TECH DISCUSSION: Abrupt Switch From +/-AO/NAO, Weak Polar Vortex... What's The Cause & What's Ahead?
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- เผยแพร่เมื่อ 27 ก.ย. 2024
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#polarvortex #maddenjulianoscillation #northatlanticoscillation
It's as if Storm Babet took revenge on the south instead of the north almost 1 year later.
thanks Mark, you were grand explained that well :)
cool stuff Mark :)
I think one of the most important things to keep in mind when looking at the PV is that there is a stratospheric PV (that forms during winter) and a tropospheric PV under that is there year around.
The state of the strato. PV can be monitored looking at height anomaly charts at high altitude (10,30,50 mb down to the lower strato.), BUT the AO charts (like the gfs one 34:10) show the state and forecast of the PV at tropospheric level underneath, which is ALWAYS what determines if europe could see colder or warmer weather, because its the tropo. PV that dictates what the weather does close to ground level.
During winter if the whole PV is strong (in a normal state) it can be viewed as a column rotating from almost the ground up to the highest strato. levels and so the both parts of the PV seem fused as one really high column. In this case what you see are a centered clean circular and cold stratospheric temps over the pole and a positive AO.
Now the relationships between the 2 levels of the PV are complicated, but to make it as simple as possible, there are 2 things that can disturb and deform the tropo PV (the only one that really interest us at the end of the day) to make it send cold air to southern latitudes like europe. It can be disturbed by the tropospheric weather patterns at 500hpa. OR there can be a disturbance in the strato PV (SSWs are the strongest ones) that CAN propagate down and in reaction disturb also the lower PV (this is where it gets complicated cause not always a stratospheric event will disturb the lower PV, sometimes it just wont reach or even have the opposite effect and strengthen it). But thats why we also look at the higher PV.
What Mark showed here is that last year despite having so many SSWs and stratospheric events, for various reasons the tropo PV stayed strong and the winter was warm (AO+ most of the time). This year the weather is very dynamic in this early autumn because both parts of the PV are weak (AO- AND zonal winds in the strato are also weaker than average, 24:40) and even though it looks like the strato PV will get stronger past mid october (36:42), the lower PV will maybe stay weak on the long term (37:06, going into early winter maybe?). So whats important to undersand is that we look at the stratospheric PV to try to see what it could do on the tropospheric PV in some cases, but its always this last one that will decide what the weather does.
Thank you. Also i would note that the atmosphere at the poles is much thinner than at the tropics which has an influence on the stratospheric/ tropospheric interaction..
I was windering whether/ when the Honga Tonga eruption would make an appearance in thus video. It explains the unusual stratospheric influence on lower levels and the weather patterns from El Nino to the recent transition to El Nino..
Apologies for the typos. No edit function after posting..
And the last words should of course be:"la Nina"..🤭
I keep on mentioning the Tonga eruption. It released an extra 10% of the total water vapour that is currently on earth.
That is a lot if extra moisture and a lot of extra energy and heat.
Very informative updates.
Great update as always Mark
Great vid Mark. Really appreciate the time you took to explain your thinking
Such an interesting explanation of what the MJO is and how it operates to influence other aspects of the climate on a global scale! You have explained the processes without sounding patronising but still managing to make it accessible for someone without any geographical qualifications, just a keen interest in the weather. This type of attention to the how and why is the reason why I enjoy this channel so much. Very nicely done Mark 😀
Thank's Mark very interesting update with the Madden Julian Oscillation as it circulates through the different phases I found it fascinating.
Very well explained..bit late watching but made it. Many thanks
Very good explanation so a big thank you from me. I have learnt a lot from just a couple of your videos.
Any thoughts on doing a possible long range winter forecast?
These oscillation patterns can run over years/ decades and do change the overall impact. Nice to see Mark putting NOA into context here w the polar vortex, jetstream etc.
There's a huge Ridge over North America that sticks out like a sore thumb in it looks to be sticking around through pretty much all of October in the first half of november.
Mark this is absolutely brilliant! I love the content! Thanks so much
Very good video mark,very informative. Thank you.
Great Video, Mark! I love the longer videos
Thanks for an informative video.
I like the in depth look into the weather😊
Will it snow this winter?
Mild, wet and windy of course.