Joe Levy

This chart from the 18z is nice for coldies. It brings low thicknesses and fairly low uppers to our shores, with wintry potential lying therein. Nothing major, but interesting nonetheless.

I am not looking for cold in the time frame that the ECM currently covers, as I don't believe the upstream pattern would yet be right by that stage. I am more interested in the development of the NH profile through the latter stages of the ECM, such as the development of high pressure over the Arctic. It will take time, but I do still believe the second half of January has a lot of potential, based on strat forecasts and the wise words and analysis of numerous members of this forum who continue to educate me with their technical knowledge. We need to wait for that time frame to come into range before we can start seeing stellar runs in my opinion.

When we first spotted the Asian warming in the output however long ago that was, I wasn't actually expecting to see any major impact on the NH profile until around mid January at the earliest. Perhaps my expectations were wrong, but as far as I am concerned, since the GFS is only now starting to cover mid January, the effects of this warming on the output have not reached their most significant. I wouldn't be able to comment scientifically speaking, but the arctic high at the end of the GFS 6z certainly looks resilient.

Thank you, I do try to be reasonable in my posts! I enjoy the weather full stop so model watching for me is fun whatever it shows, even if it is continuous. Also, one half of my degree is anthropology, so if I am not analysing the models, I am assessing the personalities that fluctuate and interact on this forum! Fascinating stuff, you will all become part of my dissertation next year I am sure

Yes because we trust every single ens output... Okay maybe this particular run has no cold outliers. However, that does not define the actual outcome, it merely hints at possibilities. 20 runs will not cover every possibility. Remain open minded and resist getting drawn in by any single run or even a series of runs, as changes can be rapid or they can be gradual, whether that be mild, cold, dry or wet.

Good clustering on the cool/cold side and the op was some way above the mean at day 10, so pretty good for cold prospects as far as things stand at the moment.

I find it interesting how many different interpretations people can gauge from this one chart. For some it is a cause for optimism, for others pessimism. Personally, the only word I am inclined to use is 'potential'.

January is still a week away which is not exactly short range, and the rest of the Winter and March, well that's obsurdly far away! There is already stratospheric warming scheduled to take place in January - it doesn't have to be sudden to benefit us! The Met Office are as prone to error as any major forecasting organisation so do not write off a period of 3 months on the basis of a long range forecast. The Met Office provides a clear disclaimer explaining about the experimental nature of long range forecasts.

To my eyes, the 18z GFS is better at 144 hours, but someone correct me if they think otherwise! Ridging between Scandinavia and the Arctic and a better tilt on the Atlantic low.

Merry Christmas everyone! It just wouldn't be Christmas without model watching on Netweather!

It tends to take a couple of weeks before warmings in the strat filter down to the troposphere, so I am not sure if those Arctic heights are a product of that warming. If they aren't, then who knows, maybe the warming will strengthen existing heights!

I definitely agree about the importance of trends and to that I would add that as far as I am aware, strat forecasts are often more reliable than surface forecasts (someone correct me if I am wrong) so that strat chart is not as 'FI' as we would normally assume with charts at that distance.

Consistently showing up on the GFS, and continuing to either maintain its predicted strength or even increase, the forecast of an Asian stratospheric warming is fast becoming a potentially significant feature for our weather in January.

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=309&y=138 The GFS 18z ENS for London - whilst there is nothing remarkable about this set in terms of 850hpa temps, there is certainly some scope for fairly widespread wintry weather based on a few of the ensembles. However, that is not very likely at this stage and is looking in the shorter term. On the other hand, for longer term prospects, if you get a chance to look in more detail at the synoptic charts for the ensembles, the variety of options on offer is certainly broad. When we consider this and other interesting pieces of data we have noted this evening, I feel like the next few weeks will be very exciting for model watching for all sorts of reasons!

On that particular chart, the isobars are tightest some way to the South West of Cornwall, perhaps the Isles of Scilly would record some very strong gusts. On the Northern flank the isobars are fairly close together over the Central Lowlands of Scotland. However, the very worst gusts are not over land in that specific chart.

The GFS 18z shows how the chopping and changing of the models can make a huge difference to what sort of weather we will get, but one thing it certainly keeps consistent, if not improves, is the stratospheric warming over Asia, and also enhances the one over Newfoundland and the Northeastern United States. This is something we definitely need to watch. If this keeps showing up on future runs, then Mid-January could be interesting. In the meantime, plenty to keep us busy with the conflict over the next few weeks and dramatic spells of wet and windy, sometimes wintry weather! Stay safe if you're in a risk zone and enjoy model watching!

Very interesting indeed! Thank you! At those distances in time, there is quite a bit of variation, so it will be really fascinating to see how the models perform in the coming weeks, especially when we now have a bit of conflict between them

What about post 144 hours? Just curious to see how the models perform beyond the fairly short term

At the end of the GFS 12z, the stratospheric warming over Asia is much more pronounced than I have seen on previous runs. If it verified, it would be the most significant warming of the season so far at that latitude

What sort of features should we look out for in future output for this particular time period? Is it only strong winds that we should be concerned with, or are there other potentially disruptive elements as well?

I quite enjoyed that run of the GFS. A fairly weak and divided PV, a southerly tracking jet and low pressure over Southern Europe. As far as trends go, that's one I am pretty happy with. Also, that Asian stratospheric warming shows up again and is still slowly moving closer in time rather than being kept at bay. One to watch for later on in January methinks

Just for fun, but the 18z gives us this little feature on Christmas Day that pulls in cold air quickly behind it and with intense precipitation, has wintry potential. Not to be taken too seriously at this range though

Extreme weather isn't good for anyone. I am hoping for an average winter with a little bit of everything but not too much so that noone gets hurt! Back to the model discussion anyway... like many other people I am hoping that the ECM isn't correct and that the UKMO is closer to the mark, but with such a changeable pattern that is prone to creating lows from that extreme temperature gradient off the Eastern Seaboard, who knows what will happen!

I read a statistic which had been validated and checked, but I cannot find the source now, that stated that we are more likely to see a white Easter than a white Christmas! So the model output at the moment is far from surprising, we have just been spoilt by recent years where significant cold weather prospects have emerged earlier on in the year than we had grown to expect.

The NH profile is interesting on the 12z. On the 6z, low pressure had successfully breached northward through the area of high pressure spanning the Bering Straits by this stage. On the 12z this hasn't happened yet. I don't know what the implications are, if any, so input would be welcome! EDIT - the jet is also very amplified over the Western side of the United States at 240hrs