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Model output discussion - after the beast, what next?


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1 hour ago, blizzard81 said:

Some people on here have been shot down in flames for daring to state what has been the glaring obvious trend of today's runs. Please feel free to hurl insults or sarcastic comments towards me when I state a cold, hard fact about the trend of the day - The centre of the scandi high is now modelled to be MUCH further south west this coming Saturday than what the models were showing yesterday and the day before. This in turn greatly reduces the risk of any meaningful, widespread snowfall this weekend. Not what many on here want to hear but we all know that we simply do not always get what we wish for in this life. 

A complete exaggeration on Sunday when it first really picked it was even more south than current UKMO which of that matter went more north compared to 00z. 

DD90DC97-21AC-4564-8F63-9B423931A9EB.thumb.png.4942ac1fe0e4fbf21a0f381f9fd7524d.png

Ignore these models then? Of which are still carrying baton for widespread snow away from Scotland. There has been no huge shift that’s incorrect to suggest so. Expected variance. 

Just as much chance as a north adjustment..

DF791D0A-1FC8-47DA-B4E3-8F4C885AE85A.thumb.png.ee9483795c033e84d72c2bd396d773ea.png4CE5767A-9E6C-43F8-B589-1D586A554509.thumb.png.d4fa4c8406d870e1bcc8d13f00594e1b.png05FB0D23-3CE7-4227-B215-726DC0CCAAF7.thumb.gif.8e04714760e2af0b56afe780558c76a7.gif33DA53C5-D124-4215-B7AD-7E841B453B7D.thumb.png.dbe49b4e34aed80858ae9a4ead9af20a.png

Edited by Daniel*
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The UKMO 144 has teased me out if hibernation - for a comment. 144 shows a very meridional flow across 50N with deep cold filtering into Scandi- could be a sharp transition from mild to cold

No mate, I'm still in winter mode as long as the Gfs shows potential arctic blasts..hope it continues!❄❄❄❄❄

Ahhh another chocolate teapot in your post... I believe the last one froze. It seems that we are seeing the second response to the SSW with another surge of negative zonal mean u winds heading fo

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all gone south,people bickering about it yesterday well done you Got your wish, bitterly cold,not just chilly lol,with uppers approaching minus 16c but mainly dry ,what a waste ,boring ZZZZ

Edited by SLEETY
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Yes it looks like  the current weak surface Artic high drops some heights over Scandinavia and that sinks towards the Azores wave. A weak feature with little WAA to sustain but it does alter the flow of colder uppers to give us a very cold draw for a few days. Not sure the prospect of snow is that great even in the SE/South, though flurries are possible. More a UK cold high for most than an easterly and certainly no block per se, the NH is driven currently by the PV meandering with little strat to Trop forcing, and minimal wave activity from the mid lats. 

As usual the models over egg these setups, exaggerated HP now being more realistically modelled. Not really seeing any potential for high latitude blocking even with the PV weak, just no action to kill it off. All very frustrating bearing in mind the strong SSW. It does make you think that even with exceptional background signals a memorable Winter is still very elusive for our little island.

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Still looking at very cold charts this morning, with uppers widely between minus 12 and minus 15 for a time. 

That's pretty much the same as February 28 - boy that was cold!

It currently looks less snowy on the output than it did 24 hours ago, but I don't think we can be sure on the snow bit until T48-T72, when we can see models like HIRLAM. A lot of the other models were a bit clueless on the last easterly where fronts were not involved. I would have thought anywhere south of the Humber needs to be kept on watch.

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The envelope remains extraordinarily wide on the 00z suites thanks to gfs whose model suite  (op and ens mean) takes the cold pool through e France, close to strasbourg!  Meanwhile, ec and icon flying the flag with the former the furthest north across s England. Gem, ukmo in the middle ground over the Low Countries. With ec and gfs at both ends of that envelope, experience tells us that ukmo looks a good call. (And that would be a pretty good showing from the model (if I verifies like that)

eps shouldn’t vary too much from the mean at day 4 but they showed a considerable spread on the last run (six clusters) so still to be pinned down I expect from the model. it’s only Wednesday - expecting to know what Saturday will bring apart from cold remains elusive. 

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12 minutes ago, bluearmy said:

The envelope remains extraordinarily wide on the 00z suites thanks to gfs whose model suite  (op and ens mean) takes the cold pool through e France, close to strasbourg!  Meanwhile, ec and icon flying the flag with the former the furthest north across s England. Gem, ukmo in the middle ground over the Low Countries. With ec and gfs at both ends of that envelope, experience tells us that ukmo looks a good call. (And that would be a pretty good showing from the model (if I verifies like that)

eps shouldn’t vary too much from the mean at day 4 but they showed a considerable spread on the last run (six clusters) so still to be pinned down I expect from the model. it’s only Wednesday - expecting to know what Saturday will bring apart from cold remains elusive. 

I must admit that the UKMO has been pretty much rock solid sending the upper cold pool just south of the UK. Will be fascinating where it ends up. 

My thoughts are still unchanged this morning. Parts of the SE (Kent in particular) could have 10-15cms and other parts from the Humber south a covering. The Channel Islands could also do well this time as they were a little too far south with the last beast. 

Time will tell but considering the Scandi high hasn't even formed yet I think we will have to wait intil the 12z tomorrow to firm up 

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No change to the 00z models, a bitterly cold weekend, especially further south with a strong Easterly flow across southern uk bringing some snow..temps struggling to get much above freezing and feeling sub-zero due to severe wind-chill..becoming progressively more settled and sunnier further north due to high pressure but cold everywhere with sharp overnight frosts..winter is returning!:cold::)

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Eps broadly in line with the op

mean SLP 1015 mb London day 4

ukmo and gfs are 1020 + 

heights a little more difficult to pin down which is going to be important re the uppper cold pool which brings instability 

eps still cut across s england -  with the spread keeping areas a bit further north in the game on this. 

More runs required !!

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image.thumb.png.bd77316685aa9a8bb5fd76d818aed98d.png

Quite the change on the ensembles this morning, quite a few more runs keep any decent cold to or over the south of the UK. A small few keep things cold (obviously less so then the weekend!), These are a bit slower bringing the easterly in but managed to build heights north to keep us on the cold side of a high.

Real risk this may go south this morning and a small but growing cluster have the cold pool actually missing the UK altogether,

What seemed like a clear picture yesterday is one that looks far more unclear this morning.

Edited by Quicksilver1989
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4 minutes ago, Quicksilver1989 said:

image.thumb.png.bd77316685aa9a8bb5fd76d818aed98d.png

Quite the change on the ensembles this morning, quite a few more runs keep any decent cold to the south of the UK. A small few keep things cold (obviously less so then the weekend!), These are a bit slower bringing the easterly in but managed to build heights north to keep us on the cold side of a high.

Real risk this may go south this morning and a small but growing cluster have the cold pool actually missing the UK altogether,

What seemed like a clear picture yesterday is one that looks far more unclear this morning.

This does seem quite bizarre that the closer in the more uncertainty.

You normally have to side with op runs at day 4 because of the higher resolution.

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19 minutes ago, Quicksilver1989 said:

image.thumb.png.bd77316685aa9a8bb5fd76d818aed98d.png

Quite the change on the ensembles this morning, quite a few more runs keep any decent cold to or over the south of the UK. A small few keep things cold (obviously less so then the weekend!), These are a bit slower bringing the easterly in but managed to build heights north to keep us on the cold side of a high.

Real risk this may go south this morning and a small but growing cluster have the cold pool actually missing the UK altogether,

What seemed like a clear picture yesterday is one that looks far more unclear this morning.

ECM individual ensembles are equally uncertain, but with an envelope slightly further north. What this means is, by just Saturday, the cold pool could land anywhere between Glasgow and Paris. SE England favoured but no reason for certainty on any outcome!

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16 minutes ago, nick sussex said:

This does seem quite bizarre that the closer in the more uncertainty.

You normally have to side with op runs at day 4 because of the higher resolution.

Indeed given the nature of the swings you get the feeling some unwelcome changes may still be afoot.

The synoptic pattern does bear some resemblance to December 2012... in that there may not be enough of a westerly push. However I still expect areas to turn very cold this weekend given that is what the operationals are showing at the moment and any disturbances forming in the flow are going to have a big impact. Not quite at that range yet.

Edited by Quicksilver1989
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Nice update from UKMO extended at t168 showing milder air starting to move in from the west

ukm2.2018032100_168_lant.troplant_prp_fcst.gentracker.thumb.png.262687fd6dad00107e18e9e78f8d3234.png

 

ECM taking a similar route only difference is a bit more rain for Scotland

ecm2.2018032100_168_lant.troplant_prp_fcst.gentracker.thumb.png.9db74a9cd594dd128ff292deb277a7bb.png

:)

Edited by Summer Sun
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Yep ^^ Mild on the horizon

lets get this weekend out the way first with one last hurrah !

IKON 06z a nice jog North to include a greater portion of the UK

811CCE07-AE14-4F6A-AA2E-A9B5E7088FB0.thumb.png.c0e678f9edca0b75c7b9167e948cff3d.png

Edited by Steve Murr
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The 6z Icon is a correction North, although its starting to look more and more isolated, this is why sometimes I'm not keen on using the spreads, presenting the whole 'envelope' if you like as a range of possible solutions, people still saying that suggests Scotland is a possible entry point when in reality it isn't, the spread may reach there but that may be 2 members or 3 out of all the ensemble suites going wheras I can guarantee its a lot more in Southern UK, still say the ECM eps mean will be on the money - rock solid as usual, maybe a tiny tiny bit further south than there.

Edited by feb1991blizzard
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Morning all :)

It all got a little heated (unlike the weekend's forecast weather) in here yesterday evening.

Let's be honest - the weather doesn't care what you want, I don't care what anyone else wants either. There's an "Ignore" option if you want to use it and in any case we are utterly powerless and helpless against the vagaries of the atmosphere - nothing personal, it just doesn't care about you or me.

So, all we can do is deal (so to speak) with the cards we are dealt and in that spirit the cards for the morning of Saturday March 24th have hit the table so time to pick up and have a look.

Starting as always with ECM 00Z at T+240:

ECM1-240.GIF?14-12

A vigorous and deepening LP is moving SE toward western Scotland with frontal systems crossing the British isles bringing wind and rain. Colder air behind the cold front is likely to bring a traditional spring mix of sunshine and heavy showers with snow on hills. The question is whether the LP will continue and ESE trajectory into Europe and pull in some colder Arctic air.

GEM 00Z at the same time:

gem-0-240.png?00

The evolution is very different to the ECM. The former takes the HP SW through the British Isles and absorbs it into the Azores HP quite quickly. With GEM the HP remains over the UK a little longer so the Azores HP builds more into Europe allowing the trough to dig further south west of the British Isles. This promotes a mild SW'ly airflow over most of the British Isles and dry for many ahead of the approaching frontal systems which are making only slow progress east. 

GFS 00Z at T+240:

gfs-0-240.png

Something different again emphasising huge uncertainty after this weekend. The HP from Scandinavia sits over the British Isles and intensifies giving us a week or so of largely fine weather with improving day temperatures as the colder air recedes but still with night frosts. Eventually, the HP splits with one part going to the Azores and the other heading SE into Europe allowing a weak Atlantic system to approach but this heads SE and the British Isles is left in a slack S'ly flow with showers or rain confined to south western areas. Further into FI the Azores HP becomes more dominant but it transfers into the North Sea as a new MLB leaving the British Isles largely fine under an increasingly cold E'ly by Good Friday.

GFS 00Z Control at T+240:

gens-0-1-240.png

This morning's GFS Control at mid-range looks like the ECM OP with a negatively tilted trough close to northern Scotland and a fresh NW'ly flow over the British Isles. Further into FI and the LP disrupts south down the North Sea putting the British Isles into a N'ly airflow and the trough expands with a new LP crossing Ulster heading ESE as Good Friday dawns.

The 00Z GEFS at T+240:

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

Considerable uncertainty into the medium term with a lot of options on the table. Given a call, I'd say the majority have LP or a trough close to or over the British Isles. 4 or 5 have winds from a SW'ly or WSW'ly direction but plenty of others have Northerlies and Easterlies and the greatest spread is over the British Isles so plenty of confusion, As Easter approaches, there's a trend to build heights either in the mid Atlantic or from the Azores but far from resolved at this stage as you'd expect.

In conclusion, a messy and unsatisfactory picture this morning. Any lingering hopes of a prolonged cold spell via retrogression have been extinguished but how the HP passes through the British Isles after the weekend is far from clear. ECM has a rapid transit through to the Azores allowing the Atlantic to play a hand again while GEM has the HP hanging on a little longer promoting a gentler evolution while GFS gives us several days of calm weather as the HP intensifies over us. Given that huge diversity, it's very hard to make a call at this time but the Atlantic remains largely weak and disorganised and the hints of jet movement observed yesterday have also faded so nothing zonal and nothing settled. The tendency for LP to head SE on a negative alignment into Europe (which has really been the story of the European winter for me) continues and while that does it's unlikely to be warm for any length of time.

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Funnily enough the Gfs 00z gives the south / southeast another easterly with minus 10 uppers at the end of the run!:D:cold-emoji:

Edited by Frosty.
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23 minutes ago, feb1991blizzard said:

The 6z Icon is a correction North, although its starting to look more and more isolated, this is why sometimes I'm not keen on using the spreads, presenting the whole 'envelope' if you like as a range of possible solutions, people still saying that suggests Scotland is a possible entry point when in reality it isn't, the spread may reach there but that may be 2 members or 3 out of all the ensemble suites going wheras I can guarantee its a lot more in Southern UK, still say the ECM eps mean will be on the money - rock solid as usual, maybe a tiny tiny bit further south than there.

To me, the eps spreads don’t take the cold pool n of the midlands. The odd outlier may go to the border but outliers should be excluded. Eps say the envelope is Birmingham to Brussels. That puts Kent in the middle. Clearly other models are elsewhere. 

 

 

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5 hours ago, The Eagle said:

00z GFS - non eventful (the odd snow shower for 12 hours), chilly, spring on the way.

 

 

Maybe for you Eddie but there a few odd people that don't live in Dublin - methinks?

image.thumb.png.97f4a3112eca371bc0b6daaeee19e89e.pngimage.thumb.png.f35fa67087c90ad8b35c343556900ec7.png

Models are notoriously bad at being able to pick up convective snowfall which is highly probable with the exceptionally low upper air pool forecast to traverse a large sector of the UK. The SE in particular (where MOST people live) should be most prone.

:)

Edited by Purga
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57 minutes ago, Summer Sun said:

Nice update from UKMO extended at t168 showing milder air starting to move in from the west

ukm2.2018032100_168_lant.troplant_prp_fcst.gentracker.thumb.png.262687fd6dad00107e18e9e78f8d3234.png

 

ECM taking a similar route only difference is a bit more rain for Scotland

ecm2.2018032100_168_lant.troplant_prp_fcst.gentracker.thumb.png.9db74a9cd594dd128ff292deb277a7bb.png

:)

Hmmmm Low level cloud and drizzle but at least it will be mild...... Darlington must get some protection from the Pennines otherwise they are pretty poor spring time charts IMHO.

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