Model Output Discussion

[weather eater]

Agreed , the models have absolutly no idea whats goin on , the only thing thats consistant is the high to our north east really, as for them raging south westerlies with at one point a pool of 10c uppers is about as stupid as its ever goin to get , it annoys the hell out of me to see the forecasting models throwing in such extreme predictons each day , surely there is no point in the F1 as it hasnt even been any good for trends as of late , gives ppl somethin to talk about thats all it does .

FI is always good for trends, but I keep saying this, the trouble is there are several trends, which one is right. What happens is they get cherry picked, its a talking shop and better to ignore. At the moment what seems to be happening is that every time something good appears on the charts, the usual suspects, jump the gun, slate IB, we get comments like where's your even larger teapot now, I thought these synoptics couldn’t happen in the even larger teapot etc, failing to remember that they haven’t happened yet. Better to save the gloating until the evidence is overwhelming I would have thought.

So where are we now, temps close to average staying unsettled, if a pointer is needed to future events read GPs posts he's more on the money by a country mile than most on NW.

[bluearmy]

Another freebie ecm info today is all 50 ensemble members upto 168hrs, quite a few scenarios on show.

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2009120100!!/

Having looked through them all i'd say theres 8 members that could go on to develop something interesting by 240hrs, quite a few though take the trough too far north and east with ridging into southern europe. The problem i think for many is remaining patient to see if the pattern evolves over time but there would be an awful lot of rain and wind beforehand, IMO the quickest way out of this is the trough hangs back further west and disrupts with cut off low heading se'wards unfortunately this looks like a longshot.

if you have time nick, maybe you could reset the base for yesterday's 12z and see how supported the op was at T168??

the reality as is posted earlier is that events in the arctic look to be quite unprecedented in recent times at this early part of the season. the models will continue to struggle with which parts of the NH to jetison the cold over the next weeks. despite the apparent hunger to devlop a scandi high, GP cautioned against it, given background signals. many LRF,s called an average to mild decamber for NW europe with scandi cold. could well be right. if the blocking remains over the arctic for an extended period, we could well be in for a prozac filled month or so.

funily enough my wife asked me last night why i was spending so much time on the 'bloody computer'. i replied that there was much interest in the computer models and that there were signs of something noteworthy on the horizon. her answer was - 'you say that every year at this time'.

[Eugene]

I`m hoping the euro's are right by keeping us in cooler westerlies and not bringing unseasonable warmth next week like GFS 00Z, i hope the high to our NE actually moves northeast so to keep us away from horrendous warm southerlies only bottesford likes, at least with westerlies you get PM air in the mix.

[I remember Atlantic 252]

I`m hoping the euro's are right by keeping us in cooler westerlies and not bringing unseasonable warmth next week like GFS 00Z, i hope the high to our NE actually moves northeast so to keep us away from horrendous warm southerlies only bottesford likes, at least with westerlies you get PM air in the mix.

not sure I agree, westerlies PM will only be rain for us in W midlands, at least the 00Z looks dry with warm southerlies, dont fancy 7°C and rain,

[nick sussex]

So close to a cut off low here, this would be the quickest route to cold which would avoid lots of wind and rain, we stll need the main trough further west though.

[Iceberg]

The operationals were probably too progressive last night but today's output is none-the-less very interesting.

GFS mean H5 anomaly for days 11-15 and the operational ECM and GFS are suggesting a noteworthy longwave pattern developing across the NH:

http://raleighwx.easternuswx.com/models/gfsensemble/00zENS11-15day500mbHeightAnomalyNH.gif

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/hgtcomp.html

These show three discrete major upper level vortices developing across the mid latitudes. We've not seen that for a long time.

In the medium to long term, it continues to look unsettled and close to average but with the interesting stuff building far to our north-east.

GP thoe models have certainty been toying with such a pattern with anything upto 5 descrete vortex's giving a very amplified pattern.

The potential cross polar flow with the dual HP's over Alaska and cuckey sea looks to have been the favourite though, the problem is that it's too far east giving us the warm southerlies or even further NE giving us the wet SW winds.

A chance in the second half of December that the pattern will change allowing some retrogression, but whether it's enough to give us either a very mild christmas or a cold one is still in the air atm.

Those wishing for the candy now should wait, lets keep the HP cells where they are progged to allow the cold pool to develop.

[nick sussex]

if you have time nick, maybe you could reset the base for yesterday's 12z and see how supported the op was at T168??

the reality as is posted earlier is that events in the arctic look to be quite unprecedented in recent times at this early part of the season. the models will continue to struggle with which parts of the NH to jetison the cold over the next weeks. despite the apparent hunger to devlop a scandi high, GP cautioned against it, given background signals. many LRF,s called an average to mild decamber for NW europe with scandi cold. could well be right. if the blocking remains over the arctic for an extended period, we could well be in for a prozac filled month or so.

funily enough my wife asked me last night why i was spending so much time on the 'bloody computer'. i replied that there was much interest in the computer models and that there were signs of something noteworthy on the horizon. her answer was - 'you say that every year at this time'.

Its very difficult to tell as the pattern only gets interesting later on yesterdays ecm 12hrs run, looking at things today there are IMO three ways this could play out, we have a large low pressure stuck to the west or sw battling against the high to the east and ne, this will spawn secondary features which will run east and and then ne then head back nw becoming absorbed into the main low eventually you hope in line with GP's post that eventually high pressure nudges sw and sinks the trough bringing in colder easterlies this however could take a long time and in the meantime huge amounts of rain, the next was my longshot where the trough hangs back further west throwing out shortwaves, one of these runs east into france allowing pressure to ridge westwards over the top, this IMO would be the quickest route to cold, finally the worse case scenario the trough makes too much eastwards and ne'wards progress dropping heights to the ne, russian high pressure throws a ridge sw under the trough and you get an increase in pressure over southern europe and a much milder pattern takes over, this would take a while to get out of.

In terms of trends a good one would be to see the trough edged west and further south in the models, also look out for how many ensembles do this, its dificult to say how this will turn out, the problem i have with cold projections that take a lot of time to occur is simply the longer the timeframe the more likely another variable will be thrown into the mix to scupper this.

Edited December 1, 2009 by nick sussex

[cooling climate]

Apart from tomorrow temperatures look very suppressed on the 06z GFS run.

As the models get to grips with a -AO pattern developing over the Arctic I still think a

much colder pattern developing in the 8 to 10 day range is a distinct possibility.

[Guest North Sea Snow Convection]

Its very difficult to tell as the pattern only gets interesting later on yesterdays ecm 12hrs run, looking at things today there are IMO three ways this could play out, we have a large low pressure stuck to the west or sw battling against the high to the east and ne, this will spawn secondary features which will run east and and then ne then head back nw becoming absorbed into the main low eventually you hope in line with GP's post that eventually high pressure nudges sw and sinks the trough bringing in colder easterlies this however could take a long time and in the meantime huge amounts of rain, the next was my longshot where the trough hangs back further west throwing out shortwaves, one of these runs east into france allowing pressure to ridge westwards over the top, this IMO would be the quickest route to cold, finally the worse case scenario the trough makes too much eastwards and ne'wards progress dropping heights to the ne, russian high pressure throws a ridge sw under the trough and you get an increase in pressure over southern europe and a much milder pattern takes over, this would take a while to get out of.

In terms of trends a good one would be to see the trough edged west and further south in the models, also look out for how many ensembles do this, its dificult to say how this will turn out, the problem i have with cold projections that take a lot of time to occur is simply the longer the timeframe the more likely another variable will be thrown into the mix to scupper this.

Hi nick

The first scenario alas keeps looking the most likely. What is needed is a drop in zonal winds to allow a retrogression of the pattern, as you suggest thereby edging this bugbear trough back westwards or southwestwards and/or an undercut of the lows. Although it seems from reading the excitement on here last night the computer models were hinting at an undercut it is unlikely to happen atm.

I think we wait for a proper warming event of the stratosphere and drop in zonal winds before the atlantic gets a life and leaves us alone. The best that can be said is pretty much as Iceberg alluded to in that areas we want to be cold to tap into later *should* have a supply of cold air available. But a muddy and uninteresting December awaits first perhaps before the pattern might finally yield the tinsel land further outlook that the computer models will no doubt keep suggesting *she says hoping to be very wrong!*

Apart from tomorrow temperatures look very suppressed on the 06z GFS run.

As the models get to grips with a -AO pattern developing over the Arctic I still think a

much colder pattern developing in the 8 to 10 day range is a distinct possibility.

Be nice if you were right! But as Dec 1978 showed, it took till the last week of the month before the dam(n) finally broke. So even our coldest winters don't usually yield these synoptics this early

Edited December 1, 2009 by North Sea Snow Convection

[karyo]

I think we wait for a proper warming event of the stratosphere and drop in zonal winds before the atlantic gets a life and leaves us alone. The best that can be said is pretty much as Iceberg alluded to in that areas we want to be cold to tap into later *should* have a supply of cold air available. But a muddy and uninteresting December awaits first perhaps before the pattern might finally yield the tinsel land further outlook that the computer models will no doubt keep suggesting *she says hoping to be very wrong!*

Unfortuntely, you will probably be right Tamara! If we had a significant stratospheric warming I would also be more positive but at the moment this is not happening. If anything a cooling looks more likely in todays outlook!

Karyo

[Methuselah]

Be nice if you were right! But as Dec 1978 showed, it took till the last week of the month before the dam(n) finally broke. So even our coldest winters don't usually yield these synoptics this early

That's true, Tamara. Even the famed '80s winters (December 1981 excepted) didn't provide much until around New Year, or thereafter...

[Guest North Sea Snow Convection]

Unfortuntely, you will probably be right Tamara! If we had a significant stratospheric warming I would also be more positive but at the moment this is not happening. If anything a cooling looks more likely in todays outlook!

Karyo

Hi Karyo - I think that we will continue to see disruption of the polar vortex with more mountain torque induced minor warmings. Most of the experts don't appear to support a cold stratosphere this year - in fact as has been documented, thus far it has been anything but. So although we have a headache of an eastern atlantic/Uk trough to deal with, the usual organised Greenland vortex looks much less likely to be a dominant force than usual.

Barring a sudden unexpected and more prolonged cool off in the stratosphere then in theory, at least, the present scenario problem *should* be easier to overcome when the background factors and telecommunications become more favourable. Better to be starting from a weakened vortex than a strong one - that is why we need to see more wave breaking upticks on that berlin site graph to ensure that this remains the case

[memories of 63]

I'm surprised no one has mentioned the GEFS Operational Control from the 00z or today's 06z. Both show the start of the next ice age from mid month onwards. If anything today's 06z is 'colder' than the 00z

Edited December 1, 2009 by memories of 63

[kold weather]

Looking more probable that we are going to get a more southerly influence as the lows just seem a little too strong at the moment, which is a shame as we are going to waste what appears to be some pretty strong northern blocking developing. Still as Peter said many 80s winters had warmer December's probably due to a similar issue with whats going on now.

If we do get a cold pattern its going to be locked in for some time I'd have thought, but for now the stubborn UK upper trough isn't going nowhere.

[weathernewbie]

I'm surprised no one has mentioned the GEFS Operational Control from the 00z or today's 06z. Both show the start of the next ice age from mid month onwards. If anything today's 06z is 'colder' than the 00z

Yes, starting to look tasty, way out there in the distant future. If only.

Tasty FI

[grab my graupel]

Hi Karyo - I think that we will continue to see disruption of the polar vortex with more mountain torque induced minor warmings. Most of the experts don't appear to support a cold stratosphere this year - in fact as has been documented, thus far it has been anything but. So although we have a headache of an eastern atlantic/Uk trough to deal with, the usual organised Greenland vortex looks much less likely to be a dominant force than usual.

Barring a sudden unexpected and more prolonged cool off in the stratosphere then in theory, at least, the present scenario problem *should* be easier to overcome when the background factors and telecommunications become more favourable. Better to be starting from a weakened vortex than a strong one - that is why we need to see more wave breaking upticks on that berlin site graph to ensure that this remains the case

Hi Tamara

If the experts are correct, re the stratosphere, then that is a very encouraging sign indeed.

Not having the PV set up shop over Greenland is an essential part of the Jigsaw puzzle.

The finer details don't matter too much at this stage.

[MR EXTREMES]

One thing that can be said though is that we will get the cold pooling to our East and North that we were all desperate for a few weeks ago

yes been keeping an eye on this and some real cold getting there good news for them.

but so far east scandi would be better,

but i was on the money lastnight with my april the 1st prediction lol in other word models were throwing a april fools joke lastnight lol.

Edited December 1, 2009 by badboy657

[bluearmy]

I'm surprised no one has mentioned the GEFS Operational Control from the 00z or today's 06z. Both show the start of the next ice age from mid month onwards. If anything today's 06z is 'colder' than the 00z

assuing that you mean the control run, i guess it depends where it is at T180 where it becomes a higher resolution than the op. if it hasnt picked up the shortwave development and disruption between T96 and T180, its unlikely to be right beyond T180. good that its cold but just a variation on the general theme.

the NAEFS in the latter stages of its run have blocking around svaalbard and west to eastern canada. all very promising although the ah is ridging across to southern europe which prevents the trough driving south east and infact its as a bit further north than it was on yestedays 12z in mid atlantic. hopefully we will see the blocking to our north drift a bit further south as the time approaches to help push the whole pattern south.

[Methuselah]

yes been keeping an eye on this and some real cold getting there good news for them.

but so far east scandi would be better,

but i was on the money lastnight with my april the 1st prediction lol in other word models were throwing a april fools joke lastnight lol.

I see where you're coming from, BB...BUT, wouldn't a massive, solid 'immovable' source of potential wintryness be better than a (more transient?) Scandi High - in the longterm??

[Guest North Sea Snow Convection]

Hi Tamara

If the experts are correct, re the stratosphere, then that is a very encouraging sign indeed.

Not having the PV set up shop over Greenland is an essential part of the Jigsaw puzzle.

The finer details don't matter too much at this stage.

Hello Brian - nice to see you posting again

Yes indeed - and one can hope that the models start to downgrade the projected strength of the low pressure areas with time

[kold weather]

Only if the Atlantic stops throwing 960-950mbs into the middle of the Atlantic at the same time Peter and just holding them there, otherwise that source of possible wintryness will just lock us into a pattern that eventually would turn mild, and wet as well. With a cutting low though things would get interesting but I think it seems more probable that we are going to need another bite of the cheery down the line,

[Methuselah]

Only if the Atlantic stops throwing 960-950mbs into the middle of the Atlantic at the same time Peter and just holding them there, otherwise that source of possible wintryness will just lock us into a pattern that eventually would turn mild, and wet as well. With a cutting low though things would get interesting but I think it seems more probable that we are going to need another bite of the cheery down the line,

Very true...

[Thundery wintry showers]

Yes, in the short to mid term this milder scenario is what I am expecting. I think the next wave of energy coming into the jet will keep the blocking highs stuck away to the N and E while Britain ends up in a mild moist southerly flow. That said, the upcoming week looks like being merely average in terms of temperature- the mild southerly type will probably take a while to set in.

For those wanting a mild dry sunny southerly flow remember also that dry doesn't necessarily mean sunny- January 1996 for example had a lot of dry weather from southerly winds but it was widely the dullest on record. A relief from the inceasant rain in western districts would certainly be welcome from a flooding perspective but I don't think a southerly pattern would achieve that- it would most likely be dry in the east but wet in the west (the same western areas that desperately need a bit less rain!).

[Duane S.]

Only if the Atlantic stops throwing 960-950mbs into the middle of the Atlantic at the same time Peter and just holding them there, otherwise that source of possible wintryness will just lock us into a pattern that eventually would turn mild, and wet as well. With a cutting low though things would get interesting but I think it seems more probable that we are going to need another bite of the cheery down the line,

I think that is a very realistic view of what is possibly the most likely outcome.

[snowmadchrisuk]

I think that is a very realistic view of what is possibly the most likely outcome.

Latest MJO chart Just come out and we seem to be heading slowly towards phase 7 again .