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Model output discussion - cold proper on the way?

Paul

Please keep this thread solely to discussing the model output. The model banter thread is available for more loosely model related chat, ramps and moans.

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27 minutes ago, snowray said:

Not had a chance to post the last couple of days due to bits of business that had to be sorted out, including funnily enough a couple of legal documents that have to be signed in a town in NW Italy at over 400m asl next Thursday. Heavy snow was showing up for this area for Wednesday and Thursday of next week and I was worried that the the solicitor would not be around in his offices if there's 2 or 3 foot of snow or that the elderly signatories would end up stuck in a mountain snow drift, I thought just my luck, hardly any snow south of the Alps and it has to bucket down next week. (Its snowed lots in Central/Southern Italy though of course). 

But out of the blue hardly any snowfall at all is showing this morning for Northern Italy so I thought I'd take a look at the ensembles.

 

London, no outlier there.graphe_ens3.thumb.gif.7c75a8c6a1c5fac42600c3049ba4fe6e.gif

 

 

Lugano (Italian/Swiss border), the operational is a clear outlier.graphe_ens3-1.thumb.gif.ff57607523a03a93ddcd9fe71e4ffa05.gif

 

Florence. North/Central Italy.graphe_ens3-2.thumb.gif.7c18fc56136b801bde01a2266b47586a.gifMassive outlier.

 

So It seems to me that the GFS operational has this Low pressure sinking south way, way too quickly, in view of this I expect everything to be further north again on the 12z runs. I'm not expecting the crazy beast from the east charts for next week, although you never know, but am thinking that UKMO is likely to be on the money, or maybe a UKNO/GFS blend.

UW144-21.thumb.gif.b960b4249cf10e6c4b35c61d1da7c42d.gifgfs-0-144.thumb.png.a279c56d43f5e39d48b1da4ac498cb94.png

ECM has the low even further south, so looking well over done to me, should be some big changes coming up on the 12z runs, certainly less progressive in my opinion.

ECM1-144.thumb.gif.37ecdecf02f69747a6545b9ba4263963.gif

 

Best of the best this morning is the NAVGEM, poor model, but every model can have its day.navgem-0-180.thumb.png.dd22cd7fcdbee171732713a69c39c52d.pngnavgem-1-180.thumb.png.58ebdc5fc9b95ca78708e58905a8254f.png

The up and coming China model also looking great.

cma-0-180.thumb.png.763dae4acbd557035da760256aee5e45.pngcma-1-180.thumb.png.ad0c24532aa2b450efe8ee482a9e1086.png

So hopefully lots to look forward to still for coldies from Tuesday onwards. 

gfs-16-72.thumb.png.4ab78130ccc56828ad679bedb8dcef06.png

 

Anyway, let's wait and see what the 12z runs turn up before jumping to conclusions. I would still prefer that it didn't snow in Northern Italy next week mind, at the end of the day I want it all over here for us to enjoy!😉

You'd be surprised, I lived for a few years (2008-2013) not far from Varese. It snowed every winter, definitely a lot more than in Scotland. 

North Western Italy has a peculiar climate, snow usually comes with southern/south-western air currents. Due to it being surrounded by the Alps, the cold air gets "trapped" and it takes a lot to kick it out. So as a milder and wetter airmass moves over the area from the Mediterranean, it almost always falls as snow. And the snowfall is usually heavy and persistent too.

There are very rarely disruptions even with 10-20cm snowfalls. Roads are immediately cleared and salted and smaller snow ploughs clean all the paths. Major disruptions are very rare, unlike in the UK. 

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I strongly suspect the Gfs 6z operational has got it wrong for later next week..why?..because there are no N / NE'ly winds shown later next week..it's flat calm!

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1 minute ago, Runcible Spoon said:

Mmm, amazing how quickly elation turns to despondency. Most of us get too high based on model runs, - even if they look convincing. Equally we get too despondent at times too. 

Rule of thumb is not to fully believe the models until we get to around T24/48 for good old blightly. Our weather is so much more affected by a multitude of variables compared to a large continental landmass.

The back edge snow predicted by GFS for Tues/Weds is not floating my boat as even if it does happen, it will be falling on relatively warm ground/grass that will already be wet from the rain that is likely to precede it. Hardly a recipe for low level settling!

happened here around 6pm last night temporary whiteout, has to be heavy though

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1 minute ago, I remember Atlantic 252 said:

happened here around 6pm last night temporary whiteout, has to be heavy though

yes it can happen, but not as likely as falling on frigid, dry ground.

Anyway, I think the 12z's will bring some optimism now that expectations have been markedly lowered again!

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The overall trend for the next week remains below average with the exception of Shetland where it looks to be marginally above average

ANOM2m_mean_europe.thumb.png.05dd7dbbcb809804cacdbd2e24be6507.png

Something a bit milder in the north by D7?

ANOM2m_trend_europe.thumb.png.9ae593c1f802b526ca8d4884dcd1c766.png

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I don't think we should give up on next weeks easterly just yet, I quite understand how recent runs of the ECM and GFS have made many disappointed, but this complicated picture for next week has still not been decided and I would not be surprised at all if we get a flip back to an easterly again very soon  - But perhaps more watered down initially from what GFS was showing yesterday. Also the further outlook is still a cold or very cold picture !  

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6 minutes ago, edinburgh_1992 said:

You'd be surprised, I lived for a few years (2008-2013) not far from Varese. It snowed every winter, definitely a lot more than in Scotland. 

North Western Italy has a peculiar climate, snow usually comes with southern/south-western air currents. Due to it being surrounded by the Alps, the cold air gets "trapped" and it takes a lot to kick it out. So as a milder and wetter airmass moves over the area from the Mediterranean, it almost always falls as snow. And the snowfall is usually heavy and persistent too.

There are very rarely disruptions even with 10-20cm snowfalls. Roads are immediately cleared and salted and smaller snow ploughs clean all the paths. Major disruptions are very rare, unlike in the UK. 

Yes, and when cities like Varese get 20cm, up in them mountains there can be 3 foot of snow or more, they usually sort it out pretty quickly I must say. Central/southern Italy do well with the lake effect off the Adriatic of course totally different from what they call the cold cushion of the Po Valley. 

I was out there one winter and it had not snowed properly yet, it was mid January, this elderly lady said to me that it's going to snow, I said to her, how do you know that, nothing is forecast, she said "It always snows, sooner or later". Well it started as we went in February, and snowed on and off all month long with very cold temps, I always remembered that, when it snows in NW Italy we often do ok over here as well for some reason, Genoa Lows help of course.

 

I'm really looking forward to the 12z runs to see how much the low heading towards Italy can correct north, they have had a lot of near misses like us over there in the North West of Italy this winter so far, surely they are not going to miss out again? And I sincerely hope that we don't miss out again over here.

 

 

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Has anyone trawled out the 06Z NAVGEM yet? 😲😆😆

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2 minutes ago, Steve Murr said:

Has anyone trawled out the 06Z NAVGEM yet? 😲😆😆

It’s a cracker Steve! 😂

 

2B57E556-6916-40FF-9088-4130F9CDA971.png

Edited by danm
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8 minutes ago, Steve Murr said:

Has anyone trawled out the 06Z NAVGEM yet? 😲😆😆

Steve you still seem pretty chilled lol . How do you see this one going and if we don’t get the first chance what about the chances after ? 

Thanks 

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5 minutes ago, Daniel Smith said:

 

BTW. The CMA has arguably been the most consistent out of every single model..

CMA.thumb.png.4dfbab3bed2b1cd8f6940d1159d47126.png

Consistent in producing these 'juicy' charts one week or so away, yes. But whether it will prove to be consistently correct re the weather for next w/e?? Well, we'll just have to wait and see.

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Navgem has got this cold north easterlys end next week ..

B037FA97-3893-4C0F-A6BC-B9EA92691C42.png

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I don't think it's over just yet. NAVGEM and icon both not too bad at 6z. UKMO has a route to cold at 144.

You never know, maybe there is just enough time for another big twist?

 

 

Edited by The Eagle
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13 minutes ago, Daniel Smith said:

Right. Now that I'm home and I've had a proper look over everything it's not as bad as initially thought.

ECM clusters show the OP was in the minority cluster which is good news. Cluster 1 isn't great but it's a damn site better than the Op was. Cluster 2 is our nirvana charts before everything went belly up.

CLUST.thumb.png.2292bf35020365656e89744e70f64e42.png

35% support for cluster 1, 33% support for cluster 3. 

With such a large spread in solutions you may as well forget what the ensemble means are showing because they'll be more watered down than a pint of Fosters.

ensemble-tt6-london.thumb.gif.1289bf7afccbcf7c8a9cb625b3ff60cf.gif

The mean remains below 5c for the entire run. EC was clearly on the warmer side of the suite, GFS on the cooler side out in FI. Incredibly finely balanced and could easily swing back towards the charts we were seeing over the last couple of days.  

BTW. The CMA has arguably been the most consistent out of every single model..

CMA.thumb.png.4dfbab3bed2b1cd8f6940d1159d47126.png

Clusters 2 and 3 in particular look great for EA& the SE atleast and chances of it swinging back to benefit us all still. I for one am remaining optimistic. Remember guys this was always expected to be a slow burner 😉

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11 minutes ago, MattStoke said:

Doesn't matter how wet ground is. Snow will settle so long as its cold enough. So many times I've seen hours of torrential rain with several inches of heavy snow then settling onto the soaked ground.

Heavy being the operative word.

The front looks pretty active on GFS for Tues, so could be a good test of your theory Matt (which I don't disagree with)

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1 minute ago, Runcible Spoon said:

Heavy being the operative word.

The front looks pretty active on GFS for Tues, so could be a good test of your theory Matt (which I don't disagree with)

Personally I'm more interested in the showers following. A NW flow normally brings snow to my location and the GFS shows a potential Cheshire Gap streamer along with quite a lot of showers across England and Wales. I normally find the GFS is quite good at picking up these streamers. 

GFS does show a decent spell of back edge snow from that front but the ECM doesn't show any. Different timings in regards to ho quickly the cold air undercuts from the north west. 

Will be interesting once it starts to get into range of the high resolution models, in about 24 hours time.

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5 minutes ago, The Eagle said:

I don't think it's over just yet. NAVGEM and icon both not too bad at 6z. UKMO has a route to cold at 144.

You never know, maybe there is just enough time for another big twist?

It's made even more difficult by having three (at least!) major players to think about. Take away (for a moment) the Atlantic and Arctic/Scandi ridges, and we're left with an amorphous blob of circulating Continental LP centres, any one of which might swipe, at least, EA and the SE - or miss the UK entirely...?

Add in the other two players and it looks like something akin a 'three body problem': impossible to solve precisely?

Just keep your eyes glued to the nearest lamppost!:santa-emoji::cold::yahoo:

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Big snow event as front comes in to colder air ..

6CC549EF-2731-4412-AB53-72CEB42DE3F5.jpeg

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Just now, abbie123 said:

Big snow event as front comes in to colder air ..

6CC549EF-2731-4412-AB53-72CEB42DE3F5.jpeg

Those charts massively over-do the snow. APERGE/ICON far more humbling..

APERGE.thumb.gif.22633e3a3e0582a1835707deceb27423.gif

and ICON

ICON.thumb.gif.2d81f1a79b77e4b51815f1235e355b2c.gif

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26 minutes ago, Daniel Smith said:

Right. Now that I'm home and I've had a proper look over everything it's not as bad as initially thought.

 

Good post Daniel, and I agree with pretty much all of it.  It's not over until the fat lady sings on the 12z output.  And even if the first bite at the cherry is sour, and this might well happen, what follows is still of much interest.  

What might we look for on the 12s?   First, and only by virtue of it being the first out, ICON building on the 6z output and pivoting to the Easterly.  If that happens we can breathe for half an hour!

Before the key moment at about 4.05pm when we find out if UKMO holds or folds.

I'm putting that at about 35% probability it holds.  If it comes off great, though!

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6 minutes ago, Runcible Spoon said:

ARPEGE got Tues/Weds front as a mainly rain affair

That model is so poor. It gave me and large parts of England a full on snow even earlier in the winter, and there wasn't a flake away from the hills. Often way off on temperatures too. It's pretty useless.

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