Model output discussion - The Hunt For Cold

[Don]

8 hours ago, bluearmy said:

Indeed ...... the drift away from an early start to winter on the model evident on Tuesday and now confirmed (even more so) on this latest run. Whilst many will quite rightly say that beyond week 3 this model is of little use, up until this week, the 46 was syncing well with the seasonal ......that would be the message I would be taking from the past two runs ..... next week sees the next seasonal output and those expecting a front loaded season will be watching expectantly, given what has gone before on the model ........

Could see the EC seasonal output make a move towards the GLOSEA5 then and dare I say it, the dreaded CFSv2!

Edited October 26, 2018 by Don

[jethro]

This hunt for cold.....it's ok, I've found it, it's outside my house, you're all welcome to come round and share it.

I could do with the collective heat of a posse, it's feeling blinking cold in that wind. We must all be certifiably insane to yearn for more and much colder than this, bonkers.

[Mike Poole]

D'oh I've just posted this in the wrong thread, reproducing here as best I can:

I've detected from just a few posters a waning of enthusiasm for a front loaded cold winter, so I'd like to take stock just before this brief northerly and unseasonal blast hits this weekend. 

It matters not a jot whether this persists or is replaced by milder wetter weather, as far as the bigger picture of early winter is concerned.  

 

The models still point to a disconnect between the trop and strat vortexes, with the strat vortex organised and modelled to become less so, and the trop vortex disorganised and not modelled to become more aligned with the strat. GEFS zonal mean zonal wind in the strat  as follows:

Last months Met Office contingency planners noted an unfavourable SST pattern for UK cold, but it has dissipated since then, pattern today first v last month:

SST profileS look to me to be neutral-ish re UK winter weather now.  Having viewed the GloSea5 output earlier, on balance I would expect the next 3 month MO output due Monday? will slightly tilt in favour  of cold, but not massively so, baby steps...

Finally people mention the CFS, it is meaningless to study one run from this model, so for a balanced view here are the last 8 runs starting yesterday's 18z, for sea level pressure mean anomaly during December:

Only the last one looks horrendous, maybe this model is coming on board.  interesting times ahead for sure!

Edited October 26, 2018 by Mike Poole

[Walsall Wood Snow]

I have to agree that there's certainly no need for despondency at this early stage. After all how many really cold Winters got going in early November anyway. Not any in the 20th century anyway that I'm aware of. You may have heard the old saying of 'Ice in November to bear a duck, the rest of the Winter will be rain and muck'. Not strictly true I'm sure but I think there's a few examples of very cold November's which were followed by Winters with less impressive cold a anomalies at least. One example of a very cold November that comes to mind though that was followed 'eventually' by a very cold Winter month, would be 1985. And although Feb 86 was the coldest Feb since 1947, Dec 85 was very mild for the most part and even Jan 86  wasn't very cold. Also Nov 93 wasn't followed by any very cold months the following Winter, even if Feb 94 could be described as a bit cold at best. Next we have Nov 2010 which of course didn't turn particularly cold until near the end and although it was followed by the very impressive December, by the New Year the best of it was behind us and Feb 2011 was a very mild month. 

So in summary it seems at least for the most part, very cold November's are seldom followed by very cold Winters in the main DJF quarter and quite often very cold late Autumn/ Winter months are often accompanied along with pretty mild ones as well. I think late December up to mid January really is the typical landing zone  for more evenly spread cold Winter weather, so anytime around then is best if it's cold weather until at least March you're looking for.

[Allseasons-Si]

That's a very naughty chart from the ecm,a nice spirt of high preasure into western europe

on the other hand there are nice height's heading into Greenland from both sides,would love to have seen the next frame,cut off low?

Edited October 26, 2018 by Allseasons-si

[Kirkcaldy Weather]

ECM and GEM pretty similar at 240h, more unsettled for us especially on the ECM but higher pressure trying to link from scandi - Greenland

   

[blizzard81]

Ecm 12z looks synoptically very similar to early November 2009. Let's see where we go from there. 

[Derecho]

38 minutes ago, blizzard81 said:

Ecm 12z looks synoptically very similar to early November 2009. Let's see where we go from there. 

It looks like a pretty cyclonic setup but with temperatures probably not too far from the average for early November. A potential uncertainty to throw in the mix is tropical storm Oscar which may encourage a mid Atlantic ridge.

Lets see what it throws up! It will probably form as a tropical storm tomorrow.

[ANYWEATHER]

Evening! A very unusual pattern for late October ,as regarding cold, These charts would not be out of place during January! As the seas around our shores are relatively mild , lots of convection will happen ,,,again was not predicted by the BBC and Likewise ...I think places lie Broadway Hill near Evesham or the Tower , Malvern Hills could receive a dusting of snow , in the next 24 to 48 hours time ..and any high ground in the country ...I think Snow over the Pennines will make news headlines this weekend...

[Mike Poole]

GFS 12z and the parallel FV3 both end their runs with powerful blocking which will help as we head towards winter proper, anomalies shown below:

The important point being that while the tropospheric pattern is disconnected to the developing stratospheric vortex, a front loaded winter is entirely possible, and model output suggests we've got that until mid November at least, and probably further, what happens after that is unknown and will be interesting to follow, we either need the disconnect to continue or a SSW, but NOT the strat vortex to win out!

[Allseasons-Si]

@Mike Poole

The cpc 500mb height anomoly's for 6-10 and 8-14 days show a robust block to our NE too pumping into the pole,yes we have to endure the southwesterly's for a while but i couldn't care less as long as that block holds in situ

that's a strong block

 

[Allseasons-Si]

The 18z gfs really ramping up tropical storm Oscar in the Alantic and could throw a ridge ahead of it,one to watch.

a spanner in the works as you would say but maybe for the better by sending a ridge into Greenland.

i say this because the stronger the depression the stronger the ridge ahead of it.

[Allseasons-Si]

I know it's Fl but theres our ridge.

Well that ends well,just need a few tweaks

Edited October 26, 2018 by Allseasons-si

[BLAST FROM THE PAST]

I like the ECM and 18z GFS rolling out hint at LPs tracking on southerly trajectory with ridging in Atlantic trying it’s hand again.  Should fail initially  but nice to see the outlook with a retry.  Kitchen sink with colder evolution ever more present latter half...but don’t look for any freeze yet as the pattern won’t hold.....yet.  And don’t hold out for prominent Scandi ridge yet...

 

BFTP

Edited October 26, 2018 by BLAST FROM THE PAST

[kumquat]

We can take the pummeling of relatively benign Atlantic Lows when it leads to this:

Variations on a theme.

Edited October 27, 2018 by kumquat

[JeffC]

9 hours ago, blizzard81 said:

Ecm 12z looks synoptically very similar to early November 2009. Let's see where we go from there. 

Not looked but mid Nov 09 was hellishly wet in the Lake District...Don't want that get again!

[carinthian]

23 hours ago, carinthian said:

Bit of a update this morning. The stalled Baroclinic/Fontal zone across Central Europe really causing some concerns over here. A combination of convective and orographic rainfall from deep layered clouds is expected to be huge, especially in the Southern Alps. Some models showing plus 500ml totals by Tuesday morning. Our snowfall model now churning out some results. On the wider pictures 100cm of fresh snowfall showing in the higher parts of the Swiss Valais Region, however the mix of some very warm air advection making the predictions less reliable further east. Presently in resort no snow is forecast but at 2000m  rain to snow % increases . All a bit of a mess really. The crux is how far the Arctic Front/ Airmass from the NW progresses into the Alps before Re -curving. The short time fine mesh model for snow predictions will almost be loaded with hourly information to get the results we need to know in resort. Longer term view from our experts , still show a robust Siberian block holding and possible strengthening with a stalling jet in the location of Western Europe. Charts from ECM ( below) and GFS sort of show that with the European trough meandering in the vicinity of the British Isles. Long way off though. The main concern from over here is the amount of rainfall , flooding expect in the shorter term. Will keep you updated.

Looking at the very latest fax chart ,think the cold front has now reached its limit into the Northern Alps and a clash of very different airmass now taking place. Cyclonic circulation now in formation over NW Italy along the stalled Baroclinic /Frontal zone. Raining in many parts of the Alpine Regions with some snow in the Northwest Alps including SW Bavaria at about 1400m, further east and south freezing level still above 2000m. Huge amounts of precipitation expected over the next 24 to 36 hours. Keep you updated with developments over here. Not a great day to be about in the mountains.

C

[northwestsnow]

EC seemingly keen to send some energy into Europe by day 10 this morning.

A trend i would like to see continued.

 

[blizzard81]

4 hours ago, JeffC said:

Not looked but mid Nov 09 was hellishly wet in the Lake District...Don't want that get again!

Yes, it was incredibly wet here in the north of England. Lost count how many times I got soaked going to and from work. 

[blizzard81]

13 minutes ago, northwestsnow said:

EC seemingly keen to send some energy into Europe by day 10 this morning.

A trend i would like to see continued.

 

Indeed. Loving the negative tilt to the trough by days 9 and 10. Great looking northern hemisphere view by day 10 which imo promises much cold potential down the line. 

[Methuselah]

I'm not bothered by next week's potential warmth as it has no bearing whatsoever, on long-term prospects. I am with BFTP, as far as the meandering jet goes, so, at this stage in the proceedings, it hardly matters whether meridionality is producing warm southerlies or cold northerlies; it's the buckling itself that matters?

The only way is...whichever way it is!

[summer blizzard]

 

31 minutes ago, blizzard81 said:

Indeed. Loving the negative tilt to the trough by days 9 and 10. Great looking northern hemisphere view by day 10 which imo promises much cold potential down the line. 

Looking at the Euro 0z i am relatively certain that the Euro will not undercut and we'd probably see the high pushed south east at days 11-13. As fantastic as that chart looks in isolation you can see from the day 9 chart that the low is headed north east and will only try sink the block. 

The better setup was from the GFS0z which saw a similar low but moving south east from days 9 to 10..

[blizzard81]

12 minutes ago, summer blizzard said:

 

Looking at the Euro 0z i am relatively certain that the Euro will not undercut and we'd probably see the high pushed south east at days 11-13. As fantastic as that chart looks in isolation you can see from the day 9 chart that the low is headed north east and will only try sink the block. 

The better setup was from the GFS0z which saw a similar low but moving south east from days 9 to 10..

You could indeed be right. I actually think the low would probably stall over the UK. All a little academic at that range though of course. 

[Snipper]

Live 360 webcam at Val Thorens is always worth a look from time to time. http://www.valthorens.com/en/live/livecams--webcams/resort-livecam.550.html

[summer blizzard]

26 minutes ago, blizzard81 said:

You could indeed be right. I actually think the low would probably stall over the UK. All a little academic at that range though of course. 

Yes. On the GFS the core of the high was located south of Moscow whereas on the Euro it was in southern Finland. This meant that the GFS failed in FI because although it got a probable better undercut, it had more high that it needed to lift. 

The above of course explains why most of the time, retrogression ends up failing. So many factors need to come perfectly into place.