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Another Displacement Of The Polar Vortex Looks Possible & This Could Mean BRUTAL Cold!

It is kind of rare that I dive into the longer range data in my blogs. Part of the reason is the patterns need to be rock solid for me to believe anything the medium range data shows. If I can justify the long term computer model solutions with sound meteorology, then I will dive in to these discussions. The bottom line is that I think another displacement of the polar vortex will occur in the next 2 weeks and I want to start talking about the major impacts it could have here.


Weather Pattern Potentially Breaks Down Into Another Displacement Of The Polar Vortex


A couple of weeks ago, every person in the country was introduced to the term "polar vortex". The word was misused more by media than I could have imagined. I was watching images from Niagara Falls when two cable TV anchors said "last week's" polar vortex caused part of the American side of Niagara Falls to freeze. With all the misunderstandings, I want to explain quickly what this whole polar vortex means.


The polar vortex resides over the North Pole and is obviously surrounded by the coldest air in the northern hemisphere. At times the polar vortex can get wobbled and if that occurs, it can move southward to the mid latitudes where we live in a process called a "displacement of the polar vortex". When the polar vortex is displaced, it drags the cold air from the North Pole where ever it goes. The cold is not a polar vortex, but the displacement of the polar vortex is what causes the brutal cold.


Understanding it is the displacement of the polar vortex that is important, let's start to look at the pattern. Right now we have a blocking high pressure along the west coast of the US. Quite frankly it has been there nearly all winter and there is zero indication that it will move. This creates a jetstream that comes directly out of northern Canada and the north pole. Right now, you can see how the jet stream is pulling another low from northern Canada right now.


Gfs 500 mb 1


As we move into early next week, we see the blocking high pressure still stuck over the western US and now this is becoming a problem. If you notice, the original low over northern Canada is now dominating the Great Lakes region and there is a new low at the very top of the image below. This constant flow from northern Canada is starting to tug the polar vortex toward the US and now for the first time since the major cold 10 days ago, we actually see it moving toward our part of the world.


Gfs 500 mb 2


By Friday, the block in the western US has become even stronger and we continue to see the jetstream coming out of the north pole. This constant tug on the polar vortex has created a cascade effect that allows the polar vortex to dive southward toward the US. The low over southern Canada is the polar vortex.


Gfs 500 mb 3


By Saturday of next week, we have a full on "displacement of the polar vortex". The polar vortex that normally resides over the north pole is now sitting north of the Great Lakes. This means the GFS is showing a full displacement of the polar vortex which means it will pull the air from the North Pole into the US.


Gfs 500 mb 4


The question is then "is this data reliable"? Well let's look at the EURO computer for next weekend too and what you will notice is a SPOT ON match!


EURO 500 mb 1


Simply put, this is not good. The EURO and GFS computer models show the exact same thing.



How Cold Are We Talking About?


The exact tragectory of this cold air is going to be very uncertain this far out. What that means is that some of the data will likely drive it east in the coming days while others will allow it to flow down the Rockies and blast our area. I think a direct hit for us is entirely possible. The GFS shows temperatures that are nearly 40 degrees below normal in about 8 - 10 days in our area.


Gfs temperature anomoly 1


How cold is 40 degrees below normal? Well the GFS takes us in the 5 to 10 BELOW ZERO range by a week from Monday!!!


Gfs temperature 1


As you would expect, the EURO is showing something very similar. Notice the wind chill values of 60 BELOW ZERO a week from Sunday over the north tier of the US. This is absolutely brutal stuff.


EURO 850 Temp 2


If that cold just stayed in the northern US, then we would have a problem but the EURO shows it is on a line to take it directly into our area.


EURO 850 Temp



My Thoughts On Another Displacement Of The Polar Vortex & Impacts Here...


The weather pattern is dominated by a blocking pattern in the western US. This block is responsible for the dry west coast and it has also allowed a constant flow from northern Canada into the US. Inevitably, this pattern will cause a wobble to the polar vortex and allow it to move. The data strongly suggests a displacement of the polar vortex will occur late next week and I think considering the jet stream pattern, the data is accurate.


The question is where will the polar vortex move.. toward the east coast of the US or right into the heart of the US? This part is not entirely clear. In either scenario, I see a very cold next 7 - 10 days with only one or two days with temperatures above normal. If the polar vortex moves toward the Great Lakes, then the data suggests temperatures will fall at least into the single digits, but I wouldn't rule out sub-zero readings again. Statistically speaking, it seems unlikely to have decadal cold twice in the same month but it appears a real possibility. I think we will at least get a glancing shot of frigid air late next week and early the following, but at worst case it could be BRUTAL and really bad. For what it is worth, the Climate Prediction Center agrees and in their 8 - 14 day forecast has us at a 70% - 80% chance of below normal temperatures.


CPC 8 - 14


This is potentially a major story for our area and I will be watching it VERY closely in the coming days.




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What temps are we looking at in West TN (Crockett County, specifically)??

So our "once every 10 years" type of cold, has turned into twice in the last three weeks.....

I love you Marc! (OK, that sounds too creepy lol) What I mean is that I enjoy reading your blog so much and learning about meteorology in general! Thanks for the dedication you put into this.

jim, keep in mind that I am not saying we will go subzero yet. If that doesn't happen then this is not once in a decade cold.

Israel, LOL! I appreciate you support on the blog. :)

Kimberly, I am not willing to say how cold yet other than it will be very cold.

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