm in this time frame. The teleconnection’s also support a return to a colder pattern.
At this present time the only thing we are suggesting is that this time period needs to be watched. It is possible that because the models are now beginning to recognize the change to occur that they could be under estimating the high pressure (cold air source) to the NW of the storm.
At this time there is the potential that some areas may indeed end up with a white thanksgiving..but the details as to what locations and amounts etc. are not going to be clear at a 7 day time lead. The key word here is potential!
Stay tuned as we continue to monitor this potential!
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