frederiksen90

Big, big run again from EC46 MJO phase 7 is very clear, and possibly next 8. It statistically gives this development : And it happens around the time the strato weakens strongly (mid-February). Then a response to the rise of strong Atlantic/Greenland blocking from below which weakens it all the way up and then the process may then intensify down into the troposphere again in the following weeks. As I see it, it looks like a coupling from below, where the MJO drives strong blocking and the cold propagation with an upward wave of high pressure that moves from the troposphere up into the stratosphere, weakens it above, and then prolongs this process in the troposphere . Then we don't have to wait for an impact after a SSW, as it occurs from below. So it also makes sense that the models have been so consistent about the development. In the case of warming, where high pressure starts in the stratosphere and moves down, you see the effect approx. 10-14 days after, but now you see the potential long before it weakens the stratosphere. This means that the MJO moving into the western Pacific will probably have the greatest influence on the flow change from around 10-15. February onwards. In addition, EC46 is strongly supported by CMC ENS and GFS35 with strong blocking and cold spread from mid-February onwards, and potentially colder over Northern and Western Europe before. It is certainly not certain that we have seen the best winter weather yet.

Wind reversal at 10hpa in EC OP and EC ensemble mean in both 12Z and 00Z 16.-17. january

Doesn't it look more like a split than a shift? https://charts.ecmwf.int/streaming/20231216-2000/6f/webp-worker-commands-64f9dd744-p2f2h-6fe5cac1a363ec1525f54343b6cc9fd8-oflmUL.webp And with strong wave 2 activity now, which is more of a precursor to a split than a dislocation: https://www.stratobserve.com/plots/20231216/tseries/anoms/gfs_nh-hgt-w2-60n_20231216.png

Is there SUDDEN stratospheric warming brewing? Or what happens? It is therefore an extremely interesting change that has occurred in a short time. Therefore perhaps suddenly? EC46 has shown a stable strengthening vortex with a slow weakening at the end for a long time. But now the strong intensifying warming in 10 hPa from the North Pole on its way to Canada/Greenland over the last two days shows. EC 46 on Sunday: https://charts.ecmwf.int/streaming/20231121-2000/47/render-worker-commands-76898cbbf-zdbjw-6fe5cac1a363ec1525f54343b6cc9fd8-rHarLF.png?fbclid=IwAR0cP_ymedoQZbRZKavBj2J2Mf24WvN8uQXUItKx4fHPZBx09ia-na7jVbM EC46 today: https://charts.ecmwf.int/streaming/20231121-2000/8a/render-worker-commands-76898cbbf-z7r8s-6fe5cac1a363ec1525f54343b6cc9fd8-PQSOm2.png?fbclid=IwAR3Fkhjtjlkb2dn2rDGas4NDCrLRBGX6p3xdkIHyVW2pEj8p0pJFWkAQ85w And just look at the change in the zonal wind from Sunday to today: https://charts.ecmwf.int/streaming/20231121-1240/5d/ps2png-worker-commands-76898cbbf-5kktb-6fe5cac1a363ec1525f54343b6cc9fd8-eOe5nM.png?fbclid=IwAR3twESXABbKnetwZf0WI3gVd2qfyF7wXuG_bzpiG_SvMcJaX64rXE1pGBk https://charts.ecmwf.int/streaming/20231121-2000/da/ps2png-worker-commands-76898cbbf-f5rht-6fe5cac1a363ec1525f54343b6cc9fd8-rdu4pd.png?fbclid=IwAR3Fkhjtjlkb2dn2rDGas4NDCrLRBGX6p3xdkIHyVW2pEj8p0pJFWkAQ85w There is something to keep an eye on. It has appeared like a troll from a box with the change from one day to the next, But now suddenly some interesting development happens. And it is perhaps connected with the Atlantic ridge connecting Scandinavia and increasing wave 2 activity? Something is being written here: The tripole in the Atlantic has also developed. The jet stream is much further south than expected. Perhaps as a result of the combination of ice growth and solid cold over Scandinavia, the contrast between cold in the Nordics and warm in Southern Europe has increased. So the flow is further south than normal even in a strong stratosphere. And now with good trends also in the stratosphere. I think it matches very well with 2009/10. I think Europe will get plenty of winter this year.

Is there an early sudden stratospheric warming coming? EC46 continues the strong signal of warming in 10 hPa and it gets stronger and stronger also into December. Note that it is the entire hemisphere that gets warmer than normal, so the heat spreads from the North Pole across Europe. This could indicate much more of a stretched vortex that heralds a split rather than a displacement with resulting heating. And there is a strong signal of Ural blocking into November, which could form a backbone for Northern Scandinavia-Greenland. It is very favorable for wave 2 which are precursor patterns to a split. https://charts.ecmwf.int/products/extended-anomaly-10t/overview/valid_time?base_time=202310260000&projection=opencharts_north_pole&valid_time=202311060000

Warming underway in the stratosphere in late November and early December. It becomes clearer every day in EC46. Really exciting trends. Note that it is the entire hemisphere that gets warmer at 10 hPa. So not just a shift. It looks like 2009 I think. Dynamic November with low pressure in the UK and intensifying Ural block for the next 3-4 weeks: https://charts.ecmwf.int/streaming/20231025-2000/62/render-worker-commands-74964888f5-5qg8g-6fe5cac1a363ec1525f54343b6cc9fd8-cVwWNR.png With eastern QBO and EL Niño. And the same pressure anomalies and trends in the stratosphere already now

Vortex is splitting in GFS 30 hPa: https://max.nwstatic.co.uk/gfsimages/gfs.20221113/00/216/npst30.png

Now it is starting to look like a real Greenland blockade. It seems more like it gets associated with arctic blockade EC12Z-ENS https://wxcharts.com/charts/ecmwf_ens/polar/charts/gph500_anom_20211115_12_240.jpg? https://wxcharts.com/charts/ecmwf_ens/polar/charts/850temp_anom_20211115_12_240.jpg?

Den NAO -indekset i efteråret 2021 til sammenligning med NAO i 2012 2021 https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif 2012 https://1.bp.blogspot.com/-OwO-iO59NXw/UKOoMxTVZKI/AAAAAAAAFHU/YgMrEyqVQ8Q/s1600/NAO_late2012.JPG?fbclid=IwAR3g4aR-Wv9o2UcdqTMrdDPaMufDyU7MYxHqRPa37Gq2XFg9Xh7mawvu7F8 Bemærk den identiske tendens med først en negativ NAO i august begge år, derefter en stigning til kortsigtet positiv i september. Dernæst kraftig negativ NAO i oktober, før en kort stigning igen fra start til midten af november. En generel negativ NAOmed korte afbrydelser. De minder ret meget om tidspunktet for de korte positive perioder i september og november med den mest negative periode i oktober. Går den så i negativ igen i december? 2012 var året, hvor vi var på vej ud af det sidste solminimum (begyndelsen af solcyklus 24) med stigning i solpletter, men med lav geomagnetisk aktivitet. 2021 er med andre ord samme sted som 2012, hvor vi nu igen er bevæget os ind i en ny solcyklus på vej ud af minimumet med en stigning i solpletter, men stadig med lav geomagnetisk aktivitet. Begge år med Eastern QBO og et dødt Atlanterhav. Optimismen er fortsat høj. For det første passer korrelationen mellem AP-indekset og oktober NAO perfekt. Nu stemmer sammenhængen også mellem efterårets NAO- tendens i år med 2012 (begge år samme sted i solcyklussen). Og i forhold til sidste år er den negative NAO blevet endnu stærkere dette efterår. AP/ NAO- forskning antydede, at blokade i troposfæren og en negativ NAO skulle forbedres, når et lavt AP-indeks faldt sammen med østlig QBO . Det kan nu bekræftes, at efter skiftet til østlig QBO kombineret med lav geomagnetisk aktivitet, har vi nu den mest negative NAO- periode siden vi forlod vinteren 2012/13

And when you then see such a 500 hpa anomaly from GFS-ENS for the last third of November, then it really starts to look interesting. Blockage is perfectly located across the Atlantic with troughs over Northern and Central Europe: https://wxcharts.com/charts/gefs/polar/charts/gph500_anom_20211108_12_336.jpg?fbclid=IwAR2-Z7jQvl3LUhOYn9O8JzNZQjE7Vm3maaOb54H7PpI1I1Eupe9FfRsKoVU

It does not resemble the stronger vortex coupling with the troposphere. There is plenty of blockage in the next 6 weeks in EC46. And this may contribute to a further weakening of the vortex and perhaps SSW during December or January. Maybe eastern QBO along with the sun helps to maintain high pressure block and periodic cold into December?

As I interpret it, we see the effect of the Canadian warming in the stratosphere by shifting the vortex to Europe, which provides increasing low-pressure activity over Scandinavia and the opportunity for short-term cool elements from the northwest in the next 2-3 weeks. Then it is clear that the low pressure trend disappears again - all the while the zonal winds of 10 hPa try to normalize. The effect of the Canadian warming disappears at the surface and the signal to go back towards more high pressure over Europe / Scandinavia as well as the Urals in the 3rd and 4th week is quite clear. This may be a precursor to a new and perhaps even more powerful weakening of the vortex. It is also seen that the heat rises in 10 hPa over Siberia in the same period. And once the vortex has weakened sharply once, is there more often a tendency for a warm-up or possibly a split on another attempt? It looks very interesting, because we do not go into a totally dynamic westerly current, but back to strong positive height anomalies, which contribute to planetary wave motion from the troposphere

Men en svækkelse i forhold til mandagens ensemble-kørsel. Ret stor ændring: https://stream.ecmwf.int/data/gorax-green-001/data/scratch/20201112-0600/d7/ps2png-gorax-green-001-6fe5cac1a363ec1525f54343b6cc9fd8-7oWzWZ.png Fra noget, der udviklede sig til en stabil stærk PV, er det nu en større ændring. Måske en tendens mod en stor svækkelse, som bliver endnu tydeligere i næste kørsel på mandag?

What an interesting change u vortex according to EC-ensemble. A weakening on the way: https://stream.ecmwf.int/data/gorax-green-001/data/scratch/20201112-2040/57/ps2png-gorax-green-001-6fe5cac1a363ec1525f54343b6cc9fd8-T8V3Hu.png

Hvis der er et år, der i øjeblikket minder meget om 2020, er det 2012. Havisen er tæt på minimum 2012. Læg mærke til det usædvanligt varme Barentshav og havet jeg det nordlige Atlanterhav vest for Grønland til Newfoundland sammenlignet med september 2012. Det kolde område, der var i Atlanterhavet i tidligere år, er helt væk. Så havet er varmt i hele området. Sidste gang dette skete var i 2012. Samtidig har vi et mindre og koldere område nord for Island. Derudover er PUD gået negativt med koldere farvande ud for USAs vestkyst, omend i mindre grad ultimo 2012 hidtil. Dette sammen med udviklingen af en moderat La Niña i det sene efterår / vinter, hvor vi havde en neutral ENSO i 2012 efter en La Niña. 2012 er sandsynligvis meget lig 2020 ved SSTog havniveau. Spændende om det så fører til højtryksblokeringer denne vinter mere dominerende over Nordeuropa med en svækket solcelle på grund af den lave have ved Barentshavet, hvilken øre sandsynligheden for en SSW / split?