Model Output Discussion

[karyo]

Saying that Karyo temps stil lwouldn't be that far from average on the 06z op, and would only need a small shift westwards again to be cold, however I think its hard to ignore the 0z eCM and the GFS both shifting the intial high a little too the east again, its a trend I'm already noting this winter...one of under-estimating the jet, esp outside of 144hrs.

This is certainly a danger with the high pressure scenario. If it was to occur as the operational suggests temperatures wouldn't be far from average on the surface. However, even a slight shift east/southeast would be very mild.

Karyo

[Cecil Hogmanay Melchett]

Here's the mean 500hpa chart at 156hrs and it looks distinctly Bartlett

http://91.121.94.83/modeles/gens/run/gens-21-1-162.png?6

The control run has an easterly as well in FI but not as potent as the parallel run.

http://91.121.94.83/modeles/gens/run/gens-0-1-336.png?6

If its northern latitude based cold you are after that gfs mean looks pretty awful.

[Michael Fishermans Friend]

Well if I was a gambling man and I am I would put my money on that GFS (06z) being more or less correct with some form of blocking to the east without any feed from the east, quite a few of the last Decembers have seen similar scenario's to this with either calm dull conditions or chillier frosty conditions before the weather gets somewhat more mobile again and lets face it pressure has to rise sooner or later and I reckon this is the most likely outcome.

[reef]

That chart from the t168 GEM is actually quite representative of the likely pattern by then. If you were to take into account the background factors and the suggested split in the vortex and -AO then you can see how a colder scenario could emerge. Perhaps you are not doing that and just see it from the usual warming persistence factor pespective that overules every synoptic set up irrespective of the suggestions that the individual background factors and indicators might have?

TEITS amongst others is looking at the actual pattern without being overly focused on any global warming issues and post 1987 UK winter mishaps. The models are influenced by these background factors and telecommunications etc so discussion relating to those is entirely pertinent - irrespective of the eventual outcome, cold or mild.

With all due respect, the models are a prediction tool, theres no way of knowing if they are representative of the likely pattern then or not. Im talking about what the charts are actually showing, not what they 'might' lead to, as that is nothing more than imagination (and indeed nonsense, as the later stages of that GEM run show nothing of the sort). Im not sure what global warming or post-1987 has to do with anything? At the end of the day, the charts are showing something and whether it is now or 50 years ago makes no difference - they're simply not showing a cold spell.

[mushymanrob]

wow! i know im alone here but fi atm is splendid! :blush:

[reef]

wow! i know im alone here but fi atm is splendid! :blush:

It looks distinctedly average to mild and settled, but more importantly dry. Im sure a lot of the people in the North-west would share your sentiment there, it would give a breather from the relentless wet weather. Unfortunately, it looks like a good week of unsettled weather beforehand, assuming it even materialises!

Its not looking too positive at present to be honest for those wanting cold weather. In the first 120 hours of the run those familiar blues and purples are anchored to Greenland with us in mild south-westerlies and the jet roaring across the Atlantic. Temperatures look mild by day and sometimes exceptionally so by night.

[memories of 63]

wow! i know im alone here but fi atm is splendid!

Yes I'm excited about FI in the GEFS Control as well

[karyo]

The met office further update mentions a dry spell in the south for a time but then unsettled again with rain at times. They are not expecting the high pressure to take control across the country or last!

http://www.metoffice.gov.uk/weather/uk/uk_forecast_weather.html

Karyo

[chionomaniac]

With all due respect, the models are a prediction tool, theres no way of knowing if they are representative of the likely pattern then or not. Im talking about what the charts are actually showing, not what they 'might' lead to, as that is nothing more than imagination (and indeed nonsense, as the later stages of that GEM run show nothing of the sort). Im not sure what global warming or post-1987 has to do with anything? At the end of the day, the charts are showing something and whether it is now or 50 years ago makes no difference - they're simply not showing a cold spell.

The thing is reef, a few people who are capable do try and predict what will happen after a reliable period based on good sound reasoning and experience and with the use of similar analogues. Their predictions and suggestions are reasonable based on the evidence put forward. They are looking a little bit further then the models and I would not say that any predictions they make is just their imagination or nonsense.

Why would GP bother otherwise?

[The watcher]

In case this has not been posted before I think this is a excellent link that goes some

way to explaining the the relationships between the GWO, AAM and MJO.

It helped me to get a better understanding on these complex teleconnects.

http://www.esrl.noaa...maproom_new.htm

Plus this one from Ed Berry.

http://www.deepconve...11HPC_Berry.ppt

Thanks very much cooling climate, was looking to learn more on the GWO and AAM and the relationships between these 2 and the Madden Julien Oscillation. I'm also interested in the QBO's relationship aswell and how when one favours a cold setup and the others favour the complete opposite, how this will effect us pattern wise. For instance with the MJO at Phase 7 heading phase 8, the QBO (as GP said yesterday) was going between phases 2/4?. The MJO is trending to a blocking pattern whereas the QBO is in the wrong position and hindering the chances. Very interesting indeed......

[oldsnowywizard]

every year wintertime, i can hear stratos saying that the jet is not in the right position.. at last seems like we dont have to wrry about that scupering any potential cold... anyone heard from stratos? anyone seen the northern arm of the jet recently?

[chionomaniac]

Thanks very much cooling climate, was looking to learn more on the GWO and AAM and the relationships between these 2 and the Madden Julien Oscillation. I'm also interested in the QBO's relationship aswell and how when one favours a cold setup and the others favour the complete opposite, how this will effect us pattern wise. For instance with the MJO at Phase 7 heading phase 8, the QBO (as GP said yesterday) was going between phases 2/4?. The MJO is trending to a blocking pattern whereas the QBO is in the wrong position and hindering the chances. Very interesting indeed......

The Quasi Biennial Oscillation(QBO) is something completely different from the Global Wind Oscillation (GWO) and shouldn't be confused with it. See the first post on the stratospheric thread for an explanation of the QBO.

Edited December 4, 2009 by chionomaniac

[karyo]

The ECM ensembles: http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

show the majority staying mild but there are a few cold solutions as well including the control run!

http://www.cawcr.gov.au/bmrc/clfor/cfstaff/matw/maproom/RMM/phase.Last40days.html

The MJO is continuing it's journey through pahse 7 and it should soon enter phase 8. Moving rather fast!

http://www.cawcr.gov.au/bmrc/clfor/cfstaff/matw/maproom/RMM/phase.Last40days.html

Karyo

[pyrotech]

That chart from the t168 GEM is actually quite representative of the likely pattern by then. If you were to take into account the background factors and the suggested split in the vortex and -AO then you can see how a colder scenario could emerge. Perhaps you are not doing that and just see it from the usual warming persistence factor pespective that overules every synoptic set up irrespective of the suggestions that the individual background factors and indicators might have?

TEITS amongst others is looking at the actual pattern without being overly focused on any global warming issues and post 1987 UK winter mishaps. The models are influenced by these background factors and telecommunications etc so discussion relating to those is entirely pertinent - irrespective of the eventual outcome, cold or mild.

Its ok talking about focusing on Global warming issues, but then you must take in the solar minimum issues too.

Coldest October for many years in states, record in two states. Record cold in Hong kong and India too. Not everywhere has been so warm.

I am not a cold ramper but there are so many influences and Fi is also not a set period in time, that changes with the patterns, sometimes FI is 120hrs some times 240hrs ect. Trends by consistant runs or two major models showing similar in Fi make it interesting enough to comment on, yes it will still often change, normally a down grade but sometimes an upgrade. Funny enough it can be both depending what your hoping for. An upgrade for cold would be a downgrade for someone wanting mild and wet.

GFS still holding on too Cold in Europe at +240 Fi but also looks fairly good with ECM thats whats interesting. One step at a time - Cold Europe then lets see what happens from their.

[The watcher]

The Quasi Biennial Oscillation(QBO) is something completely different from the Global Wind Oscillation (GWO) and shouldn't be confused with it. See the first post on the stratospheric thread for an explanation of the QBO.

Must have got confused with it and the GWO then, but no matter, thanks for sorting me out there Chionomaniac.

[Stu_London]

anyone heard from stratos? anyone seen the northern arm of the jet recently?

His mum only lets him on the computer once a month to enter the CET competition.

I was as suprised as anyone to learn he was only 13.

[SMU]

I dont really take part in the model discussions any more- However things are a tad interesting at the moment-

Apart from the background teleconnection information>> the components of the overall jet strength & location -like the Temp of the stratosphere & negative wind anomaly the reality is we see a chunk of polar vortex energy dropping in towards Eastern Europe ~ around Moscow-

http://www.wetterzentrale.de/pics/MT8_Moskau_ens.png

( Of note was the 06z was an outlier in the mid term )

Most will have noted that over the last few days that the moscow ensembles from the GFS brought in the cold quite quickly, however it was moved back by a couple of days-

The point being here is that the model hadnt even resolved the location of the PV- so whatever we see or saw in FI was irrelevant as you would never be able to assess what the correct solution was - cold or warm-

Move through to today & we are firming up on the how the energy drops into that area & the subsequent flow that develops out of Eastern Europe coming under Svalbard-

Assessing the 'general'consensus from the models -

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-192.png?6

they are general agreement that day 8/9 seem to be the day that shortwave energy starts undercutting through Northern scandi allowing the cold air to start to Filter West-

If we cast our mind back to last year it was this type of energy diving south that produced our bitter easterly- some call it a trigger low-

http://www.wetterzentrale.de/archive/ra/2009/Rrea00120090129.gif

THe low over towards warsaw was the one that swung all the way back to generate our cold air-

looking at the current evolution we will need X2 trigger lows to get the bitter air all the way to the UK- I think the reality is as with 99% of these situations is that the first trigger low will develop- the GFS & ECM both have it-

gfs parallel-

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-240.png?6 look at the 1010mb low-

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-252.png?6

This moves the cold air westwards into Central Europe over its Northern flank-

ECM is on the same page at day 10- ( 240 )

Which would probably be similar to GFS parallel at 252-

That is the first one - & im fairly sure Central europe at Day 10/11 -~ around Dec 14 will see its first bitter air of the year-

Look at the KIEV ensembles beginning to sniff this out-

http://www.wetterzentrale.de/pics/MT8_Kiew_ens.png

The all important development for the UK will come approx +1 / 2 days after that initial movement west - & needs to be another trigger low diving south as pressure rapidly rises to the west in the central atlantic- ( this is usually our stumbling block)

follow the parallel at 276

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-276.png?6 << this is exactly what we want to see for the atlantic profile ( the pressure rise can be further west, but not east-or worst still SE-

Can it happen- Well yes it can- There will be people that say all day long that it cant,however recent examples of this same jet profile have been rearing their heads-

Xmas 05, feb 05 ( 16 day easterly), last year- & a few more inbetween- the only drawback being is they have been at times when the Air mass was significantly warmer than whats potentially on tap this time around-

As a counter balance though its worth mentioning that the 2 or 3 times the PV has dropped into the oMoscow area & the first Ph1 trigger low has done its job the second trigger low & subsequent ridging has sent the bitter air away from us-

This was the last huge let down-

http://www.wetterzentrale.de/archive/ra/2007/Rrea00120070221.gif

So then to date- we havent had this >>

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-324.png?6 since End of 96/start 97- some 12 years ago-

The odds are stacked against us, but with tentative signs of a recovery over the last few years & this years positive overall indicators I would say the odds are slightly better than they have been in the last decade.......

If its gonna happen the window is there between day 11 & 15-

Steve

Edited December 4, 2009 by Steve Murr

[Dingwantssnow]

SO the difference from this year to other recent years is that everyhting IS in place for us to get a good cold spell?? We just need the trough to wander off westwards and for the euro high to party with the scandi high??

I know there probably alot more involved but im new to this and just trying to get my head round models etc etc.

Cheers

DWS

[Guest North Sea Snow Convection]

The thing is reef, a few people who are capable do try and predict what will happen after a reliable period based on good sound reasoning and experience and with the use of similar analogues. Their predictions and suggestions are reasonable based on the evidence put forward. They are looking a little bit further then the models and I would not say that any predictions they make is just their imagination or nonsense.

Why would GP bother otherwise?

Thanks for that - it encapsulates rather better, exactly what I was trying to say

[Osbourne One-Nil]

I was as suprised as anyone to learn he was only 13.

And a girl to boot.

[Frosty.]

I dont really take part in the model discussions any more- However things are a tad interesting at the moment-

Apart from the background teleconnection information>> the components of the overall jet strength & location -like the Temp of the stratosphere & negative wind anomaly the reality is we see a chunk of polar vortex energy dropping in towards Eastern Europe ~ around Moscow-

http://www.wetterzentrale.de/pics/MT8_Moskau_ens.png

( Of note was the 06z was an outlier in the mid term )

Most will have noted that over the last few days that the moscow ensembles from the GFS brought in the cold quite quickly, however it was moved back by a couple of days-

The point being here is that the model hadnt even resolved the location of the PV- so whatever we see or saw in FI was irrelevant as you would never be able to assess what the correct solution was - cold or warm-

Move through to today & we are firming up on the how the energy drops into that area & the subsequent flow that develops out of Eastern Europe coming under Svalbard-

Assessing the 'general'consensus from the models -

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-192.png?6

they are general agreement that day 8/9 seem to be the day that shortwave energy starts undercutting through Northern scandi allowing the cold air to start to Filter West-

If we cast our mind back to last year it was this type of energy diving south that produced our bitter easterly- some call it a trigger low-

http://www.wetterzentrale.de/archive/ra/2009/Rrea00120090129.gif

THe low over towards warsaw was the one that swung all the way back to generate our cold air-

looking at the current evolution we will need X2 trigger lows to get the bitter air all the way to the UK- I think the reality is as with 99% of these situations is that the first trigger low will develop- the GFS & ECM both have it-

gfs parallel-

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-240.png?6 look at the 1010mb low-

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-252.png?6

This moves the cold air westwards into Central Europe over its Northern flank-

ECM is on the same page at day 10- ( 240 )

Which would probably be similar to GFS parallel at 252-

That is the first one - & im fairly sure Central europe at Day 10/11 -~ around Dec 14 will see its first bitter air of the year-

Look at the KIEV ensembles beginning to sniff this out-

http://www.wetterzentrale.de/pics/MT8_Kiew_ens.png

The all important development for the UK will come approx +1 / 2 days after that initial movement west - & needs to be another trigger low diving south as pressure rapidly rises to the west in the central atlantic- ( this is usually our stumbling block)

follow the parallel at 276

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-276.png?6 << this is exactly what we want to see for the atlantic profile ( the pressure rise can be further west, but not east-or worst still SE-

Can it happen- Well yes it can- There will be people that say all day long that it cant,however recent examples of this same jet profile have been rearing their heads-

Xmas 05, feb 05 ( 16 day easterly), last year- & a few more inbetween- the only drawback being is they have been at times when the Air mass was significantly warmer than whats potentially on tap this time around-

As a counter balance though its worth mentioning that the 2 or 3 times the PV has dropped into the oMoscow area & the first Ph1 trigger low has done its job the second trigger low & subsequent ridging has sent the bitter air away from us-

This was the last huge let down-

http://www.wetterzentrale.de/archive/ra/2007/Rrea00120070221.gif

So then to date- we havent had this >>

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-324.png?6 since End of 96/start 97- some 12 years ago-

The odds are stacked against us, but with tentative signs of a recovery over the last few years & this years positive overall indicators I would say the odds are slightly better than they have been in the last decade.......

If its gonna happen the window is there between day 11 & 15-

Steve

Nice to see a post which is model related.

A great read there SM. I noticed the meto update is not enthusiastic about high pressure taking control, it only looks like a partial temporary victory with the unsettled weather taking control again in the days leading up to christmas, fingers crossed we see something wintry soon.

[Paul]

Just wanted to draw people's attention to this thread discussing the model threads on here and how we can enhance them:

[shuggee]

However, looking at everything today, I think the chances of an easterly are increasing, although it remains an outsider. Lots to watch over the coming days.

Is that a ramp Ian?! :(

[reef]

Is that a ramp Ian?! :lol:

As it contains a disclaimer aswell, perhaps it is a modern ramp.

[Methuselah]

As it contains a disclaimer aswell, perhaps it is a modern ramp.

:lol: :lol:

Sorry Ian. I do take the Modern Era quite seriously...But that was funny!