sebastiaan1973

Very small chance for a N/SE/E- wind. Pity.

In De Bilt the chance for a 'E' is very small. But who knows

The anomaly chart

Well. The emphasis on SSW is, due to the changed atmosphere, where cold winter weather seems almost impossible with help of a SSW.

Game over? So it seems.

Dr Simon Lee op Twitter: "22 major Arctic Sudden Stratospheric Warmings in DJF 1979/80 - 2021/22 and the average MSLP anomalies & NAO index afterwards. The point of this figure: there is a *lot* of variability even in just these 22, and it's also been a long time since an SSW was followed by NAO+ Twitter / ? T.CO --------------------------------- I made a selection of the SSWs with the situation of this year [Simon Lee made these charts). 2000 lacks. Average NAO -0,67. 5 out of 6 negative NAO.

James Peacock op Twitter: "The relatively unreliable nature of displacement type SSWs is evident when looking at typical mean temperature anomalies across the period of impact. I suspect there should be a little more of a cold signal over the US though. Split type SSWs, meanwhile, tend to hit hard. ----------------------- So, 'we' definitely need a split SSW.

Excellent anomaly chart third week of January for SSW. Altough there is just a minority with a SSW.

I don't think such a setting (EC-oiper) will bring any signicant cold weather in the UK. Tough, It can be good enough for the Low Countries.

I guess there is little hope for a SSW. MJO is scattered. Not a strong signal.

Seems to me, the latest EC-oper is excellent for wave 1. The trop. polar vortex is located at the other site of the Northpole. Lots of cold air rushed to the sea. Cyclones forming.

Sorry to say. No signal for SSW or significant weakening of the stratospheric vortex. Above 40 m/s is considered strong.

http://Eastern Mass Weather: Winter 2022-2023 Promises Plenty of Mid Season Mayhem

https://www.severe-weather.eu/global-weather/cold-anomaly-stratosphere-polar-vortex-volcanic-cooling-winter-influence-fa/

New tweets by Webb. https://twitter.com/webberweather/status/1586536012238364672

https://twitter.com/webberweather/status/1585677372249935872?cxt=HHwWgMCo1ebKuoEsAAAA And another.

https://twitter.com/webberweather/status/1585830349820481537 An intresting read by Erik Webb. He writes about the teleconnections bringing a negative NAO in 3-4 weeks time.

Latest EC46 for the periode after half november. Stratosphere (not shown) after an increase in the first 10 days of november, the winds are blowing around the normal values.

https://iopscience.iop.org/article/10.1088/1748-9326/ab0385 The upper stratospheric zonal wind anomaly on the initial date plays a role in the winter prediction of the NAO/AO. Around 22% of the 19-year period winter NAO variability can be explained by the initial upper stratospheric zonal wind anomaly in November. An initial westerly anomaly in the stratospheric pole in November propagates downward to the troposphere in December, inducing a poleward shift of the tropospheric mid-latitude jet. Then the anomalous poleward jet shift persists well into January and February, which finally results in the positive phase of NAO/AO. The reverse happens for easterly initial anomalies. The resulting surface response resembles the NAO and AO in SLP and has an amplitude of 1–2 hPa. Latest EC46. Not looking good.

Latest EC46. Some indications for high pressure. First NW-Europe, later on Iceland-British Isles.

An important new study https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022JD037422 The Arctic stratospheric polar vortex is an important driver of winter weather and climate variability and predictability in North America and Eurasia, with a downward influence that on average projects onto the North Atlantic Oscillation (NAO). While tropospheric circulation anomalies accompanying anomalous vortex states display substantial case-by-case variability, understanding the full diversity of the surface signatures requires larger sample sizes than those available from reanalyses. Here, we first show that a large ensemble of seasonal hindcasts realistically reproduces the observed average surface signatures for weak and strong vortex winters and produces sufficient spread for single ensemble members to be considered as alternative realizations. We then use the ensemble to analyze the diversity of surface signatures during weak and strong vortex winters. Over Eurasia, relatively few weak vortex winters are associated with large-scale cold conditions, suggesting that the strength of the observed cold signature could be inflated due to insufficient sampling. For both weak and strong vortex winters, the canonical temperature pattern in Eurasia only clearly arises when North Atlantic sea surface temperatures are in phase with the NAO. Over North America, while the main driver of interannual winter temperature variability is the El Niño–Southern Oscillation (ENSO), the stratosphere can modulate ENSO teleconnections, affecting temperature and circulation anomalies over North America and downstream. These findings confirm that anomalous vortex states are associated with a broad spectrum of surface climate anomalies on the seasonal scale, which may not be fully captured by the small observational sample size. Key Points The broad spectrum of surface signatures of stratospheric polar vortex anomalies is obscured by the small observational sample size A large ensemble indicates the observed magnitude of negative North Atlantic Oscillation and related surface anomalies during weak vortex winters may be inflated Over North America the main driver of winter temperature variability is El Niño–Southern Oscillation (ENSO), but the stratosphere can modulate ENSO teleconnections Plain Language Summary The strength of the winds in the stratosphere over the Arctic provides useful information for seasonal forecasts of wintertime weather over Europe and North America. When we study these linkages, it is a challenge that we have few winters—only about 40—with reliable observations from the stratosphere. Here, we use data from a seasonal forecast model to generate a large collection of 3,000 possible winters, and we use these to examine different patterns of surface temperature and sea level pressure for winters with the strongest and weakest winds in the polar stratosphere. Some real-world episodes have attracted wide attention, including recent cold winters linked to weak stratospheric winds, and there seems to be an anticipation that weak winds in the stratosphere are synonymous with extremely cold weather in many regions. However, our results indicate that these expected surface signatures are in fact not particularly common. There are also scenarios when instead the opposite surface signature emerges. We find that it is not sufficient to know the state of the stratosphere; regional sea surface temperatures can either support or counteract the stratospheric influence on winter weather in any given year.

EC46 shows a La Nina setting for the second half of november and first week of december.

An intresting picture from Simon Lee.

https://twitter.com/giacomomasato/status/1581744230741200897?cxt=HHwWgsDS7er_vfMrAAAA

Simon Lee.