Wednesday, December 9, 2015

Wednesday Morning Weather Update: Some Encouraging Signs Developing

Good morning everyone. As I continue to monitor this weather pattern I am starting to see signs up hope for winter weather lovers. Although I still do not expect a big pattern change till end of this month/early January there are some encouraging signals I am watching develop.

Going back to the stratosphere (way up in the atmosphere, higher than commercial jets), models continue to suggest the polar vortex will come under stress as heating is starting to occur...



Looking above you can see what the atmosphere looking like at the 10-hpa pressure level or in other words way high up at the upper limits of the stratosphere. This image is 168 hours out from now. The colors show the temperature around the northern hemisphere. I want you to notice the area I circled in red. This represents heating that is occurring in the stratosphere. This heating puts stress on the polar vortex and the result is it causes it to migrate off the center of its axis shown by the red X. This heating actually originates at lower altitudes in the troposphere and as it travels to the upper limits of the atmosphere, it can have a drastic effect on our weather conditions especially 3 weeks later.

I will note this is not a major warming event and we are still just looking at model projections. However, one of the reasons we have been seeing such warm weather is because the lack of high pressure or a negative Arctic Oscillation at the pole. The polar vortex under stress can change this and consequently eventually cause a pattern change for the east.  To illustrate further, here are projections on the Arctic Oscillation. Notice there are now possible negative outcomes...




So moving on to the weather models, things do stay tranquil though the weekend. Our next shot at unsettled weather comes early next week as a low pressure system should pass to our west..


It is in the wake of this storm system that things could start to get interesting from the 17th through Xmas Eve as there are signs cold are could start pressing as shown below..



IF we get everything aligned property I would not be surprised if it snows around the 19th of the month up in New England and possibly further south as a storm system could ride the boundary of warm and cold air as I indicated above. 

This is still not our main pattern change but at least we got some action on the table here! Below you can see the surface map  of warm and cold air clashing..


Sure this could develop well inland but my point is it all depends on how much this cold air presses east.  It is something that bears watching as we head towards the Xmas holiday. 

As a reminder here is what I projected for the January weather pattern back in October in my winter outlook..



Compared to December..


You can see my point that this was supposed to be a winter that slowly evolved. Now we sit back and see what verifies.

Thanks for reading.  I'll cut a video this week w more detail l.

2 comments:

  1. Hey Willy, I'm far from an expert on stratospheric convection and advection, but it looks to me like there's a whole lot of heavy Siberian and Alaskan snowpack between that warming area and say the 75th parallel. Another interesting thing to ponder (although right now it may be more of a footnote) is that convection between the troposphere and stratosphere is at the heart of the global warming matter. Not sure that I want to totally commit on this question yet, but there is supposed ly a lot of research indicating that historical changes in the tropo including human-made gasses is reducing outward radiation over time, thus increasing heat content within the troposphere. Although, admittedly, this may be happening on a scale that affects long-term average temps but isn't immediately relevant to short and medium term weather patterns. For now, looks like the AO is due for a dip in the next week or so, but as to whether a weakened polar vortex will defeat the Nino heat and bring us another old-fashioned winter is 'up in the air', both literally and figuratively! Last year, of course, saw a strongly positive AO most of the winter -- has the dynamic behind that changed? We shall see, interesting as always. Jim G

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    1. Hey Jim,

      Thats true all that snow pack is reflecting back the solar radiation into the upper atmosphere. This is supposed to contribute to stratospheric warming per Judah Cohens research. It is going to take time but I really do beleive this pattern is starting to change. We might see hints of this in about 7 days then by the time we get to January its game on. Issue I have with man made gases in particular co2 is that c02 represents only 0.04 percent of the atmosphere. The atmosphere is mostly water vapor. So I think we need to take all climate factors into account like the sun, oceans, volcanoes, and greenhouse gasses. From there maybe someone could develop an equation to figure all this out. Step one is agreeing on the actual temperature trends first tho and that debate is still raging. This nino is raging but notice where the convection is, it is def more westward which I like to see. Also, last year the pacific warm pool really just overpowered the pattern which did have an influence on the AO. This year I think that the snow cover argument along with some other research other have done such as @almarinaro suggest this year could be more favorable.

      Time will tell! I am just looking forward to watching this evolve. Thanks for reading.

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