Model Output Discussion - 10th Jan Onwards

[Man With Beard]

Until the models decisively move in a Scandi High or show the Atlantic steamrolling the pattern, this will run and run, as the models want to place us on a very thin dividing line between east and west regimes. It may be 2 or 3 days before we are any wiser about the early part of next week. A look at historical charts would not rule out either of the possibilities mentioned above. To get a really good build of heights from the east in our direction will require some luck in the timing and positioning of the High and Low, so last night's ECM remains an outsider, though a weaker easterly remains well in the running. We would want to see a little more of the energy in the split low at T144 going south in order to encourage an easterly.

[IDO]

The non-easterly of this week was handled poorly by the models, now the second shot in week 2 is all over the place. The problem with the ECM is that it churns out the most amplified runs through its op and there is a misnomer that D8-10 charts from this source are of much worth; they are not, proved time and time again when there is a pattern change. Thanks to IF we knew there was only 15% chance of an easterly in week 2 from the ens so I for one will continue to dismiss those FI easterlies the op loves throwing our way.

 

GFS rarely fly with the most amped runs for their op, but you can usually find them hidden away in their GEFS, some today at T168:

 

  

 

   

 

 

As the experts say there is much uncertainty between opposing forces, but that does not mean that an (quasi) easterly is still likely, it remains a possibility, along with other options, and still the most likely, a return to a zonal flow centered somewhere over the UK.

 

However a weaker PV, warming in the strat and amplification upstream from the Bering Sea suggests that Feb will bring a change.

[nick sussex]

Two steps forward and one step back today and more disagreements upstream from quite early on, the UKMO is flatter over there at T96hrs then the general guidance.

 

Thereafter the ECM drags its heels with the clearance of shortwave energy near the UK and its too close for comfort, later it begins to flatten the USA west coast ridge which isn't expected to happen and brings alot more energy eastwards, the GFS is similar and then repeats last nights output.

 

There are timing issues and phasing issues upstream with an inability of the models to just agree on the pattern over the ne USA.

 

At worst I expect to see troughing heading se towards Iberia and not bulldozing its way east, if you go on the expected pattern over in the USA thats a closer correlation than what the models want to do currently.

 

We'll see later on whether they go for that option.

 

A very encouraging ECM ensemble mean this morning, given that some of the flatter solutions will dilute the synoptics.

 

I think its all down to the clearance of that shortwave energy around the T144hrs mark, that clears energy will head se and the block will be further west.

Edited January 14, 2014 by nick sussex

[Gibby]

Good morning. Here is this morning's guide through the output from the big 5 NWP models for today Tuesday January 14th 2014 taken from http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models continue the changeable theme of weather for the next week or so. Low pressure remains in control of the weather though a ridge of High pressure crossing East today will give a dry and fine day for many with an early frost under light winds. Tonight a warm front crosses East with rain and drizzle for all before the cold front follows tomorrow with further outbreaks of rain. Temperatures will become mild melting hill snow settled over Northern Britain. Through the remainder of the week and weekend Low pressure remains close to NW Britain with showers or longer spells of rain in all areas and temperatures never far from average in mostly South or SW winds. Further flooding issues are a risk in the South and West in particular.

 

GFS then shows a drier and colder interlude early in the week being quickly replaced by strong winds and more unsettled weather with spells of rain and showers at times for the rest of the period. It may feel rather cold at times especially in the North with some snow on higher ground at times.

 

The GFS Ensembles remain tightly packed in agreement on average temperatures in an Atlantic based pattern throughout the run this morning. All areas remain at risk of further rain and showers throughout the period with no prospect of any significant change to drier or colder conditions anytime soon.

 

UKMO closes it's run next Monday with Low pressure well established to the NW of Britain with an unstable Westerly airflow over the UK carrying alternating spells of rain and showers mixed with short drier spells in temperatures close to average.

 

GEM today shows more settled conditions developing next week as pressure builds from the SW with High pressure over the UK by Day 10 with frost and fog by night and some dry and bright days with sunshine. Though improvements in the South start quite early next week things take rather longer over Northern Britain.

 

NAVGEM has no such improvements shown with Low pressure continuing to rule the roost with Westerly winds carrying further troughs and attendant rainfall quickly East across the UK followed by showers in temperatures close to or a little below average with some hill snow possible in the north from the showery spells.

 

ECM today shows a very changeable pattern next week and after a brief drier and colder interlude to start the week next Monday the weather becomes unsettled and windy with spells of rain and showers again as Low pressure moves across close to the North with strong Westerly winds in average temperatures once more.

 

The ECM 9 and 10 Day Mean Charts show a similar pattern as last night pulling the pattern slightly East while maintaining the bias towards Low pressure to the NW with Low pressure troughing lying SE down across the East of the UK and North Sea with further rain at times for all the most likely result.

 

http://www.wetterzentrale.de/pics/Reem2161.gif

http://www.wetterzentrale.de/pics/Reem2401.gif  

 

The Jet Stream continues to maintain it's theme of crossing the Atlantic, moving SE to the SW of the UK then East across Southern Europe for some considerable time yet. Later the trend seems for it to tilt more to a East or NE direction across the UK as Low pressure moves East North of Britain through Week 2.

 

In Summary the pattern remains locked at the moment in a generally unsettled period with rain and showers at times for all areas. Temperatures never look to be far from average as one would expect with a basically Westerly bias to the winds over the period in association with Low pressure mostly close to Northern Britain throughout. It's GEM's turn today for it's operational to show something rather different with High pressure settling things down next week with fine days and night frost and fog but it is looking very isolated in the overall scheme of things this morning. For those looking for snowfall you will continue to have to travel to the hills and mountains of the North at times with even here only limited amounts in the polar maritime air masses that pass through at times.

[TEITS]

Still unimpressed with the output including last nights ECM.

 

The block to our NE still does not look like bringing anything wintry and in my opinion is only delaying the inevitable return of a more mobile W,ly pattern. The only positive is the delay reduces the chances of further flooding.

[Summer Sun]

Looks like ECM was a rouge run last night with those 850's

 

[mulzy]

Slightly disappointing output this morning especially the later stages of the ECMWF operational.

 

The ECM mean is still decent at days 7-10, though the pattern has edged slightly east - plenty of time for things to correct west again.

[warrenb]

Subtle and I mean subtle shift in strength of the jet stream will mean the waxing and waning (east/west movement) over the next few days. I would go for a halfway house of just below average but wet with the trough basically on top of us.

[Cumulonimbus Tower]

I think what we are seeing from the models at the moment  is a very finely balanced position where the BI is of the boundary between the colder air to the East and the relatively milder stuff coming in off the Atlantic. That said, some of the Polar Maritime air approaching from the west looks cold enough for winteryness at times over elevated areas. I think the models will keep correcting back and forth and we shall not really know the outcome until it happens. I would be very surprised though if some areas don't see a bit of snow from the end of next weekend onward. There is always the chance that it will all be corrected West again leaving most in the colder air but only time will tell. I'm fairly intrigued at the moment tbh. and aint letting my mood go up and down with every run. Have some faith in the pattern you see!

Edited January 14, 2014 by Cumulonimbus Tower

[The Eagle]

Under the only mild sector in the whole far north atlantic. There is a joke here somewhere i'm sure.

 

 

Will we get the change that makes the difference today? Roll on the 12z's.

Edited January 14, 2014 by The Eagle

[nick sussex]

The GFS 06hrs run is resolute in refusing to clear shortwave energy but even with this its still much better than the 00hrs run and more energy is held back west.

 

The difference between a clearance and non clearance is huge because then a lot of the energy will head se under the block, and the high will be further west, you can see that shortwave energy just sits there for days.

[snowmadchrisuk]

Notice lately on the GFS it keeps wanting to aline the Vortex in such a way that we pull in Cold NW'lys , would be Cold enough for snow and looks like a showery flow . This will do me for a start . 

An example Cold NW'ly from the 6z 

 

[Bristawl Si]

 

Notice lately on the GFS it keeps wanting to aline the Vortex in such a way that we pull in Cold NW'lys , would be Cold enough for snow and looks like a showery flow . This will do me for a start .

I think John Holmes was alluding to this a few days ago, that he felt this was the more likely direction of the UK receiving colder temps, rather than from the East or NE. Apologies if i've 'misquoted' JH. Edited January 14, 2014 by Bristle boy

[stodge]

Morning all

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014011406/gfsnh-0-150.png?6

 

This is for me the critical moment of the current evolution as shown on the 06Z Operational. The lobe of HP over Finland which broke away from the main central Asian HP is set and established  but the orientation isn't brilliant for us. That said, it's strong and supported by lower heights to the SE and SW. Pressure is rising over the UK as the trough dissipates but then:

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014011406/gfsnh-0-162.png?6

 

Up pops a little feature in the North Sea and that's that. GEM this morning offered the possibility of a more anticyclonic evolution IF the trough fully dissipates and this is for me still an option.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014011400/ECM1-168.GIF?14-12

 

ECM this morning got near to it as well but again not quite. It will be interesting to see how this plays out on the afternoon and evening output.

[nick sussex]

Morning all

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014011406/gfsnh-0-150.png?6

 

This is for me the critical moment of the current evolution as shown on the 06Z Operational. The lobe of HP over Finland which broke away from the main central Asian HP is set and established  but the orientation isn't brilliant for us. That said, it's strong and supported by lower heights to the SE and SW. Pressure is rising over the UK as the trough dissipates but then:

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014011406/gfsnh-0-162.png?6

 

Up pops a little feature in the North Sea and that's that. GEM this morning offered the possibility of a more anticyclonic evolution IF the trough fully dissipates and this is for me still an option.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014011400/ECM1-168.GIF?14-12

 

ECM this morning got near to it as well but again not quite. It will be interesting to see how this plays out on the afternoon and evening output.

The GEM is more reflective of the expected upstream pattern and in terms of the NH is quite close to last nights ECM operational run, if you factor in model bias at longer timeframes with energy distribution then theres a better chance of a clearance of that shortwave energy that you highlighted over the North Sea.

[nick sussex]

I thought this quote from NCEP summed things up nicely in relation to the models and their current upstream performance:

 

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...MUCH OF THE LONG TERM PORTION OF THE FORECAST LOOKS TO FEATURE ARATHER CHAOTIC PATTERN WITH LOW PREDICTABILITY. 

[Joe Levy]

The stratospheric warming is still there in the latter stages of the GFS 6z, beginning on around the 26th through to the end of the run

[492]

The block that is expected to develop over N Scandinavia is not predicted to be in place until 2 days from now at the earliest. It is not until it is in place that we may start to know what its effects will be on the behaviour of the UK trough and the possible disruption that may occur. Current analysis shows a high of 1042 MB centred over Greenland with weak high cells futher east. The modelling has proven to be unreliable over the last week with some centres  forecasting (the currently non existant) block to the NE to slip away SE. I think we need to closely watch developments over the next 48-72 hours to see what happens regarding the block. Also the presence of very cold surface air already in place over Scandinavia must have some impact on any blocking in the region.           

[snowmadchrisuk]

I thought this quote from NCEP summed things up nicely in relation to the models and their current upstream performance:

 

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...MUCH OF THE LONG TERM PORTION OF THE FORECAST LOOKS TO FEATURE ARATHER CHAOTIC PATTERN WITH LOW PREDICTABILITY. 

I wonder if they still have high confidence on the more amplified flow over the pacific , you posted it was 5 out of 5 last night I think . Will have to bookmark all these important discussion pages.  

[YorkshireLiving]

The stratospheric warming is still there in the latter stages of the GFS 6z, beginning on around the 26th through to the end of the run

The warming looks slightly stronger than when I last looked a few days ago. Do others think the same and  can someone enlighten me as to timescale for possible (note the word possile) influence on our weather, Thank you.

[Joe Levy]

The warming looks slightly stronger than when I last looked a few days ago. Do others think the same and  can someone enlighten me as to timescale for possible (note the word possile) influence on our weather, Thank you.

 It has been shown to be this strong in the last couple of days, and its strength varies from run to run, but its appearance has been consistent and is in line with hints from those at the Met Office. In terms of timescale, it is fairly difficult to know for certain. If there is rapid downwelling from the stratosphere into the troposphere, then it will be much quicker. However, between a week and two weeks is the best rough timescale I can give you with my limited knowledge. I would say that the second week of February is one to watch, should this come to fruition.

[IDO]

Recent Tweet IF:

 

  fergieweather
Just a 10% chance of colder E/SE'rly flow from more blocked solutions in latest @metoffice assessment looking ahead through next fortnight.
14/01/2014 11:33

 

 

The London Ens from ECM:  

 

The ECM op last night was an outlier in terms of an easterly, this mornings is again an extreme, of the colder cluster (D6-D8).

 

The extended temps mean looks average to cool. However with all the uncertainty the mean is not much help apart from a trend purview.

 

No model is currently predicting a deep cold spell before month's end, the GEFS 06z for instance:  

 

However still lots of fluidity so exact synoptics still not certain.

 

 

 

 

[SLEETY]

well none of the models have been any good past +96 for a while now so why should we believe what they are predicting for the next TWO weeks

 

Do the met have a crtystal ball?

[Summer Sun]

well none of the models have been any good past +96 for a while now so why should we believe what they are predicting for the next TWO weeks

 

Do the met have a crystal ball?

 

No but they correctly predicted no cold this week compared to what the models were showing for a few days last week

 

They also have there in house models like MOGREPS

[IDO]

FWIW deep in FI from ECM mean:     source

 

Interesting times ahead, the US again looking like a continuation of a very harsh Winter. Lots of potential for the UK with those height profiles.

Edited January 14, 2014 by i'm dreaming of...