TEITS

My view on the models is this. Whilst we all know the rollercoaster ride of following potential cold spells in the output. However it is the thrill of the chase that can be just as exciting as the actual weather it brings. I'm sure storm chasers will say the same thing despite often being a bust. In recent years the most disappointing aspect of our winters is the lack of cold spells to even chase. That certainly cannot be said for the position we are currently in. The GEFS mean SLP for Iceland, Scandi has certainly changed with both showing an increase to 1020mb. Based on the output if the blocking does occur then it is much more likely that our cold spell initially originates from blocking over Greenland/Iceland with a corresponding N/NE,ly flow. Original post: https://community.netweather.tv/topic/99584-model-output-discussion-into-winter/?do=findComment&comment=4983998

I haven't seen Tamara post for a while. I might be still have my reservations on teleconnections but I always like to read Tamara's thoughts. She is someone I have huge admiration for and her posts are always a delight to read. I only wish I could be as articulate. Getting back on topic. My only concern about the output is the timing of this change in the models occurring over Xmas. I always say im dubious of the output during Xmas Day, Boxing day and it would be hypocritical of me to not mention this just because of the cold output it is showing.

My view on the models is this. Whilst we all know the rollercoaster ride of following potential cold spells in the output. However it is the thrill of the chase that can be just as exciting as the actual weather it brings. I'm sure storm chasers will say the same thing despite often being a bust. In recent years the most disappointing aspect of our winters is the lack of cold spells to even chase. That certainly cannot be said for the position we are currently in. The GEFS mean SLP for Iceland, Scandi has certainly changed with both showing an increase to 1020mb. Based on the output if the blocking does occur then it is much more likely that our cold spell initially originates from blocking over Greenland/Iceland with a corresponding N/NE,ly flow.

The GEFS SLP mean for Iceland & Norway are heading in the right direction. So we have plenty to keep us interested as we head towards 2024. However some pleasant surprises may occur between Xmas and the New Year. I shall remain rather dubious of the model outputs over the next 48hrs , as I am every xmas.

The 06Z GFS just goes to show you don't always need mega blocking and super cold upper temps. The disturbance tracking along the coast of S England brings intense enough rainfall for this to drop the air temperature and turn to snow. The output might be disappointing if you're seeking a prolonged, severe cold spell. However between Xmas Day & the New Year I think the position of the jet stream will keep many of us interested in following the models.

I'm not sure I agree with that. The 12Zs continue to show some marked differences and this can also be seen on the GEFS ensembles as early as +120. Whilst any prolonged, severe cold spell is very unlikely for the remainder of Dec. A spell of snow cannot be ruled out should we see the slider low pressure and the following NE,lys as this moves E/SE. Lets also remember that we have members who live in Scotland who continue to have a greater chance of seeing some snow.

Not sure what to make of the output this morning except wonder whether all the models have been infected by a virus. This past week has been a farce and continues to be so when you compare the models at 168. Yesterdays 12Z GEM was also similar to the 0Z UKMO. So what does this all mean? Answer no idea whatsoever and like the models they have no idea what will happen between Xmas and New Year.

The slider option is something I mentioned a few days ago. Just call me Septic Peg.

I haven't seen anyone hype anything. That is because the consistency of the model output has been so poor nobody knows what is going to happen. This past week the models for Xmas period have suggested extreme wind, snowfall, very cold max temps, very mild temps of 15C in E Scotland, NW,lys & SW,lys. The advancement in weather forecasting has obviously been improving due to increased computing power. However at times, especially winter, forecasting has not improved beyond 3-5 days. This is especially true when I think back to the weekly countryfile forecasts in the late 80s.

You are indeed correct. As is often the case the operationals always prove more reliable than ensembles at short range. For example the 0Z GFS OP was much warmer than the GEFS mean on the 27th Dec and yet the 06Z GFS is the same. When this happens and is supported by the GEFS control run then the GEFS mean slowly increases towards the operationals in future runs. As for positive background signals. Funny how during the past 10 years despite all these different positive signals we always end up with the same winter weather pattern i.e SW,lys with pressure relatively high to the S of the UK with very little signs of any blocking at N,ly lattitudes. Maybe these teleconnection signals may of proved correct and gave the UK the promised winter wonderland many years ago. However are these positive signals being overridden due to changes in the global weather patterns due to a warming climate. If so then at the moment nobody fully understands how climate change will affect our weather patterns. You cannot make a successful prediction if you do not understand the cause. Original post: https://community.netweather.tv/topic/99584-model-output-discussion-into-winter/?do=findComment&comment=4978478

You are indeed correct. As is often the case the operationals always prove more reliable than ensembles at short range. For example the 0Z GFS OP was much warmer than the GEFS mean on the 27th Dec and yet the 06Z GFS is the same. When this happens and is supported by the GEFS control run then the GEFS mean slowly increases towards the operationals in future runs. As for positive background signals. Funny how during the past 10 years despite all these different positive signals we always end up with the same winter weather pattern i.e SW,lys with pressure relatively high to the S of the UK with very little signs of any blocking at N,ly lattitudes. Maybe these teleconnection signals may of proved correct and gave the UK the promised winter wonderland many years ago. However are these positive signals being overridden due to changes in the global weather patterns due to a warming climate. If so then at the moment nobody fully understands how climate change will affect our weather patterns. You cannot make a successful prediction if you do not understand the cause.

Not convinced any output is correct at the moment. I do not wish to give false hope but note the chart below. Note the low pressure over Newfoundland which develops on the 06Z and is a very different chart to the 0Z. Many times rather than moving E as modelled the main low stalls with part of this being ejected SE. What then happens is you get a weak surface high pressure around Iceland. I'm not saying major blocking is on the way. However a cold, wintry xmas cannot be ruled out and might not be as shortlived as currently modelled. Original post: https://community.netweather.tv/topic/99584-model-output-discussion-into-winter/?do=findComment&comment=4976932

Not convinced any output is correct at the moment. I do not wish to give false hope but note the chart below. Note the low pressure over Newfoundland which develops on the 06Z and is a very different chart to the 0Z. Many times rather than moving E as modelled the main low stalls with part of this being ejected SE. What then happens is you get a weak surface high pressure around Iceland. I'm not saying major blocking is on the way. However a cold, wintry xmas cannot be ruled out and might not be as shortlived as currently modelled.

This is the main reason why I don't post as frequently in the model discussion thread. Nowadays I just get up view the morning model outputs & ensemble means and that's it. Whereas years ago I would view every model run and study every single ensemble member.

Nice to see an improving trend since I last posted. If the output continues then its the type of weather pattern when in locations such as mine you would struggle to acknowledge the cold spell whilst experiencing max temps of 6C and sunshine. However exposed locations to the NW,ly who are at higher elevations could be facing white out conditions and heavy snowfalls. You can guarantee some idiots will need rescuing in the scottish mountains who ignore the likely warnings. A few more things to keep an eye on. Wind could be a major feature as some ensembles have much deeper low pressure than the operationals. Any snowfall may not be restricted to high ground as depending on the timing and intensity could bring snowfall to lower levels. Possible low pressure running across the S of the UK around Xmas. Could either bring a snow event or a rain turning to snow as the low clears E.

Disappointing model runs but this isn't surprising to me. Some of the previous GFS runs showing a N,ly around xmas were really only glancing blows. The SLP ensembles clearly show no sign of any high latitude blocking with the Iceland dropping below 1000mb on Xmas eve. The SLP mean for Oslo, Helsinki hover near 1002mb as a W,ly flow blasts into Scandi. By the end of next week/weekend the pressure could be at 1040mb for my location. Only glimmer of hope is this high may move W into the following week and may allow some brief colder N/NW,lys. Unlikely to be severe or sustained as the polar flow is likely to be cut off due to a lack of blocking over Greenland.

Looking at the model output and reading through some of the posts means I shall repeat what I say every winter. For those who are new to the forum or following the computer models just remember some of the promising teleconnection signals you read about on here mean absolutely nothing if this isn't being shown in the actual model output. If I had a pound for every time the MJO is looking favourable or any other signal then I would be spending my winters in Lapland, Spring in Oklahoma, Summer in Florida. This isn't knocking any individual on here using such methods because at least you are trying to make a forecast. Unlike some organisations who make silly forecasts saying "Chance it could turn colder with snow after xmas but more likely to remain mild, unsettled". That isn't a forecast but just stating the obvious and covering all bases. So for newcomers following the models, it can be less stressful and more reliable by just sticking with the GFS,UKMO,ECM to +240 and looking at the ensemble means. Another tip for newcomers if I ever predict an E,ly in the future just ignore me!

Overall a disappointing set of model runs. A rather unsettled spell of weather until at last mid Dec looks on the cards. Beyond and a hint we may see much colder weather via N,ly towards Xmas. However as per usual the GFS does tend to produce incredible cold synoptics at +384. Sorry for being a misery but my normal methods of looking for signs of a cold spell are at the moment disappointing. The Iceland SLP mean does not suggest any blocking in that area with the mean dropping to 995mb. Even the likes of Helsinki & Oslo have a 850hpa mean of only -5C. This suggests the mobile W,ly pattern will affect even these areas.

My initial thoughts for this winter is a much greater chance of a colder winter compared to recent years. Although not on the scale as 2010. This is based on no science whatsoever. More of a instinctive prediction based on years of following weather patterns .

Words cannot describe what im currently experiencing. Suffice to say this is the sort of rainfall/wind I would expect if I was living in Texas!

Chucking in down with thunder here just to the SE of Peterborough.

Bloody awful. I got soaked yesterday when coming home from the hospital. Currently its chucking it down and windy and its only 17C. However I don't envy my family who live in Palermo, Sicily! Only positive from this weather is my plants are having a good soak.

Disappointing lack of storm activity here. We need the rain and despite all recent warnings I have only seen some heavy downpours last sunday.

Blimey this morning is a pleasant surprise. I knew some snow might be possible but all models yesterday were suggesting this would become light and patchy as the low travels east. The intensity of the precip is much heavier hence the heavier snowfall. Currently huge flakes with a covering everywhere. Just a shame this band of snow will clear here in about 1hr!

Still holding at 0C and still seeing snow falling in the heavier bursts. Looks as though just to the S of Peterborough some intense convection is kicking off. Despite enjoying this snowfall you still cannot beat a good old E,ly with bitter temps, dewpoints and dry powdery snow.