Model output discussion - The Hunt For Cold

[jam]

33 minutes ago, Bartlett High said:

Isn't this all happening a little too early in the season/

Well there’s not a lot that we can do either way ... fanisating watching however 

[Cheshire Freeze]

The issue is that year on year some people don't learn. 

Cast your mind back to November 2016- everyone was getting giddy about a 'disorganised vortex' and blocking- even the Metoffice were going all in on a cold December. The issue was, like now, there were an abundance of factors which suggested mild- not least the fact the zonal winds in the strat had reached heady figures. The only thing that kept the trop PV in a ragged state through November that year was the strat-trop disconnect. Towards the middle of that month, the modelled Greenland high pressure failed to assert and was toppled...from that point I knew it was game over- and it was. The strat and trop coupled.

All the abuse I received that year when I was warning people not to get excited...Believe me it would be so much easier to sit here telling everyone how cold it is going to get and how many snow events we are going to be seeing, lapping up the 'likes'...but I'm a realist I'm afraid. 

It would be ludicrous to suggest winter is over in October...my post was merely suggesting we need to keep a blocked pattern going as long as possible in the locations that count (which won't necessarily benefit the UK in terms of cold right at this moment). I feel a key requisite this year will be a Canadian warming early December.

Edited October 21, 2018 by CreweCold

[Rocheydub]

Indeed Crewe, I was one of your supporters that year, I was berated for it too. I agreed with you, but got slammed for it. Same goes for this year, need to keep the blocking in place in the NH views!

[coldwinter]

9 minutes ago, CreweCold said:

 I feel a key requisite this year will be a Canadian warming early December.

Unfortunately Canadian warmings are as rare as hens teeth! Key thing for me to watch is the development of the scandi high, and fro pressure to remain high in scandi/Siberia to get some wave activity going and keeping the vortex in check. 

[Cheshire Freeze]

Just now, coldwinter said:

Unfortunately Canadian warmings are as rare as hens teeth! Key thing for me to watch is the development of the scandi high, and fro pressure to remain high in scandi/Siberia to get some wave activity going and keeping the vortex in check. 

Yes at the very least! That's what I'm looking towards, HP towards that way. It's the key for me as we enter November.

[Skullzrulerz]

So it seems the ECM is the best case scenario for cold fans so far however I don't like these changes of it happing I would expect a half way house of some kind ? Like it mostly happens right ?

[Chesil View]

16 minutes ago, CreweCold said:

The issue is that year on year some people don't learn. 

Cast your mind back to November 2016- everyone was getting giddy about a 'disorganised vortex' and blocking- even the Metoffice were going all in on a cold December. The issue was, like now, there were an abundance of factors which suggested mild- not least the fact the zonal winds in the strat had reached heady figures. The only thing that kept the trop PV in a ragged state through November that year was the strat-trop disconnect. Towards the middle of that month, the modelled Greenland high pressure failed to assert and was toppled...from that point I knew it was game over- and it was. The strat and trop coupled.

All the abuse I received that year when I was warning people not to get excited...Believe me it would be so much easier to sit here telling everyone how cold it is going to get and how many snow events we are going to be seeing, lapping up the 'likes'...but I'm a realist I'm afraid. 

It would be ludicrous to suggest winter is over in October...my post was merely suggesting we need to keep a blocked pattern going as long as possible in the locations that count (which won't necessarily benefit the UK in terms of cold right at this moment). I feel a key requisite this year will be a Canadian warming early December.

Indeed you did take a lot of abuse Crewe. You were right to be wary.

I am wary at the moment too, flashy winter synoptics at the end of October/start of November do not necessarily signal a cold and snowy winter. I remember a snowy guy Fawkes night in 1980. Even Jersey had snow but the winter that followed was notably unremarkable. This time might be different but we won,t have any inkling of that for another 3 or 4 weeks yet.

[sundog]

26 minutes ago, Broadmayne blizzard said:

Indeed you did take a lot of abuse Crewe. You were right to be wary.

I am wary at the moment too, flashy winter synoptics at the end of October/start of November do not necessarily signal a cold and snowy winter. I remember a snowy guy Fawkes night in 1980. Even Jersey had snow but the winter that followed was notably unremarkable. This time might be different but we won,t have any inkling of that for another 3 or 4 weeks yet.

End of Oct and start of Nov 1988 was on the cold side too. Winter 88/89 was a terrible one of course.  You just never know how things will pan out. 

[Frosty.]

Great looking Ecm 12z ensemble mean tonight if you're a coldie..

[andymusic]

38 minutes ago, sundog said:

End of Oct and start of Nov 1988 was on the cold side too. Winter 88/89 was a terrible one of course.  You just never know how things will pan out. 

Pattern matching can be a useful tool but rarely pans out - each winter is pretty much as individual as the next in our small lifetimes although no doubt over millions of years there may well have been some "duplicates" I've no doubt

[BlueHedgehog074]

Not perfect, but the 12Z NAVGEM gives a reasonable go at toppling the Atlantic ridge into Scandinavia.

Still no match for the 12Z ECMWF, but provides a chilly Easterly flow over Central, Southern and some Northern parts of the UK.

Could do with a more favourable angle to that Low Pressure to the West of Iceland (being more negatively tilted) so there would be no danger at all of the Lows piling of top of the Scandinavian ridge, or it getting knocked too far East. But at the same time, doesn’t look like it would bring an immediate return to the Atlantic and it’s Westerly/South-Westerly winds. Plus the Low over Northern Spain would probably help to keep the Scandinavian ridge propped up. Not too bad overall.

While there is no guarantees a Scandinavian ridge will result from this Northerly setup (but there is at least some support), do feel it would make a nice change from those times where a Northerly just topples and the Atlantic quickly gets back in! 

Edited October 21, 2018 by DiagonalRedLine
Making few odd corrections

[Met4Cast]

18z GFS is simply stunning

[Mike Poole]

What post northerly?

well the GFS 18z has the strongest signal yet from the runs I've seen for a Scandi high, here at T204:

Jet stream at same time:

Small steps, need the strat to get on board at some point, though. No immediate hurry.

Edit, by the way, anyone else think the T240 chart has an air of implausibility about it?

Edited October 21, 2018 by Mike Poole

[Kirkcaldy Weather]

18z has the scandi high better placed with a band of rain off the east coast moving in possibly turning wintry  

[Kirkcaldy Weather]

8 minutes ago, Mike Poole said:

 

Edit, by the way, anyone else think the T240 chart has an air of implausibility about it?

as we have seen with the upcoming northerly and with scandi/greenland highs in the past some of the models are far too keen to break them down quickly, fingers crossed the scandi high can develop and hold back the lows (slider lows possibly?)

[nick sussex]

Can we turn the clock forward a month !

A great set up just a little bit too early . The models are in very good agreement for the initial cold snap .

The  Scandi high development looks more likely today as the PV looks weak with the main energy heading se to the west of the UK .

Overall it looks like a Canadian style change from warm autumnal conditions to cold bypassing the more mediocre bit in the middle . Some early season snow for higher elevations in the north , still not convinced of anything more widespread given how early in the season we’re seeing this good set up.

I wouldn’t look further than day 8 , a lot going on and the models look a bit of a mess after that point .

 

[Derecho]

3 hours ago, Broadmayne blizzard said:

Indeed you did take a lot of abuse Crewe. You were right to be wary.

I am wary at the moment too, flashy winter synoptics at the end of October/start of November do not necessarily signal a cold and snowy winter. I remember a snowy guy Fawkes night in 1980. Even Jersey had snow but the winter that followed was notably unremarkable. This time might be different but we won,t have any inkling of that for another 3 or 4 weeks yet.

Yes I think in 2016 people thought it was certain we would be getting cold synoptics because all the longer range forecasts were indicating cold but that counts for nothing until we get into medium range, it's just an inkling.

I think last winter was different because we had a big SSW event and this has a plausible mechanism for causing northern blocking.

Saying that though a strongly negative NAO in November does seem to improve our chances of cold in its first half but not by a huge amount. I also look out for cold shots reaching the SE US and very mild air getting to Newfoundland and Greenland.

SSTs are also worth keeping an eye on, here are a comparison between milder winters and their November SSTs 

Milder winters

                          2015                                                         2013                                                         1994                                                          2011

  

Colder ones

                         2012                                                           2010                                                        1996                                                            1995                                                

   

 

From the examples it seems as though warmer then average SSTs around the east of Newfoundland, around Greenland and the tropical north atlantic but it isn't clear cut.

What at 2018? Here is the picture from the latest SSTs....



Seems like an SST profile that would favour a more westerly jet so the southerly flows in the Central North Atlantic region would be nice. As would be some cold pooling in the SE US/ Gulf of Mexico which is what is happening this week.

So the northerly next weekend is welcome IMO. 18Z not much different from the 12z upto the medium range.

 

Edited October 21, 2018 by Quicksilver1989

[Paul_1978]

3 hours ago, CreweCold said:

The issue is that year on year some people don't learn. 

Cast your mind back to November 2016- everyone was getting giddy about a 'disorganised vortex' and blocking- even the Metoffice were going all in on a cold December. The issue was, like now, there were an abundance of factors which suggested mild- not least the fact the zonal winds in the strat had reached heady figures. The only thing that kept the trop PV in a ragged state through November that year was the strat-trop disconnect. Towards the middle of that month, the modelled Greenland high pressure failed to assert and was toppled...from that point I knew it was game over- and it was. The strat and trop coupled.

All the abuse I received that year when I was warning people not to get excited...Believe me it would be so much easier to sit here telling everyone how cold it is going to get and how many snow events we are going to be seeing, lapping up the 'likes'...but I'm a realist I'm afraid. 

It would be ludicrous to suggest winter is over in October...my post was merely suggesting we need to keep a blocked pattern going as long as possible in the locations that count (which won't necessarily benefit the UK in terms of cold right at this moment). I feel a key requisite this year will be a Canadian warming early December.

The problem could have been a perception of hubris Crewe? But yes I completely agree, I’m not getting particularly excited in October, but nonetheless the patterns are great to see, however long they may last.

[Kirkcaldy Weather]

P4 ramps up the scandi high and gets a mega cold pool towards Russia which would be great for the snow cover    

PV non existent on P11 with lots of northern blocking and cold going into Russia etc building snow cover   

P12  

northerly still looking good 

[BlueHedgehog074]

A little area of -10*C 850 hPa temperatures scraping past the Western edge of Scotland on the GFS 00Z run for early Saturday at 123/126 hours.

That wouldn’t be too out of place in November (even if those -10*C 850 hPa’s get mixed out quickly).

No real signs of any watering down of the Northerly later this week on the GFS.

And with some kinks in the flow, I suspect there could be some more organised areas of showers or longer spells of precipitation at times, some of which would be wintry over the hills. But perhaps the air mass being cold enough at times for something wintry to some lower levels too. More especially the further North you are.

Having something like this occur about a month later would perhaps still be ideal. But it’s something to get the cold weather fans rock and rolling!

Edited October 22, 2018 by DiagonalRedLine

[Rayth]

Ecm @ 192hrs has very cold air fondling the shetlands !

[Summer Sun]

No change overnight on the 7-day tend with western Europe going into an early cold snap Spain and Portugal could be substantially below average for a time

[ICE COLD]

ECM day 10 chart is a lovely position to be in as we enter November. The vortex is in tatters. 

[northwestsnow]

EC looks a cold run this morning.

Temps really struggling through next weekend and into the following week, for sure time to dig out the woolies !!

I suspect we will see a ridge thrown over or just to the north of the UK post day 10, with the jet to the south of the UK.

[Man With Beard]

The weekend firming up more and more on the cold snap

I suspect the ECM is overdoing heights into Scandi after that, time will tell, but I think more likely that the incoming low at D7/D8 will be a direct hit on the UK rather than passing to the south. Scotland could see significant snow from this second event if it can draw in enough cold from a freezing Scandinavia, though cold rain probably the favorite considering the time of year.