Model Output Discussion

[John Cox]

Just dont see whats downbeat about this.

[Altostratus]

Horrible 6Z - it would be very frustrating if that verifies. The jet loop running between Iceland and Norway never dies down and this prevents pressure from building into the key area. With the whole pattern stopped in its tracks, only eastern (possibly south eastern) parts of Europe would benefit from any CAA along the underside of the block. Without pressure building up into GL, the GFS scenario for energy reinvigorating over the block is quite likely. As I said last night, the really interesting developments are still in FI so plenty of time for change. Several days yet before the correct evolution is known I would have thought. The potential is still there, but patience may be needed.

[TEITS]

This thread has come back down to Earth now, just goes to show, models change all the time, and looking into FI all the time and believing it, well it's suicide.

GFS and UKMO picked up on a different pattern, all it takes is the ECM to agree on the 12z, and then it's pretty much dead in the water. 06Z now shows a North Easterly even further out in FI..

I have to say i've read a few posts suggesting we were believing the E,ly. If you go back and read the posts we were discussing what the models are showing. However many of us including myself have said we need to get this pattern within +72.

As for saying "it's pretty much dead in the water" aren't you doing exactly the same thing by believing F.I!!

Very little has changed in my eyes because the uncertainity continues. However using the 7th Feb as an example there isn't one single 0Z GEFS member that agrees with the LP around Iceland at +216 on the 06Z run.

Lets not make the mistake of believing the poor runs and disbelieving the excellent runs. This happens due to members experienes in the past. However so far this winter it hasn't been your typical winter!

[BLAST FROM THE PAST]

This thread has come back down to Earth now, just goes to show, models change all the time, and looking into FI all the time and believing it, well it's suicide.

GFS and UKMO picked up on a different pattern, all it takes is the ECM to agree on the 12z, and then it's pretty much dead in the water. 06Z now shows a North Easterly even further out in FI..

That is doing precisiely what you are preaching against. So the UKMO is to be exactly right at t144? That is FI so you shouldn't be looking there? Dead in the water...FI is set then yes?

Aha, precisely Dave, you beat me to it!

BFTP

Edited January 29, 2010 by BLAST FROM THE PAST

[The Weather Dragon]

So.....a few days into this saga and signs of any easterly remain in FI territory, probability if anything has reduced. Like I said in a previous post I will dismiss all thoughts of an easterly until I see cross model agreement at 144 hours.

[chionomaniac]

There is a fine margin of error at t120 to t144 in terms of the amount of energy that comes off the trough to the west in the atlantic and the connective ridge to the south joining up with the block to the north east.

I would expect that UKMO shows the absolute worst that could happen and has probably overdone the energy eastwards, however it is a warning that this isn't resolved yet by any means and therefore any glitzy output in FI on other modelling is only just that atm. My own humble experience shows actually that the UKMO is these situations has been the one to call the party off, and often has been right. In this situation, taking into account the background factors that might be less likely - however it is a clear demonstration that a wait and see policy carries on.

There is still a good chance that we might see high pressure close to the UK with a modest continental flow but the coldest air remaining to the east, much as GEM seems to suggest. Yes, the ensembles atm are still good - but to me that doesn't mean much at this range because there is still a long time available for that to change.

It could well all come together but more work to be done imo.

Edit: I agree with the thoughts on the stratosphere thread and the uncertainties there. That underpins the cautionary note.

The difference between today and yesterday is down to how the Scandi trough fills and Atlantic trough grows. Yesterday the 100Hpa profiles suggested that these two events would be separated but today the evolution is more of one slow retrogression which prevents that AH ridging over the UK and bolstering the easterly. However with the amount of negative mean zonal wind propagation forecast we are likely to see further retrogression of the atlantic trough, with the Arctic ridge dropping more to our NW than NE now. But from the direction it moves that could bring in some very cold air from the NE. So as GP suggests long term things still looking good for a deep cold spell.

[Cecil Hogmanay Melchett]

The difference between today and yesterday is down to how the Scandi trough fills and Atlantic trough grows. Yesterday the 100Hpa profiles suggested that these two events would be separated but today the evolution is more of one slow retrogression which prevents that AH ridging over the UK and bolstering the easterly. However with the amount of negative mean zonal wind propagation forecast we are likely to see further retrogression of the atlantic trough, with the Arctic ridge dropping more to our NW than NE now. But from the direction it moves that could bring in some very cold air from the NE. So as GP suggests long term things still looking good for a deep cold spell.

is he?

I thought a west based -NAO was not great for the UK?

[Lewis]

That is doing precisiely what you are preaching against. So the UKMO is to be exactly right at t144? That is FI so you shouldn't be looking there? Dead in the water...FI is set then yes?

Aha, precisely Dave, you beat me to it!

BFTP

Exactly, proves my point. You cannot loose with FI

Stick to short term...

[BLAST FROM THE PAST]

The difference between today and yesterday is down to how the Scandi trough fills and Atlantic trough grows. Yesterday the 100Hpa profiles suggested that these two events would be separated but today the evolution is more of one slow retrogression which prevents that AH ridging over the UK and bolstering the easterly. However with the amount of negative mean zonal wind propagation forecast we are likely to see further retrogression of the atlantic trough, with the Arctic ridge dropping more to our NW than NE now. But from the direction it moves that could bring in some very cold air from the NE. So as GP suggests long term things still looking good for a deep cold spell.

Yes C

That is the synoptic development as I have been seeing it for some time. Pressure to build to our NW and not NE, it looked dodgy model wise BUT we see the seeds being sewn now with ECM IMO showing the way.

SFL, then maybe you should drop the dead in water bit?

BFTP

Edited January 29, 2010 by BLAST FROM THE PAST

[chionomaniac]

is he?

I thought a west based -NAO was not great for the UK?

I think that the 11-15 day GEM/ GFS anomaly charts that GP linked to showed that type of cold set up but with the greatest core of heights more towards Canada.

[The Weather Dragon]

Just dont see whats downbeat about this.

This chart is superb ..... Problem is that it's way out in FI & more than likely won't verify.

Edited January 29, 2010 by Jonathan Evans

[TEITS]

But from the direction it moves that could bring in some very cold air from the NE. So as GP suggests long term things still looking good for a deep cold spell.

Excellent post CH.

I agree with GP that eventually we will see a W based NAO. However to get into that position could mean spell of very cold NE,lys. What members need to realise is even if we don't see a prolonged spell of E,lys the chance of a spell of NE,lys remains possible. The only difference is the very cold NE,ly spell wouldn't be as prolonged as an E,ly cold spell.

Im still happy with the GEFS mean.

http://91.121.94.83/modeles/gens/run/gens-21-1-180.png?6

Seems beyond we pick up a very cold ESE,ly.

[Methuselah]

But, a very cold NErly would deliver more in the way of snow...As always, the far-reaches of FI (not Formula One!) look okay!

[weather eater]

Lets not make the mistake of believing the poor runs and disbelieving the excellent runs. This happens due to members experienes in the past. However so far this winter it hasn't been your typical winter!

No Dave it hasn’t, but the models reading of it and the range at which they can be relied upon has not changed.

If we just sit back and ignore the details in regards how the Easterly sets up, the constant pattern matching with winters past, which I have to say you are rather prone to do, then the board trend to northerly blocking in the longer term output, winds N/NE/E remains pretty consistent, frankly as good as I can remember it.

Further more, I think its wise to remember that just because 47 style synoptics don't show their hand every run that’s not a reason to throw in the towel. It rather seems at the moment that no matter what changes occur in the early evolution, we still manage to get there in the end. I would say that in itself, that’s a pretty unusual thing to see, particularly over so many runs on different models.

[Bobby]

I wouldn't get too upset about UKMO +144, it would very likely show something better if it went further out as the block pushes in. There is nothing at all to suggest a mild wet atlantic dominated period.

Models are very confused and messy at the moment, perhaps we may have to wait a bit for the easterly but the signals are strong, ensembles good and lots of superb charts consistently showin out in FI by the models. So we may have to be patient but it does look like something tasty will be coming in February.

[TEITS]

Exactly, proves my point. You cannot loose with FI

Stick to short term...

Im not picking on you Lewis as what im about to say is to all members.

I feel some are suffering from short term memory loss. I distinctly remember some negative posts back in early Dec and after xmas wrt believing the poor runs and disbelieving the excellent runs. However as we very well know the excellent model runs proved to be correct.

All im trying to say is do not allow previous winter disappointments to affect your judgement. The outlook is very uncertain but at the moment a cold E,ly is just as likely as surface cold via HP over the UK. Look at all the data rather than just the operationals.

[Bobby]

People say "the easterly is only showing in FI"... but it's been consistently showing in FI now for several days - on the GFS and ensembles, ECM and ensembles, some of the smaller models etc. When you see this consistency even in FI it's highly unlikely it'll all flip.

Have to look at the big picture instead of individual charts on individual runs.

Also, the GFS op is a big mild outlier in the mid term.

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=197&y=128

[TEITS]

It rather seems at the moment that no matter what changes occur in the early evolution, we still manage to get there in the end. I would say that in itself, that’s a pretty unusual thing to see, particularly over so many runs on different models.

Very good point and this is what I have noticed too.

Excellent ensembles yet again.

http://charts.netweather.tv/ensimages/ens.20100129/06/t850Cambridgeshire.png

Looks like the 06Z GFS didn't have much support from the SLP Iceland ensembles.

http://charts.netweather.tv/ensimages/ens.20100129/06/prmslReyjavic.png

This doesn't make the Op wrong though. Im just going to sit on the fence with this one and hope the words "Easterly" and "snow showers in the E" appear on the latest Met O forecast.

[The Weather Dragon]

People say "the easterly is only showing in FI"... but it's been consistently showing in FI now for several days - on the GFS and ensembles, ECM and ensembles, some of the smaller models etc. When you see this consistency even in FI it's highly unlikely it'll all flip.

Have to look at the big picture instead of individual charts on individual runs.

Also, the GFS op is a big mild outlier in the mid term.

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=197&y=128

It could quite easily flip - as it has done before with shorter timeframes

[Southender]

Looking at the GFS Ens from this morning (With my Data Analyst hat on - which is what I do for a living) There is something seriously wrong with the OP run around 5th Feb. Either missing data or corrupt data, as shown by the big decline then subsequent sharp rise in such a short timeframe. This then goes on to effect the outcome in the mid term, as you would expect if something is not right earlier on in the run.

You can clearly see its a massive mildy outlier in the mid term and in my opinion bin it.

Edited January 29, 2010 by LeighShrimper

[D KARLSON]

Talk about greed ,were like kids in a candy shop weve got synoptics now providing for some areas and were still looking ahead for bigger and better,that said that low that comes from the northwest on tuesday could well provide some heavy falls of snow as it hit s the cold air on the eastern side.

as for tonights models ,i think perhaps the models might converge a little and come to a more of a conclusion as regards any cold outbreak from the east ,i think the UKMO will backtrack and come in line more with the GEM but thats just a good guess ,but ceretainly expect changes in tonights models as is the case in these situations there can be quite sudden turn arounds as the cold and mild does battle

[SP1986]

As has been said the easterly still has every chance of occurring, but when ensembles were posted the other day on here I noticed a handful of runs going for a southwesterly and recognised that this easterly certainly isn't steadfast. The ECM still looks promising for the easterly however the GFS and UKMO operations have backed away a little in the reliable timeframe. Although the GFS ensembles are showing majority cold there are a string of ensembles having moved to somewhat milder conditions - that said I recall when I was checking out milder ensembles in a similar scenario last year being told the operational counts more than the rest of the ensembles due to it's higher degre of accuracy, if that's true that may represent a challenge to the easterly.

I still think getting a moderately negative NAO is key here over all else.

Without doubt the easterlies will come back into the more reliable timeframe on GFS, UKMO over the coming days but it's whether the final product measures up to the expectation that has been pumped into the forum atmosphere transpires that remains to be seen.

Looking at the GFS Ens from this morning (With my Data Analyst hat on - which is what I do for a living) There is something seriously wrong with the OP run around 5th Feb. Either missing data or corrupt data, as shown by the big decline then subsequent sharp rise in such a short timeframe. This then goes on to effect the outcome in the mid term, as you would expect if something is not right earlier on in the run.

You can clearly see its a massive mildy outlier in the mid term and in my opinion bin it.

I'm sure Paul will be able to assure you that's not the case - I've said this myself before thinking it might be the case before when the GFS was recording extremely low temperature data, but alas it wasn't the case and the data was viable. I can't myself see anything wrong with it to be fair.

[John Cox]

The 2m min temps ensembles for Dublin look great to me and the operational run is bang in the middle and with the scatter quite close, even in the FI range.

I think things look really good and don't think members need to be despondent.

[Glacier Point]

So as GP suggests long term things still looking good for a deep cold spell.

Not sure how long it would last though Ed.

Using the mid-December pattern as a blueprint, that went on for some 10 - 12 days in the south, longer in the north. It threatend to be a west based -NAO but height rises back towards Iceland helped sustain the pattern.

Synoptically, west based -NAO are more likely in February during Ninos and the wavelengths may not necessarily favour the same evolution or extent of the December event. The challange in front of us though are how will further warmings in the stratosphere manifest themselves ? I suspect that we will feature a substantive blocking structure over the Canadian Arctic throughout Febraury into March.

[Spurry]

Not sure whether this represents a trend or not ,but it appears that the Easterly only breaks thru in the lo res run, this seems to have shown on the last 2-3 runs...if i were a betting man my money would be on a stalemate over the British Isles with us being in that 'no mans land' again regards Cold/Mild air, before the atantic finally breaks through.