The hunt for cold - Model discussion (late November)

[Derecho]

06z swingometers

In the shorter term it looks as though a good consensus is beginning to emerge of some milder air starting to come in as a result of the low to the rest but temperatures will be pretty close to average not cold enough for snow. You can see what is expected of this week from the anomaly charts:

 Across UK and Europe temperatures only slightly below average now, a marked contrast to 5 days ago but rather seasonal at least.

 By the end of the week UK temperatures look set to be near average. From this anomaly chart you can see where the cold air is being concentrated.

And global temperatures 0.51C above the 1981-2010 climatological average.

All is not lost though for coldies, although recent runs have been a let down some Greenland highs are beginning to emerge. As the low clears from the UK some of these runs see the cold air following behind. It's a shame we can't get a snow event out of that low next weekend. A bit of patience though and it may get better thereafter

 This highlights the mild swing in the long term but where there are cold runs there is hope...

Edited November 19, 2018 by Quicksilver1989

[Catacol]

5 hours ago, Steve Murr said:

Scandi block - retrograde to Iceland - then slides back to Scandi & rebuilds in situ is probably about the best call !

Agree. Exact shape/alignment impossible to call, but northern blocking to continue as we move into December. The current MJO forecast is strong out to week 2 - and this is key. successful verification and the chances of a cold spell in mid December (ish) start to look quite good I think.

[Man With Beard]

3 hours ago, mb018538 said:

Hope so. A week ago people were foaming at the mouth about this little cold pool heading our way at the beginning of this week saying that the model forecast maxes of 6-8c were completely wrong and we would see some snowfall in places. Models were spot on. Dusting over high ground, nothing more than grey and chilly at lower levels.

May I slightly disagree!! The ARPEGE is indicating many areas maxing at 4C or 5C tomorrow/Wednesday - and in fact the ECM has large parts of the south east not even reaching 4C tomorrow.

I think "snowfall in places" is also a fair picture painted of the next two days: The ARPEGE suggests a covering over the West Midlands and higher areas more widely, and the ECM is 50/50 on some snowfall to the NE of London for a time too.

 

 

[weirpig]

 Perbs  all over the place  around a 50/50 split  

[Man With Beard]

And looking further ahead ... the parallel has sadly demonstrated in the past 72 hours that the magic weather forecasting wand has yet to be created

(though I've been impressed at how it has moved towards new solutions in a gradual, orderly manner, rather than the scattergun of the ECM's D7-D10, or the sudden shifts of the GFS op's D5-D8 - far more helpful and useful, keep it up please!!!)

But all the same, the parallel has shown it belongs with the "big boys". 

I think this D8 chart from its 06Z run sums up the upcoming forecast problems nicely!

Slow moving Atlantic low incoming from the west.

A cold front trying to encroach from the east.

Heights in the middle being squeezed.

But how will it look after the squeezing? 

Looks very, very complicated. Two very different ECM clusters this morning at D8, fairly equal in size. (- say it quietly! - cluster 2 looks reminiscent of the more wintry clusters from three days ago with lower Euro heights.)

Unlikely to be resolved soon!

[Team Jo]

Oooooookay.

Nobody is right or wrong here. This is the hunt for cold thread. if you are looking for a more 'balanced' discussion there is the other model thread which might be more receptive to commentary around milder outcomes.

We have the same every year, the weather will do what it wants, chart interpretation is just that - interpretation. If we can keep the personal jibes out of it and remove the emotion from the discussion, it makes this thread a lot easier for everyone to read.

I do think that the 'Winter is over and I'm off to get my deckchair' posts are a bit over the top. Yes we aren't receiving the cold that was hinted at last week, but having just walked back from the station in the freezing rain, it's not the kind of weather I'd be using to top up my tan. So yes, while I accept it's not 6ft drifts out there at the moment, it is certainly more seasonal.

Lots to be resolved, and as ever, don't get hung up on one run.....

[Summer Sun]

GFS P has a deep low west of Ireland early next week and it hangs around for around a week before eventually shifting east giving a cooler spell after which it settles down with high pressure edging up from Europe

 

Edited November 19, 2018 by Summer Sun

[SLEETY]

34 minutes ago, Man With Beard said:

May I slightly disagree!! The ARPEGE is indicating many areas maxing at 4C or 5C tomorrow/Wednesday - and in fact the ECM has large parts of the south east not even reaching 4C tomorrow.

I think "snowfall in places" is also a fair picture painted of the next two days: The ARPEGE suggests a covering over the West Midlands and higher areas more widely, and the ECM is 50/50 on some snowfall to the NE of London for a time too.

 

 

Yet METO have maxes of 9c in SE tomorrow how can their be such a huge difference between various model etc less than 24 hours away,not acceptable really!

[andymusic]

37 minutes ago, Man With Beard said:

May I slightly disagree!! The ARPEGE is indicating many areas maxing at 4C or 5C tomorrow/Wednesday - and in fact the ECM has large parts of the south east not even reaching 4C tomorrow.

I think "snowfall in places" is also a fair picture painted of the next two days: The ARPEGE suggests a covering over the West Midlands and higher areas more widely, and the ECM is 50/50 on some snowfall to the NE of London for a time too.

 

 

mountain forecasts for our area Brecon beacons etc suggest 400m and above - so hill snow only will be favourable

[Man With Beard]

1 minute ago, andymusic said:

mountain forecasts for our area Brecon beacons etc suggest 400m and above - so hill snow only will be favourable

Yes I think fair to say many lowland places will miss out this time, too.

[Methuselah]

Having spent the last six years effectively 'hunting for narwhals in the Persian Gulf', the likelihood of deep cold hitting our shores is, arguably, better this year than it has been for a long while? I look forward to actually having something to hunt, for a change...

[SLEETY]

Yes best to make the most of it,deep cold is so rare in the U.K.Better off going on holiday to Maritime Canada in January ,like Newfoundland for a month to experience an Arctic wilderness ,rather than hoping to ever see it here

[Met4Cast]

The trend within the EPS is to bring up less cold air from the South in the 7-10 day range, keeping this largely in situ with Northern areas staying under the colder air out until day 15

The extended output is largely dependent on what happens days 5-7 Cluster 1 (54%) is with the Det run, high moves too far NW and we see low pressure influence from the S/SW. Cluster 2 (45%) keeps high pressure around Greenland/Iceland, low pressure goes S = colder

Until days 5-7 is resolved, the extended can't be taken seriously, it'd be pure luck if it calls it correct at this point. All models highly volatile beyond day 7, high uncertainty/low confidence in any outcome. 

CR/OP in the same cluster would give credence to lean towards that for the time being, GEFS mean similar to EC Cluster 1, so more support for the less cold solution at this time.

But again - Models do struggle when it comes to resolving energy going underneath high pressure so major flips can't be discounted. Less cold late this week/weekend air into the South at least seems odds on

Small clustering of colder solutions thereafter to end the month/go into Dec but with a wide spread, little confidence either way.

[Chesil View]

Having lived through nigh on 60 winters and followed about 45 of them closely in terms of the info available at the time.

The feeling I get as we head into winter is that the background signals are excellent for our chances of quite a special winter. 

It is worth rembering GP's post from last week that would suggest that essentially we are just watching the furniture being arranged for the main event in the current modelling and rather as Catocol and GP suggested the real fun and games strat wise probably won't, come to fruition until mid December.

Always worth remembering too that none of our great winters in the last 100 years have consisted of winter Armageddon setting in on December the 1st and lasting for three months. Even December 62 had its milder bits and 47 didn't really start untill 22d Jan. In fact the one winter that did start with a snowy shutdown on December 1st namely 2010/11 was over by the day after boxing day.

In my humble opinion What we are going through in the  modelling at the moment are the atmospheric undulations on the way to a decent winter.

Edited November 19, 2018 by Broadmayne blizzard

[Northwest NI]

17 minutes ago, Broadmayne blizzard said:

Having lived through night on 60 winters and followed about 45 of them closely in terms of the info available at the time.

The feeling I get as we head into winter is that the background signals are excellent for our chances of quite a special winter. 

It is worth rembering GP's post from last week that would suggest that essentially we are just watching the furniture being arranged for the main event in the current modelling and rather as Catocol and GP suggested the real fun and games strat wise probably won't, come to fruition until mid December.

Always worth remembering too that none of our great winters in the last 100 years have consisted of winter Armageddon setting in on December the 1st and lasting for three months. Even December 62 had its milder bits and 47 didn't really start untill 22d Jan. In fact the one winter that did start with a snowy shutdown on December 1st namely 2010/11 was over by the day after boxing day.

In my humble opinion What we are going through in the  modelling at the moment are the atmospheric undulations on the way to a decent winter.

I'd settle for that 

[MattStoke]

Can’t see any sign of prolonged mild, Atlantic dominated weather. Just maybe some brief milder/less cold spells. As per the Met Office updates. 

No real deep cold showing up in the model output in the foreseeable future either but the picture of a lot of northern blocking remains in the model output and that will always bring the risk of significant cold developing at some point. Just need the pieces to fall into place. The fact the models don’t show deep cold at the moment doesn’t mean there is no chance of it. Look at the bigger picture instead.

Various background signals also point to plenty of opportunities for significant cold in the winter ahead, from the snippets I’ve seen from very knowledgeable amateurs and pros.

 

[SLEETY]

As long as Northern blocking stays around you always have chance of tapping in to much colder air as we head into proper winter period soon.

Fingers crossed it remains and we don’t head back into usual zonal scenario,which can last for weeks and weeks.

 

 

[Froze were the Days]

Sorry to change the subject but has anybody heard from Frosty and Ian Pannell? (always look forward to his LRF's)

[ItNeverSnowsInWindsor]

We need lower heights over Iberia over the coming runs as this can easily scupper chances further down the line.

[stodge]

Afternoon all

Just a couple of general observations/thoughts from me at this time:

1) The seeming inevitability of the west-based negative NAO which killed the 2010-11 winter stone dead just after Boxing Day always makes me think that those wanting a Greenland HP should be careful what they wish for.

2) We are also seeing the rise of pressure through Iberia as the Atlantic LP throws energy to the east. The only hope is if that ridging merges with the sinking Scandinavian HP (as shown on the 00Z Parallel) and re-enforces a Baltic/mid latitude HP. Otherwise, the ridging goes into central Europe and there we are. UKMO and GEM try to dissipate the energy east but neither ECM nor GFS seem that interested so it's an outsider for me at this time.

3) Looking to the outskirts of FI, the OP, Parallel and Control of the 06Z are all trying to rebuild the PV in its "normal" place and the PV dissipates out of Siberia. Now, this doesn't happen because of a cross-polar transfer as we often see from a Wave 1 attack on the PV from the Eurasian side but it just happens.

4) Many winters have a colder spell late November followed by a much milder interlude in early December (I think 15-18c is entirely possible in early December under Foehn type conditions in places N Wales and the Moray Firth) before a second colder spell in mid December and that's been hinted at by MetO in recent times.

An evolution to a short-lived Atlantic spell followed by a renewed build of HP across the British Isles from the south or south west doesn't look unlikely. Mid December HP doesn't mean snow but can mean inversion with fog, frost and ice days.

 

[Methuselah]

So here we are - the scene is set:

The round ones are in the vice: the tension-music gets louder, and the picture alternates; first onto the victim, then onto the seven-foot-tall Ukrainian people-smuggler (replete with facial scar, tattoos and piercings) who's hand is on the crank...Will it be a squeeze or will it be a release...?

Well it is the 12Z, after all. And time is running out!

[carinthian]

7 hours ago, carinthian said:

Morning all, snow arrived on time, just as predicted by the high spatial resolution snow model from 48 hour out. Amazing accuracy produced, even predicted the start time and snow depth to the hour and cm with my location 1km x 1km. As usual its result was spot on,  10pm start time Sunday evening and snow depth of 5 cm 6am Monday morning. Some of its data is fed from the longer range single powerful model our experts use over here. This model has been rock solid in showing a strong Arctic ridge towards the last week of this month with low pressure over Southern Scandinavia to produce a more meridional flow. Yesterday our team indicated the low would be near Denmark at day 10 and with any Atlantic milder air incursion only making limited progress to remove the cold block developing to the NE ( if any ) So that was a optimistic update for colder forecast. Will get an update from them in about 2 hours time to see how things are looking and will ask for specifics with regards to UK interests. Meanwhile we now have the excellent service of the snow fine mesh model now providing us with hourly information here in resort. Try and get some pictures of the snow this morning to wet your appetite .

C

Picture taken earlier on route from village to the Gontal Valley. Current temp -7c in village and -10c on the Berg.The trough that produced the snow has moved away but the fine mesh model now showing a new pulse of snowfall by tomorrow morning about 5cm in addition to 5 cm earlier. A accumulated total of 11cm forecast by Wednesday morning. Update from the experts indicate little change from the previous forecast model for the next 10 days ( see above post). Longer term range 10-15days shows a build of pressure again over Scandinavia and lower pressure heights transferring from there in to Europe. So an increase in the chance of the UK flow to turn NEly during early Dec. So they seem to back a colder blocking situation to increase, especially as their model still has weaker than normal 300mb  jet wind , plus a split jet which should allow high pressure to dictate a more southerly track in any low pressure systems. Regarding the UK , any milder encroachment  looks likely to be repelled going by their single model but could produce some very interesting seasonal weather for SW Britain. 30% confidence level which really equated is moderate forecast confidence. Hope this helps. 

[BlueHedgehog074]

16 hours ago, syed2878 said:

Just wached The ecmwf seasonal update on gavs weathervids and that isn’t too encouraging for something cold ither it’s not really showing the blocking signals it was showing in the last 2 updates. 

 

Yeah, fairly disappointing when looking at that ECMWF seasonal forecast. Temperatures close to average overall, which is still okay. Would appear the second part of Winter would generally lead to blocking conditions more favourable for cold and wintry weather with High Pressure becoming more and more concentrated further to our North-West or West. More of a back-loaded Winter it seems, but would mean having to wait (though cold and wintry spells earlier on in the Winter are always still possible). Do particularly like the look of both February and March. Not April, however.

Having said that, with a few tweaks January and December could become more favourable for colder and blocked conditions. Besides, there are certainly suggestions that blocking conditions could lead to some cold or freezing weather in early/mid December, if it materialises. But if there is a chance this seasonal ECMWF forecast update becomes close to the mark, then could put up with it (Even though it could be a fair bit better for the cold and snow enthusiasts). Even the High Pressure dominated outlook over the U.K in January that it shows, is much more preferable still, than having constant wind and rain via Atlantic Lows rushing in from the West. 

In fact, doesn’t look like much signs from that seasonal model that the U.K. would be experiencing too much in the way of flat, Westerly, Atlantic drivern weather. And then the fact that the Pressure anomalies for each month are an average, then would imagine there being divergence from this average in cases. Like in December with the seasonal model’s Northern Scandinavian High anomaly, there could be a week where the Scandinavian heights being in control bringing bitter Easterly winds over the UK. Then, one week, the block becomes more of a European High and temperatures being milder. And then another two weeks the High Pressure/high heights becomes more concentrated towards Western Russia with average temperatures over the UK. Something like that anyway. 

Maybe further updates from that model could improve things again for those wanting lots of freezing cold and snow. Getting favourable Northern blocking for cold and snow in the UK for 3 months during Winter is no easy feat, and is rare. But the fact Meteo-France is going for a Winter a little below average, especially for Northern UK, is something I guess. 

No gaurantees these seasonable forecasts will end up being spot on, although that can’t mean any of them can’t be close to the mark.  They’re useful to have to get some kind of guide what the season ahead could be like. 

A great video by Gavin must say. Made for an interesting watch! Thanks for posting this.   

Edited November 19, 2018 by DiagonalRedLine
Changing one or two things

[Spah1]

First out of the blocks is the UKMO at 144hrs. 

[mountain shadow]

1 minute ago, Spah1 said:

First out of the blocks is the UKMO at 144hrs. 

No South Westerly zephyrs there. Would like to see the main trough mid Atlantic transfer Eastwards on the same latitude and pull in the Northerly/North Easterly.