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DEW
  • DEW
  • Advanced Member
07 January 2023 08:26:21
In week 1, WX charts keep the focus of very cold air over Russia with steep temp gradient to the Polish border; west of that is still well above norm for the time of year. In week 2, that focus doesn't break up as much as shown yesterday, and W Europe becomes cooler, especially away from coasts and in mountainous areas.

GFS Op includes a N Atlantic jet which has strengthened over the last few days, to start with waving first S then N of Britain, but interestingly from about Fri 20th beginning to buckle which may usher in a change of pattern. The synoptics however look much like they did yesterday with W-lies augmented from time to time by deeper LPs (Sun 8th 955mb Rockall, Wed 11th the same) but calming down with ridge of HP from Sun 15th. This has backtracked from last night's output which showed LPs much further south and a NW-ly regime. Then to match the jet above, Thu 19th sees LP established 980mb Sweden with an elongated N_S trough sinking S-wards, by Mon 23rd centred 1010mb Belgium, NE-lies for S Britain, and the beginnings of a Scandi HP.

ECM does run the LPs further S; Wed 11th 970mb N Scotland, 970mb Fri 13th Hebrides, and by Sun 15th HP stays out in the Atlantic and LP 970mb N Sea with NW-lies.

GEFS up (most likely 11th and 16th) and down but mean mostly close to norm and some rain for all areas at various times. The Op is a dramatically cold outlier from Thu 19th; snow row figures for the Highlands also start to increase.
War does not determine who is right, only who is left - Bertrand Russell

Chichester 12m asl
Jiries
07 January 2023 08:28:29

one can only hope something gives to break up this endless dross. Following the (epic for here, bone dry for most) cold spell, it’s been wall to wall Atlantic garbage. Indeed Moomin’s much mocked “3-4 weeks of raging zonality” might prove to be a understatement. 

Originally Posted by: Downpour 



We been on raging zonality since 18th Dec so Moomin was correct as now it 3 weeks and no end of sight but massive blessing for heating costs much down this month.  I checked Toronto and it still mild with low to mid single plus digit when by now suppose to be -1 and -10 at night on average. My cousin told me it been mild most of the time.  Question why we still have raging zonality and PV sitting in wrong place if still mild in Toronto? If mild there we should be looking at cold and snowy by then. 
Brian Gaze
07 January 2023 08:43:27

Brian will you start a new Model Output thread at some point? - just wondering?

end of the 18z Op Run: 
Notice the Siberian High moving north westwards?

UserPostedImage






 

Originally Posted by: tallyho_83 



Normally after 50 pages. 
Brian Gaze
Berkhamsted
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dagspot
07 January 2023 09:24:11

If mild there we should be looking at cold and snowy by then. 

Originally Posted by: Jiries 


Is that the case?
Neilston 600ft ASL
MBrothers
07 January 2023 09:28:28

Is that the case?

Originally Posted by: dagspot 


sounds a very simple format 😂
moomin75
07 January 2023 09:31:21

one can only hope something gives to break up this endless dross. Following the (epic for here, bone dry for most) cold spell, it’s been wall to wall Atlantic garbage. Indeed Moomin’s much mocked “3-4 weeks of raging zonality” might prove to be a understatement.

Originally Posted by: Downpour 

Experience tells me that when a Zonal spell sets up in the North Atlantic, it can take weeks, or even months, to shift.

Hence why I felt we were on the cusp of a long Zonal spell.

​​​​​​​I've a feeling it may blow itself out by February, but we have a lot of water to go under the bridge before we settle down again.  
Witney, Oxfordshire
100m ASL
doctormog
07 January 2023 09:47:49
One look at the FI GFS 00z op run clearly highlights the futility of guesses at our weather a couple of weeks in advance. The fact that the 06z op run (out in the coming hour) for the same time may be completely different emphasises this even further.
briggsy6
07 January 2023 10:22:47
According to my Collins Weather guide February is a drier month on average than January (for London at least) so reasons to hope for an improvement in our weather - though it might be a few weeks until we see any change.
Location: Uxbridge
ballamar
07 January 2023 10:24:14

One look at the FI GFS 00z op run clearly highlights the futility of guesses at our weather a couple of weeks in advance. The fact that the 06z op run (out in the coming hour) for the same time may be completely different emphasises this even further.

Originally Posted by: doctormog 



But Moomin said winter wouldn’t come back until at least first week of Feb. Models must be wrong thought it was safe to not look at Jan
doctormog
07 January 2023 10:36:57

But Moomin said winter wouldn’t come back until at least first week of Feb. Models must be wrong thought it was safe to not look at Jan

Originally Posted by: ballamar 



His guess may be right and time will tell as it has done with his previous multi-week guesses over the past year. The point is that the guess is based on current conditions, climate averages and psychology not model output. I would be as misguided to say with confidence that he will be wrong about weeks of zonal conditions as he would be to state with absolute confidence that is what will happen. 

Wintry weather may return this month, at the start of February or not all this season. In early January it is impossible to say which will be the case.

Our planet’s weather is so complicated and our little group of islands’ weather affected by so many factors, many local others global, that it is impossible to say what will happen with any real confidence beyond a week or so. Yes, we get hints and patterns but that’s all they are. We can all use the climate norms or averages or prevailing Atlantic weather to make a guess and most times we would be right but it doesn’t really make it model analysis.

The top researchers in the area with the best equipment and access to data understand the limitations and always caveat the outlook beyond a certain time period and issue probabilistic forecasts. Some could learn from that. With probabilities even less likely scenarios do occurs and hopefully when that happens we all learn a little from it.
ballamar
07 January 2023 10:39:42

His guess may be right and time will tell as it has done with his previous multi-week guesses over the past year. The point is that the guess is based on current conditions, climate averages and psychology not model output. I would be as misguided to say with confidence that he will be wrong about weeks of zonal conditions as he would be to state with absolute confidence that is what will happen. 

Wintry weather may return this month, at the start of February or not all this season. In early January it is impossible to say which will be the case.

Our planet’s weather is so complicated and our little group of islands’ weather affected by so many factors, many local others global, that it is impossible to say what will happen with any real confidence beyond a week or so. Yes, we get hints and patterns but that’s all they are. We can all use the climate norms or averages or prevailing Atlantic weather to make a guess and most times we would be right but it doesn’t really make it model analysis.

The top researchers in the area with the best equipment and access to data understand the limitations and always caveat the outlook beyond a certain time period and issue probabilistic forecasts. Some could learn from that. With probabilities even less likely scenarios do occurs and hopefully when that happens we all learn a little from it.

Originally Posted by: doctormog 


was hoping you had detected my sarcasm !
Gusty
07 January 2023 10:40:07

Question why we still have raging zonality and PV sitting in wrong place if still mild in Toronto? If mild there we should be looking at cold and snowy by then. 

Originally Posted by: Jiries 



That is because there is a strong zonal (west to east) hemisperical northern jet at the moment with relatively small amplification keeping the very cold air bottled up over the higher latitudes.
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Jiries
07 January 2023 11:03:59

That is because there is a strong zonal (west to east) hemisperical northern jet at the moment with relatively small amplification keeping the very cold air bottled up over the higher latitudes.

Originally Posted by: Gusty 



Yes looking at Canada weather map it show the northern part of the jet are sub -10C temps while southern side of the jet where Toronto sit is mild side.  I remember seeing the USA weather channel showing the jet stream goes straight from west to East at times but mostly in waves more often than straight lines.
Downpour
07 January 2023 11:14:02

Experience tells me that when a Zonal spell sets up in the North Atlantic, it can take weeks, or even months, to shift.

Hence why I felt we were on the cusp of a long Zonal spell.

I've a feeling it may blow itself out by February, but we have a lot of water to go under the bridge before we settle down again.  

Originally Posted by: moomin75 



agreed. And a good shout by you. Credit where it is due. 
Chingford
London E4
147ft
Downpour
07 January 2023 11:17:45

His guess may be right and time will tell as it has done with his previous multi-week guesses over the past year. The point is that the guess is based on current conditions, climate averages and psychology not model output. I would be as misguided to say with confidence that he will be wrong about weeks of zonal conditions as he would be to state with


absolute confidence that is what will happen. 


Wintry weather may return this month, at the start of February or not all this season. In early January it is impossible to say which will be the case.

Our planet’s weather is so complicated and our little group of islands’ weather affected by so many factors, many local others global, that it is impossible to say what will happen with any real confidence beyond a week or so. Yes, we get hints and patterns but that’s all they are. We can all use the climate norms or averages or prevailing Atlantic weather to make a guess and most times we would be right but it doesn’t really make it model analysis.

The top researchers in the area with the best equipment and access to data understand the limitations and always caveat the outlook beyond a certain time period and issue probabilistic forecasts. Some could learn from that. With probabilities even less likely scenarios do occurs and hopefully when that happens we all learn a little from it.

Originally Posted by: doctormog 



Well he made a forecast before Christmas which looks like being spot on. For that he surely deserves some credit, after all, members are quick to attack him when he is proved wrong. 

This wet zonal dross is not what many (any?) of us want to see, but one has to say he looks to have called it correctly. 
Chingford
London E4
147ft
doctormog
07 January 2023 11:23:46

Well he made a forecast before Christmas which looks like being spot on. For that he surely deserves some credit, after all, members are quick to attack him when he is proved wrong. 

This wet zonal dross is not what many (any?) of us want to see, but one has to say he looks to have called it correctly. 

Originally Posted by: Downpour 



The fact that this is what you take as the key message from my post shows you don’t understand what I wrote.

Ok, I can guess the next two months will have above average temperatures and summer will be warmer than the LTA. None of this is model output analysis. 

As we are in the model output thread, what is your take on the last couple of GFS op runs for late January, especially in terms of the jet stream profile over N America and consequently N Europe? It would be helpful to see your analysis in this particular point especially given the meridional nature of the last two consecutive runs.
idj20
07 January 2023 11:31:29

Yes looking at Canada weather map it show the northern part of the jet are sub -10C temps while southern side of the jet where Toronto sit is mild side.  I remember seeing the USA weather channel showing the jet stream goes straight from west to East at times but mostly in waves more often than straight lines.

Originally Posted by: Jiries 



I think I know what you are getting at. I tend to associate strong zonal straight-line jet stream profiles being the result of extensive deep cold digging well south over the USA, that would then lead to regular wet and windy conditions here at the UK via Atlantic low pressure systems one after the other. Currently it doesn't seem to be THAT cold over there (apart from obviously Canada) and yet we're still stuck under this long-fetched maritime-type zonal set up with little change expected for the foreseeable future. I think the wind profile at the stratsopheric level is the main culprit where it is still very westerly zonal-like around the mid-latitude zone. Or perhaps I'm talking out of my backside as usual.
Folkestone Harbour. 
Brian Gaze
07 January 2023 11:31:55

Well he made a forecast before Christmas which looks like being spot on. For that he surely deserves some credit, after all, members are quick to attack him when he is proved wrong. 

This wet zonal dross is not what many (any?) of us want to see, but one has to say he looks to have called it correctly. 

Originally Posted by: Downpour 



Credit should go to those who are consistently doing well at medium range. Therefore, I wouldn't praise Moomin for this specific forecast, but equally I wouldn't admonish him if it was wrong. Look at the Met Office medium term outlooks as an example. They change frequently and illustrate the limit of what is possible. We need to accept those limits and not buy into extravagant claims. For example, I read comments a couple of weeks ago saying that "experts" on another forum were explaining why a cold January was a shoe-in.  
Brian Gaze
Berkhamsted
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"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
doctormog
07 January 2023 11:34:10

I think I know what you are getting at. I tend to associate strong zonal straight-line jet stream profiles being the result of extensive deep cold digging well south over the USA, that would then lead to regular wet and windy conditions here at the UK via Atlantic low pressure systems one after the other. Currently it doesn't seem to be THAT cold over there (apart from obviously Canada) and yet we're still stuck under this long-fetched maritime-type zonal set up with little change expected for the foreseeable future. I think the wind profile at the stratsopheric level is the main culprit where it is still very westerly zonal-like around the mid-latitude zone. Or perhaps I'm talking out of my backside as usual.

Originally Posted by: idj20 



Yes it is just now, but there are signs that may change (in some of the recent output GFS and ECM ensemble data). Time will tell.
idj20
07 January 2023 12:00:39

Yes it is just now, but there are signs that may change (in some of the recent output GFS and ECM ensemble data). Time will tell.

Originally Posted by: doctormog 



I notice the stratsopheric polar vortex at the 10 hpa and 30 hpa levels being put under stress later on this month, but the wind profile is still largely westerly over Europe. Like you say, we shall see. 
Folkestone Harbour. 
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