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frederiksen90

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  1. 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
  2. Really strong blocking signal at Greenland and Iceland at 300+ hours in GFS ensemble http://modeles7.meteociel.fr/modeles/gens/runs/2019121712/gensnh-21-5-300.png http://modeles7.meteociel.fr/modeles/gens/runs/2019121712/gensnh-21-5-360.png And at the same time, the east wind is now hitting 30 hPa: https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_UGRD_ANOM_ALL_EQ_2019.png Maybe this can help amplify the blockages at solar minimum, which can expand the cold potential? Maybe the trends between Christmas and New Year can really be the sta
  3. Recent studies have shown that more than half of SSWs occur when MJO enters phases 6-7. Interesting if the trends of a weakened PV towards the end coincide with the evolution of MJO in phases 6 and 7? https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foregfs.shtml
  4. Compare to 2009: https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_HGT_ANOM_ALL_NH_2009.gif Here, PV is markedly strengthened in October with downward movement. At the same time, increasing tropospheric blocking prevents a coupling, which then significantly reduces PV. Today we seem to have seen the peak of PV in October? Now, is increasing tropospheric blocking by forcing PV into a displacement / weakening in November? https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_HGT_ANOM_ALL_NH_2019.png After all, does it seem c
  5. Yes, Matt Hugo mentions the same thing as Judah Cohen yesterday about whether the combination of aluetically low and scandi-high in mid-November can disrupt PV and possibly lead to an SSW subsequently, as it lies on each side of the Arctic. This is exactly what led to an early SSW in 2009/10. It is good that PV is stronger than normal, which can collect very cold in the upper stratosphere. If it is quickly attacked afterwards, an SSW allows to push very cold air away from the Arctic. Interesting things are already appearing in the PV forecasts despite the strengthening. In 2009, PV also streng
  6. Bemærk, at den stigende opadgående blokering i troposfæren fortsætter nu: https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_HGT_ANOM_ALL_NH_2019.png Selvom vi forventer en styrket PV , forbliver denne tendens ud over dag 10, hvor vi konstant ser toppen af den zonale vindstyrke. Samtidig opretholder vi en negativ NAO og stigende blokering i troposfæren i de første 5-7 dage. Jeg er opmærksom på, at blokeringen nu ser ud til at kunne stige lodret, så vil opadgående bølgeflux fra troposfæren svække stratosfæren og sende en SSW i 30 og 10 hPa? Dette modsæt
  7. Are we heading into -PDO? Now note the sea at Alaska and the west coast of America. It gets colder and colder as the hot water moves west: https://www.ospo.noaa.gov/data/sst/anomaly/2019/anomnight.10.17.2019.gif This is how it looked a month ago: https://www.ospo.noaa.gov/data/sst/anomaly/2019/anomnight.9.16.2019.gif
  8. Because seasonal forecasts do not predict an SSW, this does not mean that a significant SSW cannot occur. Keep in mind that last winter was a unique case, with forecasts predictably an early SSW, which Europe did not see the effect of. Going back to 2018, a historic SSW emerged within 2-3 weeks in February, which subsequently resulted in a much better impact for Europe at the surface. SSWs may come suddenly, as models can never foresee several weeks ahead. For example, 2009 and 2012 are also. I would just like to point out that the forecasts did not foresee the stable negative NAO over the yea
  9. A strengthened PV with + AO is well up to winter, as it is understood that the air around the Arctic will be colder than normal. At a weak PV there is higher pressure and the air mass will be warmer over the Arctic. Then it will be difficult to get cold. So that's why it's good that PV is amplified to begin with. The most important thing is that NAO does not follow. The worst thing is, if it changes phase, then it becomes difficult. But keeping it neutral to negative while AO goes in + can a subsequent weakening of PV give us even colder air in Europe than if PV had not been strengthened? And
  10. Is the solar minimum driving the interaction between NAO and SST? Recent studies have shown that SST anomalies change with some delay between solar maximum and solar minimum. At the same time, the NAO suggests following the sun's AP index (geomagnetic activity). Looking back over the last 10 years, we have a clear tendency for changes in SST to follow changes in NAO. The most positive NAO values were around the solar maximum. Since then, NAO has been downhill slightly with a cold-warm-cold Atlantic tripole that has maintained colder waters around Greenland and warmer waters at Newfoundlan
  11. Perfect SST anomalies in the North Atlantic. The sea is designed to be warm all the way around Greenland and Iceland, while the cold water at Newfoundland has developed and grown. https://www1.ncdc.noaa.gov/pub/data/oisst/navy-anom-bb.gif We now have a very good tripole, which contributes to a weakened pressure gradient and very favorable for an -NAO and blockages from the beginning of winter. It gives hope for an interesting winter coinciding with low geomagnetic activity on the sun.
  12. Det er måske godt, at prognoserne er milde. Sidste år var stort set alle kolde og blokerede. Men jeg må indrømme ærligt, at jeg synes, at forholdene er meget bedre i år. Vi har ramt solminimumet med meget lav geomagnetisk aktivitet, NAO har været stabil negativ, troposfæren helt blokeret gennem året, og QBO ser ud til at vende mod den østlige fase. Endelig har vi en tripole i det nordlige Atlanterhav, der favoriserer en negativ NAO (også modsat de sidste 5-6 vintre) med varme omkring Grønland, især Vestgrønland såvel som koldere vand ved Newfoundland, der igen udvikler sig: https://www1.n
  13. Studies show that low geomagnetic activity coincides with negative NAO and a warmer arctic via increasing blockage and interconnection between the troposphere and the stratosphere. It is striking that after the solar wind has been unusually weak in 2019, the blocking frequency on the Atlantic side of Greenland increased, leading to the reverse ocean circulation of recent years, while tropospheric blocking has continued for months coinciding with negative NAO. Exciting times, because then we may very well have an interesting winter ahead in Europe. https://link.springer.com/article/10.1007
  14. https://www.esrl.noaa.gov/psd/data/correlation/qbo.data
  15. Actually, it's not the number of sun spots that matter most. It is the AP index - the sun's geomagnetic activity that has shown exquisite correlation with the NAO since 1970. The phase of the lowest activity of the solar wind typically occurs after the sunspots are reduced and at the beginning of a new cycle - and it is therefore possible that one cannot see any major correlation between "just" solar minimum and regional / global climate. Usually, the stratosphere and troposphere are not coupled in the summer - but experts have wondered that recent stratospheric warming has affected tropospher
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