Paul123

There appears to be a pretty close relationship between max wave1 in November and NAO in December https://publish.twitter.com/?query=https%3A%2F%2Ftwitter.com%2Fantmasiello%2Fstatus%2F1197347865481404417&widget=Tweet Maximum wave 1 this November off the chart: Seeing some real continuation of the wave1 pattern in the upper layers of the stratosphere as new Eddy heat flux is generated over Russia. Also because of the favorable conditions of the troposphere for blocking because of the solar minimum, we may expect a siginificant blocking signal next month over the Atlantic. I am wondering if the displacement of the SPV will be enough for an official SSW, later next month.

The warming of 22-24 November will lead to a Canadian Warming and a wave 1 of exceptional magnitude for the time of the year. As a consequence the SPV will be displaced to the Russian side of the North Pole. That's where it begins to be really interesting. By the end of the month and the Russian High (troposphere) will intensify again (mainly because of the long lasting AO+). For the beginning of December a huge heat flux is being calculated, due to the all known wave breaking. I would like to know something more about this wave breaking. Is this wave breaking taking place in de troposphere, over East Siberia (picture 2)? Secondly: is it purely a coincidence that the heat flux in the stratosphere shows itself at the transition of the Canadian wave1 and the Russian wave2. What kind of mechanism is taking place? The early December heat flux leads to a wave2 at the upper levels of the statosphere over East Siberia (Picture 3). West of this second wave is an area of intense heat flux, but at the east side of the Candadian wave also strong heat flux is taking place. Is this second one a downward heat flux?

Possibly a DSW. Hence, the new classification classifies SSWs when the ZMZW reversed at a thickness of at least 80 hPa between 10 and 100 hPa for a band between 60 and 70N for at least two days in a 5-day period. Since the new classification method aims at classifying SSWs based on their thickness, it is subsequently referred to as the Deep Stratospheric Warming (DSW) classification. http://bibliotheek.knmi.nl/knmipubIR/IR2018-05.pdf With significantly stronger impact on troposphere (picture shows the 300 hPa anomaly) than an ordinary SSW. Anyway, plenty of downwelling in the long run.

After the heat flux that will cause a Canadian Warming (picture 1) the focus is on the next warming event, which is very likely to take place in the third decade of this month. This new round up is looking to be bigger than the previous one and likely to reduce zonal winds (10 hPa 60N) once again (after a temporary increasement). Everything still is going on track, hopefully enough to deliver that SSW we are all longing for.

The vortex is under attack, indeed. A next heat flux (not visible on the Eddy heat flux plot so far) starting December 12th will likely cause a further displacement towards Siberia and the zonal winds may drop a lot more. It looks like we are heading towards a Canadian Warming, in the second half of December.

Amazing, this SSW, how intens the warming is and how prolonged. It gets another boost in about ten days, over Northern Canada, where the cold pole has been centered for months this winter. It is bound to have some effect on the troposphere and it looks as if there are some signs of it, on the progs. I very well understand the feelings of disappointment concerning the effect of this SSW, but it is hard to knock down a very strong tropospheric vortex in a very persistent winter like this. Let's see how it works out this time.

Sorry guys, double post. I don't know how to remove it.

I found the link to de daily data (https://www.esrl.noaa.gov/psd/data/composites/day/). This is the anomaly for the first three weeks of 2018. It looks as if this is not particularly typical of a La Nina pattern, especially because of the Rocky Mountains high. There should be a low over there. The high stretches out over the North Pole into Northern Russia. The high over Nova Zembla may be linked to the snow cover anomaiies in Russia, in accordance with the findings of Judah Cohen. December also showed this anomaly. Anyway, there seem to be other forcings in play than the La Nina, this year.

Thank you everyone for your posts in this interesting thread about teleconnection science and background signals. If I understand it correctly, the current negative AAM is responsible for the enhancement of the effect of the La Nina (please correct me if I am wrong). I have some remarks on this issue. I performed a quick study of the effect of a La Nina on the winter pattern, since 1950. I considered the 20 strongest La Nina’s, according to the ranking of the NOAA (https://www.esrl.noaa.gov/psd/enso/mei/rank.html), for January and February combined. We see that overall the effect in the Atlantic on the 500 hPa is neutral. Only very strong La Nina’s show an enhanced zonality (ranking 1-4). December had a ranking 20, in January the La Nina seems to be fading a bit. I have my doubts weather the current AAM (still) is enough to account for the lacking of blocking in the Atlantic and over Greenland, so far. Furthermore: the type of La Nina also plays a role in the teleconnection. This winter we have a EP La Nina. This should a least have some weakening effect on the zonality, in the Atlantic (https://www.researchgate.net/publication/271737956_Impacts_of_two_types_of_La_Nina_on_the_NAO_during_boreal_winter) Finallly can anyone show me where to find the NOAA link where I can create composites using daily data, instead of monthly? I would like to check the 500 hPa anomalies for the first weeks of January. Perhaps there are daily records of the ENSO, a possible weakening of the La Nina may be verified.

Simply E-QBO and sunspot number <50 To the right: E-QBO and sunspot number <50, without winters with new cycle W-QBO cycle starting in upper stratosphere. :Look much better than we have had recent years: Hoping the E-QBO won't fade away as has been suggested by the ECMWF.

The European warming in the stratosphere next weekend on 30 hPa (picture 1) may be helpful to enable a change in weather patterns over Europe. The ECMWF run today (picture 2) shows a ridge, that possibly for the first time will not be overrun by the so far very dominant westerlies. Without counteraction of the stratosphere this time, this may be the best opportunity until today to extend the Russian blocking into Scandinavia. http://www.netweather.tv/index.cgi?action=stratosphere;sess= http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=1&type=1&archive=0 Also noticible: the synopsis in East-Asia and the Pacific is encouraging wave2 activity, putting pressure on the stratospheric PV.

I see no hope for any relevant disturbance of the polar vortex within two or three weeks (see picture). I think the stratosphere is playing a significant role in spoiling the potential for cold weather in Western Europe these days. It seems the long term potential for wintery weather is partially a relict of the Canadian warming, end November, early December. There are still vast areas of below normal temperatures (Canada, Siberia), they continue to have a blocking effect on the tropospheric PV. http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=10&carte=1

Tropospheric ridging is oncoming the end of this year. Due to...? No MJO, no stratosphere, simply tropospheric? I suspect that the extreme cold over Siberia (and Canada?) has its effect on tropospheric ridging. However Siberic coldness still is a relict of the stratospheric warmth from November and start of December, especially the Canadian warming. If this is true, Canadian warmings (also SSW's) not only have direct (dripping down) effect on the tropospheric polar vortex. This way their effect can be stretched beyond the original limits. March 2013 cold may be another example of this stretching, reaching beyond the 2 month limit after the SSW. I however do not know whether other factors played any role during that time.

Thank you for answering my questions, so a Canadian Warming it is. It is quite a lot of years ago (16) when the last one occurred! It still is possible, despite the AGW.

On what conditions do we speak of a Canadian Warming, I wonder? Is there a wind reversal required, at 60 N, 10 hPa? If not, will we meet the conditions in the near future, looking at the morning EC progs? http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/northpole/index.html CW data don't always match a SSW.