Zakos

Agreed very interesting ... the block is extensive and essentially in the same position right out to +384 hours on the 00z... The block holding firm throughout... tentative signs perhaps of an easterly flow eventually over the U.K... This is quite unusual for November... I haven't seen charts like these since Nov-2010... not to imply we will necessarily see a similar epic cold spell but the potential certainly is there....

An interesting period of cold and unsettled weather ahead, giving an opportunity for significant snowfall in the south, aswell as country wide snow showers. Not a snow-fest by any means but a welcome relief from this rather drab winter we have had so far I'd say. Thereafter, tentative signs of some notable cold encroaching from the east. The 06z is a drastic improvement... with high pressure centred over Scandinavia. This is what we want to see in the output IMO. A potently cold and snowy spell of weather could soon be upon us... The 06z unfortunately fires up the PV over Greenland, scuppering the cold spell just as the cold air gets to our shores... The CFS output for the month however would have us locked into a cold pattern for weeks on end.I personally feel this is the more likely scenario, it has been hinting at this for several days now and the blocking signal grows ever stronger.

Are the models programmed to factor in the effects of a sudden stratospheric warming? I don't believe they are, and this could explain the model volatility at present. The jet stream definitely trending more southerly on the majority of runs as they come out.The low imo does not pose an imminent threat to my untrained eye. looking at the satellite images, a lot of energy going eastwards. I think with luck the cold may hold on for sometime.. SVID_20180227_0827.mp4

excellent, a significant increase in pressure over Scandinavia at 93 hours, forcing the jet stream to take a more southerly track. This is far from over!

Me too. I'm not clued up on the science behind it, but I have heard that this is the case before on this forum. I believe the density of this brutally cold air should make it harder to shift. I believe "thickness" charts indicate air density Even without a block holding cold air in situ, logically it should be more difficult to shift than a less cold air mass. 2 days for a large swath of Europe seems awfully quick. The GFS has already backed down from its rapid breakdown, and it appears the 18z may be following the same trend...

I agree, such deep cold air is unlikely to displaced this quickly imo thats an incredibly hasty warm up from the gfs for western Europe in just over 48 hours... I dont buy it...

what a beautiful chart from the ECM. I believe the cold will already be too deep and entrenched over Europe for the Atlantic to spoil the fun as quickly as some models suggest.

Yes I believe so

Agree. Always far too quick with the Atlantic. I'll eat my hat if that cold pool is virtually removed from Europe within 4 days as the 18z shows

Unbelievable model viewing. I'm lost for words, and teeming with excitement. The block in question is monumental, and any supposed breakdown is very unlikely to be modelled with any real accuracy. Agree with other posters, GFS loosing the plot and "defaulting"to norm, there is no way imo such deep cold would be removed so quickly from Europe. The trend imo had been to increase the strength of the block and the severity of the cold that hits the uk. Are we in for a direct hit ? I unfortunately took a break from model watching, and almost jumped out of my chair when I saw the charts. I think we are in for a memorable event folks

] Good to see the cold pool over North America removed, with the jet becoming drastically weaker. This should help to keep the atlantic at bay. Without a raging stream perhaps the next time around we could have more luck and see an easterly flow develop?

Just to highlight as others have mentioned, the sea temperatures are below average to the North West, which will aid the snowfall potential. I believe the sea temperature has been above average in this area in recent years. Im personally looking forward to this event, even though I am unlikely to see any significant accumulations. It looks like the most potent North West incursion I can remember seeing in recent years

Wow Thats some incredibly cold air heading our way on the 06z, looks like the huge cold pool that has built over siberia may have the UK in its sights! The run ends with what has to be the most beautiful anomaly chart i have ever seen. Definitely a strong signal now from the models for heights to build out the NE, and to have low heights to our East/South East. with a bit of luck we could be in for a memorable cold spell IMO.

. I'm not certain, but given the potency of this cold shot, and the warm seas at this time of year, the temperature contrast could create disturbances in the airflow,leading to heavier and more widespread snow showers. And these possibly wouldn't be picked up by the models until nearer the event. Some GFS runs I believe have shown widespread snow showers across the UK, however the 18z appears to have a "wishbone effect " to flow, with many inland areas staying dry. Does anyone know what factors can cause a northerly to produce widespread snow showers inland?

Strong indication from the GFS and ECM in the long range for europe to be locked in a significant cold spell. The jet stream at present is astonishingly weak for the time of year, I see little evidence in the output for a return mild weather conditions once the cold air becomes entrenched I think a lot of coldies on here were left bitterly dissapointed from the last 2 seasons. But Im now personally convinced that we are in for noteable spell of cold weather, possibly a prolonged one if heights rise to our North East as some posters have hinted at. It's already been fantastic model watching so far this season, which seems to be getting more exciting and promising for cold prospects as times goes on.