Jump to content
Sign in to follow this  
Paul

Model output discussion - 5th December 2016 - Into Winter we go

Recommended Posts

2 minutes ago, Paul_1978 said:

Must be just me then - I thought this afternoons runs were pretty good! We've had a lot lot worse!

The runs are in the main dry and cold but after the meto update and the afternoon runs moving away from any true high lat blocks i can see where steve is coming from...

Share this post


Link to post
Share on other sites
14 minutes ago, northwestsnow said:

The runs are in the main dry and cold but after the meto update and the afternoon runs moving away from any true high lat blocks i can see where steve is coming from...

The teleconnections have never supported a high lat block though(MJO/AAM). The models should never be taken at face value when they show HLB.

Edited by mountain shadow

Share this post


Link to post
Share on other sites
1 minute ago, mountain shadow said:

The teleconnections have never supported a high lat block though(MJO/AAM). The models should never be taken at face value when they show HLB.

And neither should the teleconnections, were they not indicating HLB and colder conditions through December ? Neither should be taken at face value 

Share this post


Link to post
Share on other sites
7 minutes ago, shotski said:

And neither should the teleconnections, were they not indicating HLB and colder conditions through December ? Neither should be taken at face value 

No they werent. There were predictions about the teleconnections that might lead to HLB but they didnt occur.

The teleconnections right now do not support HLB favourable for a snowy spell here.

Share this post


Link to post
Share on other sites

Gfs puts us in the freezer snow showers blizzards easterly gales channel lows I do think January is going to be lot colder then December winter is sneaking up on us .. :D 

IMG_0098.GIF

IMG_0099.PNG

Share this post


Link to post
Share on other sites
23 minutes ago, mountain shadow said:

No they werent. There were predictions about the teleconnections that might lead to HLB but they didnt occur.

The teleconnections right now do not support HLB favourable for a snowy spell here.

No probs, my knowledge of such things  are far lower than most on here. I just assumed , obviously wrongly, that the Met office would use teleconnections and back ground signals in their forecasts.:cc_confused:

Edited by shotski
Spelling

Share this post


Link to post
Share on other sites
36 minutes ago, Dennis said:

 

Indeed. That's what you call a downward trend. 

image.gif

Share this post


Link to post
Share on other sites

Well the Northerly that was shown in the output over the last few days around New Year looks to of gone the way of the pear. (snow-wise)

h850t850eu.png

Tis looking like just a very small Northerly toppler which will keep things on the chilly side to start 2017.

After it seems the high may settle back over us again keeping things chilly, its after we are looking at a potential for re-amplification as high pressure comes off the eastern seaboard.

h850t850eu.png

Whether we can get this is another story, GFS and along with the ECM show promise in their latter timeframes however once again this is in FI which could potentially go BAPS up, fingers crossed we will eventually hit the jackpot.

 

Share this post


Link to post
Share on other sites

It looks like this season is another one of constant teasers at day 10 that never get to day 9. Sometimes you just have to say it how it is. The ecm upgrade has obviously not ridden itself of the amplification bias to our north west. 

Share this post


Link to post
Share on other sites
2 minutes ago, vizzy2004 said:

Well the Northerly that was shown in the output over the last few days around New Year looks to of gone the way of the pear. (snow-wise)

h850t850eu.png

Whether we can get this is another story, GFS and along with the ECM show promise in their latter timeframes however once again this is in FI which could potentially go BAPS up, fingers crossed we will eventually hit the jackpot.

 

This chart would be nice and cold but the ECM is not as promising for surface cold as it lets the jet ride above the high so probably just a cloudy high.

Share this post


Link to post
Share on other sites
Just now, Hammer50 said:

Could this be a start to a 1963 scenario here's hoping.

 

No, that cold spell was well signposted, there was a weak Stratospheric vortex, the GLOSEA1 and the EC24 had strong support for it well in advance and the ECMWF and GEFS modelled it all the way in from 300 hours, it counted down like clockwork and subsequent modelling was very precise throughout that winter.

:D

Share this post


Link to post
Share on other sites
4 minutes ago, Hammer50 said:

Could this be a start to a 1963 scenario here's hoping.

 

Not a chance im afraid. 

Share this post


Link to post
Share on other sites

GFS op looks to have been on the 'milder' side up to the 7th and it certainly ain't mild. So perhaps one can insinuate the majority end up with HP centred more north/west - opening the gates more to cold air from E. Interesting how the mean takes takes a downwards path right in FI, Cohen's tweet suggest things could get exciting fertile ground for height rises to NW?

image.pngI

 

Edited by Changing Skies

Share this post


Link to post
Share on other sites

The anomalies this evening still in very good agreement upstream. All agree on the Canadian vortex and the dumbbells ( twin vortex ) Siberia and Russia with the Aleutian HP ridging between. There is also a trough running south down western N. America, It's downstream where there is a slightly different interpretation and it involves the orientation and position of the high pressure. NOAA and the GEFS have lying rather flat to the west of the UK with an upper flow WNW whilst the ecm has it ridging north more thus veering the upper flow north westerly. Could make some difference to the surface evolution the ecm interpretation more inclined to systems swinging south east and transient northerlies and some wintry fayre.(Still no anomalies for the ecm, Don't know whether it's me or the site)

610day.03.gifgefs_z500a_5d_nh_41.pngecm_eps_z500a_5d_nh_11.png

Going forward there are major differences. I can't post the EPS but it's not a million miles from NOAA  The GEFS on the other hand has severely weakened the dumbbells and it also has a fairly nondescript zonal flow across the Atlantic band even a suspicion of positive anomalies to the north east. At the moment I'm inclined towards NOAA and the EPS but really best to keep a watching brief

814day.03.gifgefs_z500a_5d_nh_61.png

 

Edited by knocker

Share this post


Link to post
Share on other sites

What an amazing day it's been for wildly diverse opinions that have each come from the same model runs...I guess it must be the booze talking? The Glenlivet interpretation vs the Laphroaig vs the Tesco Value vs the Macallan 1963?:cold:

Merry Christmas everyone. Hic!:drunk-emoji:

Share this post


Link to post
Share on other sites
5 hours ago, feb1991blizzard said:

No, that cold spell was well signposted, there was a weak Stratospheric vortex, the GLOSEA1 and the EC24 had strong support for it well in advance and the ECMWF and GEFS modelled it all the way in from 300 hours, it counted down like clockwork and subsequent modelling was very precise throughout that winter.

:D

Also more amazing, No super computers, limited technology but accurate

Share this post


Link to post
Share on other sites
4 minutes ago, Glacier Point said:

Well, with the GWO in likely low amplitude phase 2, we do have some agreement on what the extended gefs / eps are leaning right now [positive height anomalies to NW and below average temp signal].

The neutralisation that took place in angular momentum during December places us now exposed to short term spikes in tendency in relative angular momentum [amplification across the North Pacific ridge]. We also have the scope to begin to assume what ever was swamping the long lead signals in December has / is beginning to relent. 

Those longer lead trends did suggest building ridge tendency to our NE in time, so the longer term game for first three weeks of January will be significantly influenced by what ever cold poling develops over western Russia.

I've gone on record earlier this season suggesting there would be a disconnect between upper stratospheric conditions and lower strat / trop conditions. Right now with a strong upper pv, and the model output in front of us......

Right now there looks a fairly strong vortex at trop and strat levels, so surely it will need some strong tropospheric ridging (like the 2 wave pattern advertised on yesterdays output from pacific / Atlantic), realistically can that pattern persist long enough to produce a protracted spell of Northern blocking while the mid and upper strat vortex remains strong, in other words is a significantly wintry and cold Jan / feb or both feasible / likely?

Share this post


Link to post
Share on other sites
10 minutes ago, Tonyinhampshire said:

Also more amazing, No super computers, limited technology but accurate

Forgive if I've the wrong end of the stick - I haven't touched a drop today! - but, the winter of '63 was full of 'at least it'll be mild's being tacked on to the end of forecasts? It was just that, in that one particular case, the cold persisted for around two-and-half months! 

But, I do wonder how today's numerical models would have handled things...:D:cold:

Share this post


Link to post
Share on other sites
21 minutes ago, fergieweather said:

Yes they absolutely do. However, global teleconnections influential for the UK remain extremely weak for the forseeable and thus of little forecast use.

The only consistent element in latest longer-term forecasts is the unusually strong SPV signalled to remain throughout January, which - taken in isolation - would imply a leaning to +ve NAO. However, longer-range predictions aren't so clear-cut on NAO and the sudden lack of almost any useful signal in ECMWF beyond 1st week of January is, in itself, considered very unusual.

If basing prediction on GloSea5 alone, the anticyclonic theme remains dominant - but weakening - further into extended range (ie by d15), with this sinking south to allow a mean westerly flow across us and a gradual upward turn in temperature. However, given that a conspicuously colder phase looks set for first few days of 2017 (scope/longevity/severity uncertain) and signals then suddenly vanish thereafter, forecast confidence beyond week 1 of Jan remains much lower than normal.

Thank you Fergie weather, so looking at current data and models I would say the first 3 to 4 days of January look cold ,but beyond that ,signal for a return to westerly winds ,well gang that covers the next TEN days ,which we all know is ages in forecasting terms ,so let's hang on in there and prey ,great forum ,I would say probably the best in the world of weather forums , don't forget that on the score of Lost data over christmas any high at 10 days would be modeled far too south , (don't take my word for it ) right again my Christmas wishes to you all ,cheers gang  from a very mild West mendip village ,6 years ago minus 9 and 20 cms of the white stuff ,cheers :yahoo::cold:

Share this post


Link to post
Share on other sites
4 minutes ago, feb1991blizzard said:

Right now there looks a fairly strong vortex at trop and strat levels, so surely it will need some strong tropospheric ridging (like the 2 wave pattern advertised on yesterdays output from pacific / Atlantic), realistically can that pattern persist long enough to produce a protracted spell of Northern blocking while the mid and upper strat vortex remains strong, in other words is a significantly wintry and cold Jan / feb or both feasible / likely?

With 'a really strong trop vortex' in place and what seems to be a strong upper strat vortex (though again this seems to displace fairly easily towards Siberia with the onset of trop induced wave 1), how do you explain the modelling being chucked out at present which shows significant trop amplification??

a strong upper strat vortex/trop vortex combo surely wouldn't allow such patterns to develop ?? Remember the models are one trop/strat picture. They aren't separate entities. 

The gefs are  bouncing around a bit, the eps a bit more consistent. The Canadian ens now lost the euro low anomolies in the latter part of week 2, whilst the gefs/eps retain them. 

Share this post


Link to post
Share on other sites
57 minutes ago, Glacier Point said:

 

I've gone on record earlier this season suggesting there would be a disconnect between upper stratospheric conditions and lower strat / trop conditions. Right now with a strong upper pv, and the model output in front of us......

But in all seriousness - the reality has been the total opposite..

The trop conditions have almost mirrored to perfection the strength of the 10HPA vortex- 

Using the Merra data @ 10HPA V the AO which is the best barometer for any disconnect between the 2 shows a pretty cohesive upward response from the AO as the vortex recovered- so whilst the propergation could have been quicker the 'actual' observed pattern was-

The zonal wind increased significantly from 10M/S on the 4th to 55M/S on the 23rd-

IMG_1168.PNGIMG_1169.PNG

& the AO shows a near perfect match with its profile- launching upwards on the 6th & peaking at plus 4.5- which is in the top 15 readings of all time....

IMG_1166.PNG

Using the above strat chart again-

IMG_1169.PNG

The zonal mean returns to the 'mean' climo late in the first week of Jan so perhaps contrary to Ian/Meto data suggested above the vortex will be going from strong to average - hence again the AO response back to the neutral zone -

So... no disconnect before-? No disconnect now....

* MLB chances 'average'

*HLB / Cross polar chances 'low'- & hence why the ECM has moved away from the split flow it had yesterday at day 10-

MJO still in COD-

S

 

 

 

Edited by Steve Murr

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  

×
×
  • Create New...