BlueHedgehog074

You know things are interesting for the cold weather enthusiasts on the models when the number of members viewing the thread reaches 3 digits!

Will probably find, as is the case sometimes with these things, some kind of half way solution between what the ECMWF/GEM shows and what the GFS shows. Nice to see the GFS showing a bit more of a cleaner evolution to Greenland heights though.

For a bit of a fun comparison, this is what the GFS was showing for later on Wednesday today from Monday 21st November, And this is what this morning’s GFS is showing at the same time for later today: Still showing 2 separate cores of the Vortex, although the one nearer Greenland on today’s GFS is a little further North-West and looks a bit spidery with what seem like legs extending out from it. The Azores High was more amplified and vertically stretched through the UK on the first chart, though both still have the blocking extending North-East from the UK. Could perhaps argue that the upper heights on the first chart are overall just a little stronger, especially over Western Scandinavia, on the first chart. Overall, however, when looking at the general pattern the GFS hasn’t done too badly at all modelling today’s pattern from over a week back.

Blocking continue to look solid to the North-West of the UK at 192 hours on the 12 ECMWF, with the -5*C 850 hPa temperature line (bar Western parts of Ireland) flooding South to cover almost the whole of the island: No danger at the moment of the pattern becoming too Western based on this run, but will see how the next 2 frames go.

Unless you use one of these

While there is no guarantee snow will seize the UK from this blocky pattern (except maybe Northern High ground), the outlook the charts show are not like the below. Far from it: Strong Vortex to our North on our side of the Northern Hemisphere combined with Atlantic, Westerly drivern weather. Worst nightmare for cold weather enthusiasts. Where as, while details will still change at that range, the outlook for beginning of this December below is completely different… …and is like the of the charts for the cold and snow fans. (Just got to pray now that any signs of deeper cold and wintrier weather in the far out range of the models gets down nearer the 0 hour mark, even if it means having to wait. But this is still a big step up compared to what is typically endured during a number of Decembers).

The Low heights surrounding the Greenland High with those Vortexy pieces dropping South through Scandinavia seem to cage it in, and the squashy Low Pressure systems on the High’s Southern/South-Eastern flank stop it from sinking like a boat. No escape for you, High! And no greetings from the Western based -NAO!

Yep, best not to take anything in deeper FI too seriously. The wild swings that occur and the hugely varied emotions it can bring. Kinda glad though have left the teddy and pram at home. Didn’t feel the models were too bad this morning in all honesty. Especially the GFS. That Low does seem to be less of a trouble maker this morning. Certainly on a few of the operationals I’ve seen. One thing about the 00Z ECMWF at 240 hours (which I appreciate as mentioned earlier by some others not taking output beyond a certain time frame too literally), is a little tweak East/South-East with that UK Low Pressure and the South-Western Greenland High would make it more of a dream scenario for the cold weather enthusiasts.

Ar, I’m so angry with the models this morning. I mean why couldn’t the developing North-Easterly for next week on the GFS be very very very very slightly stronger. The 850 hPa temperatures are 0.01% too warm and the blocking to the North of the UK could do being 0.0001% stronger. And seriously, that 10 day ECMWF ensemble mean is a joke. Why couldn’t that mean Low to the South of the UK just be 1 mile further East? Is making me feel so negative

A reasonable effort… …from our most beloved model in the galaxy - the NAVGEM! Examples from its 12Z run at both 144 and 180 hours above. Variation of the general Easterly theme. Despite the flow being a touch South of East at the surface for the UK, it does try getting the colder 850 hPa temperatures over Northern and Eastern UK sinking further South. Nice looking cold pool over Scandinavia that could spill our way with more favourable orientation of the Northern UK/Scandinavian High (though I appreciate the run only goes to 180 hours and there has been a prospect for the High Pressure - some of it anyway - to get pushed over to Iceland/Greenland. Good for directing colder upper air our way). While not worth getting very engrossed in the details at this sort of range, a little shift East of that Western Spain Low would be very welcome. And like some runs from other models, having the Low be less ball-y.

Good point. It just seems unrealistic for each and every run to be spot on. Sometimes, a model could throw out the most perfect outlook ever, but there’s always chances it gets watered down on the next run or so. So not a bad thing if the models aren’t always churning out appetising triple chocolate cake-esque runs. When you think about it, Northern blocking and bitterly cold Easterly or North-Easterly winds isn’t something that’s common at all during UK Winters. I think reminding ourselves of this can hopefully help to keep down some of our expectations. When blocking to the North of the UK does happen, it then, depending on a persons weather preferences, feels more magical. Especially also if it leads to snow and very cold conditions.

That is certainly possible. Can’t be ruled out.

I can, in a way, understand some of the worry and frustration considering all the let downs the cold weather enthusiasts have had to put up with before. While some will be after chillier and less disturbed weather which next week is likely to provide, probably more so across Northern UK areas, for those after something more (including deeper cold and the white stuff ), I think we just don’t want to feel as though the pattern will be just for nothing. However, there’s no definite guarantee of what will happen in the future. This includes any signs from charts and ensemble systems that seem to be promoting some kind of West Based negative NAO (North Atlantic Oscillation pattern). It may happen. But it may not… especially as any West Based -NAO patterns are currently stored away in the dungeons of FI. Now if it was something that gathered pace, gets increasing support and gets to within 100 hours or so, then it’s worth considering letting loose the dollies from the prams. I have known times in the past where Western Based -NAO patterns become more Eastern based to favour UK for cold weather. In fact, even some instances where it gets too Eastern based and cold takes a holiday over the nearby continent. As I think a few pointed out earlier, some of the outlooks concerning the break down of the Scandinavian High and the naughty South-Western UK Low is just one of the ideas of how things could progress from the upcoming blocked weather pattern. Variation of a theme really. Unless anyone has one of these, it’s just too early to know for sure. It is very possible that as the Easterly/South-Easterly flow strengthens next week (unless things change still), that some cloudier periods along with some showers could blow in from the East, some of which may be wintry over high ground. Especially in heavier showers. Those towards Western UK, particularly West of high ground, seeing the best of the brighter spells. Wintriness and intensity of showers depending though on how the models continue to handle the Easterly flow and the strength and extensiveness of the cold pools to the East/North-East of the UK. Many of the models do show the 500mb heights next week to be quite high over the UK, even when the Easterly flow tries to establish from mid next week onwards. So probably nothing particularly unstable, but a possibility of these highest UK 500mb heights lowering further into the outlook we progress. Then leading to more pronounced showers and longer spells of precipitation. More so, from any disturbances in the flow. But again too far out to be too preoccupied about at the moment. It’s clear many of us have a great passion with the weather and I do think it’s okay to get upset and let out a bit a steam at times. It’s just the nature I suppose for a number to feel up and down from the day to day variance the models show. Though we have to remind ourselves really that weather is something not to take too seriously. Well at least not all the time as I get, for example, the frustration of being locked into a weather pattern you absolutely despise! Not getting too drawn in by the charts constantly, either. Where the strong emotions and disappointments can then come about. Always worth taking a break, too, if the models and stuff gets a bit too much for you. More likely to come back feeling refreshed. One other thing will just add (apologies in advance if it has been posted), the NOAA 8 to 14 day 500mb anomaly chart continues to look inspiring for Northern blocking opportunities with a chance the core of the strongest heights getting drawn near to Greenland. Very slack and variable upper flow over the UK. No Atlantic on-slaught or the risk of negative Western Based -NAO pattern developing on that chart (for the cold weather enthusiasts, may it stay that way). Can be encouraging when these anomaly charts show these sort of outlooks. Brings some extra confidence for opportunities for cold weather. What I will perhaps say is a little shift further East of the lower than average heights around Spain would be ideal, though it could be a lot worse. https://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php Thankfully, and as some others also had addressed in the thread, this is near the start of Winter. Even if this first attempt of Northern blocking for the upcoming season not deliver the snowy treats a number of us want (without totally ruling out next week may provide a small chance of the white stuff, especially high ground up North), then later into December, otherwise January, February or even March could unlock the white goods. (Edit: PS- there’s admittedly been times myself where I’ve experienced the getting-too-hung-up-on-the-charts business, so I realise I’m not really immune to it) From what they were showing yesterday, even though this morning’s ones will be based on the latest data, can always hope that they just caught the wrong train…

Can this sort of outlook make it down to 0 hours. In one piece?

For a spot of fun, the 00Z JMA throws up this scenario this morning at 264 hours: The Northern UK High Pressure gets squashed up towards Iceland and parts of Greenland creating quite a nice block in that area. Few runs from some models that are playing about with retrogression at the moment. The 850 hPa temperatures might not be that impressive at the time on the JMA towards the end, but I imagine those colder 850 hPa temperatures would flood down South through the UK. Shown a demonstration earlier on in the run how an area of the Vortex up North breaks off from the one over the Central Northern America/Canada area. This then swings down South-East squeezing the UK/Northern UK High out West to form a block over Western Iceland. A keen Scandinavian trough develops as a result, also. Black arrows shows this process, while the red arrows shows what happens to the blocking High. Vortex ends up splitting into two lobes: This again just for amusement. But a good thing to see to prolong cool or cold weather. And to help unleash the Arctic! Too far out to get too mouth drooly over, but hopefully something that can develop from this blocking pattern. Also, a welcome back to Nick!

Some rocking times ahead! In the closer range (I guess someone has to do it ), and it looks like some further disturbed weather to come before the likelyhood of UK/Northern-Eastern UK blocking ganging up on the Atlantic Lows. Using the 00Z GFS as an example, today looks like a bright and fairly dry day for most places as a transient ridge of High Pressure to the South of the UK provides some less unsettled conditions. Could still be breezy in the Westerly flow and some showers are likely over Western areas of the UK. More frequent over Western Scotland. Fairly mild in the South (temperatures in low double digits towards the far(ish) South), but cooler further North. Tomorrow sees that ridge transfer towards the East of the UK with a deep Atlantic Low out West bringing a disturbance Eastwards through the UK with outbreaks of rain spreading Eastwards. South-Eastern areas holding onto the driest, brightest conditions ahead of the rain out West. Quite mild again in the South and a little cooler further North. But a bit milder overall than today (although could feel cooler for the areas under the rain). Windy at times, especially over North-Western areas. Rain reaching most areas (while having cleared Ireland) heading early into Sunday. The rain making its escape Eastwards through Sunday (probably clearing Eastern areas early to mid afternoon). A brighter day for most to follow, but still with a keen South-Westerly flow over the UK. Some showers likely over Western and Northern areas. Southern/South-Eastern areas holding on to the mildest temperatures, but quite cool or chilly everywhere else. The Low Pressure that was over the Iceland area on Sunday will head North-East through Monday across the North of Scotland weakening as it does so, and becoming pinched and squashed against the Scandinavian block over North-Eastern UK. There is also a ridge of High Pressure from the Azores trying to build in from the South-West. Flow becomes North-Westerly over the UK. And, apart from a few showers over Western and North-Western parts, it should be a mostly dry and bright day. Eastern and South-Eastern areas probably escaping without any showers (except perhaps the odd isolated one). Chilly in the North, and quite cool further South. A little cooler overall compared to last few days, but still could be pleasant where the sun peeps through. Plus, temperatures probably for a time in low double digits in the far South. While the details could still change a bit, the Azores ridge should start extending some of its upper and surface heights North/North-East through the UK on Tuesday bringing a still and dry for many. Quite cold across Northern areas (temperatures in fairly low(ish) single figures) and fairly chilly across the South. Although has been covered by many others, by 144 hours (Thursday morning from the 00Z runs), some of the Azores/UK ridging will have merged with the Scandinavian blocking bringing the possibility of a chilly flow from the East, (more so for Eastern and South-Eastern UK parts). GFS 00Z ECMWF 00Z UKMO 00Z Both the ECMWF and UKMO look to be the cleanest regarding the evolutions leading to the light Easterly over Eastern parts of the UK. I suspect details will continue to change at that range and while there is good support for a strengthening North-Eastern UK block through next week, am going to leave the sledge locked away for now. (The GFS 06Z for example ending up showing a different variation on a similar theme for Thursday morning): Might look quite iffy and reminds us of the fact that things just may not go as how most of us wants with regards to cold and the white stuff. But the most important thing really is the final platform the weather pattern train ends up getting to. (PS: don’t actually have a sledge… yet )

Not sure I’ve ever seen an area of black that large on an anomaly chart before. That Northern UK block is literally made of steel!

Not the best at analysing these, but the latest NOAA 8 to 14 day 500mb mean chart also continues to look rather good for chilly weather possibilities. Strong enough height anomalies to the North/North-East of the UK to suggest blocking is likely. And in fact, the chart tonight now showing signs of heights going below average South of the UK over the nearby continent. https://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php Yesterday, it didn’t even show any blue in that area: (although to be fair the difference isn’t that big). Upper flow over the UK you’ll notice is more slacker on tonight’s chart than yesterday’s too. Would say in regards to the 18Z GFS update, that it is just one run and, as many of us know, the GFS can be yo-yo(ish) from run to run. Likely also due to how far it goes out. We felt, however, it was worth opening this store tonight. Sounded like some needed it

Feel it’s worth saying that what it does still show on is latest update, that the NOAA/CPC 8 to 14 day 500mb anomaly chart is showing signs of the Atlantic wanting to go for a snooze out West. A reasonable pressure rise in that area extending from Iceland and Eastwards through Scandinavia. The upper flow across the UK mostly turns to the North-West - rather slack. Should cause the hat and scarfs to start coming out of the wardrobes bringing a few shivers. Climate Prediction Center - 8-14 Day 500mb Outlook WWW.CPC.NCEP.NOAA.GOV

At least with sleet you still get some white stuff mixed in. Sorta a shame about the 850 hPa temperatures that get drawn over the UK not being particularly cold. But then, to be fair, the Easterly/North-Easterly setup is quite far away, plus there is more than the 850 hPa temperatures which determines whether snow will fall to low levels. Synoptically, the 12Z GFS is certainly impressive. The Polar Vortex being held captive on the other side of the Northern Hemisphere

Looks like it. Maybe it’ll still show a cold run anyway

If Wales wins the match, the next GFS run will be cold with plenty of snow…

Indeed Phil, and can help bust up the Vortex, particularly when you have 2 ridges of highly amplified High Pressure areas (2 wave pattern?) trying to slice the blue and purple monster up. A great thing to see. Is the case with the Azores High, it can act as both a friend and a foe for cold weather setups for the UK. Would probably say for the 12Z run, it’s been becoming kinda more of a friend, even if it was being a bit naughty nearer the start. In a way, the faster the Azores High is able to ridge North (trying to beat the Atlantic Lows from running over the top), the more likely and quicker the Jetstream out West diverts some of its Low Pressure to our South and strengthen any North-Western European troughing to our South or East. As longs I guess the pattern upstream behaves itself to make that happen. A more established European trough, providing it doesn’t set up too far West, then assisting in propping up Scandinavian/High Latitude blocking. From that (assuming the block was orientated favourably), a chilly visit from the cold and, at times, snowy choo choo from the East or North

A verrrrry big king-sized High, too! I do agree though it is a nice looking Northern Hemisphere profile.

Going for 5.9*C and 70mm of rain and snow. Thanks.