Model Output Discussion 13/11/13 >

[BLAST FROM THE PAST]

It seems visually true that 06z and 18z runs are poorer than the 00z and 12z and because of four runs a day the GFS certainly chops and changes more than the Euros and maybe accentuates its lack of consistency.  A JH trick of picking one run and following the same time subsequent runs may see it in an improved light...and maybe pick either the 00z or 12z. 

ECM is one hell of a run, and that to me is a point in place...its a hell of a run and I personally won't side with it yet beyond 120/144.  Yes we may nearly get there but UKMO certainly shows the 'nearly' show.  Beyond T120 some model will have egg on its face....we'll know soon enough.  That LP that keeps centering over Italy/Europe keeps us in the cold game.

 

BFTP

[MR EXTREMES]

wow I just come on here think I have a look at the models thinking more doom and gloom wow what a shock fantastic the ecm heights bloody hell now that's a block if that goes in the right place 09/10 rerun im not counting my chickens though im gonna wait a couple of days to see if this firms up but very nice indeed gfs 6z nice ecm nice ukmo getting there but I wait to see if the ukmo goes with the others if not then I think it will be the model closest to the right solution.

[shedhead]

The overnight ECM certainly offers up some decent eye candy, but let's be honest we've not been short of that recently. Still can't see anything that makes HLB any more or less likely than a slow return to zonality as we move into Dec, but until then it appears that cold weather will predominate in one form or another, with quite, frosty conditions still looking like the most likely provider from later this week.

[Summer Sun]

Just so everyone knows ECM is undergoing an upgrade today 12:00 UTC to tomorrow 12:00 UTC along with the EC32

 

 

IFS cycle 40r1 introduces significant changes to the assimilation and forecast model, as detailed below, and two major changes to the ensemble forecast (ENS).

• The vertical resolution and the vertical extent used for the medium-range and monthly ensemble forecasts will change: the number of levels of the ENS will increase from 62 to 91with the model top raised from 5 hPa to 0.01 hPa. The pressure levels remain unchanged.
   
• The atmosphere-ocean coupling of the ENS will be active from initial time of the forecast using a new version of the NEMO ocean model.

These changes do not apply to the Long-range (SEAS) forecast.

With the implementation of cycle 40r1:

• [*]

ensemble forecast tube products will no longer be offered in dissemination: see Impact on users - Dissemination; [*]some MARS streams with be discontinued: see Impact on users - MARS

The first operational run using the new cycle will be the 06 UTC analysis and forecast in the Boundary Conditions optional programme on 19 November followed by the 12 UTC main assimilation and forecast. The monthly forecast extension to the ensemble will be run with the new IFS cycle for the first time the following Thursday, 21 November 2013.

 

In order to manage the transition, changes to dissemination requirements will be suspended from 12:00 UTC on 18 November 2013 until 12:00 UTC on 19 November 2013.

 

 

 

http://www.ecmwf.int/products/changes/ifs_cycle_40r1/

Edited November 18, 2013 by Summer Sun

[snowmadchrisuk]

The ECM is a very good run if you want to see some Snow, although it doesn't look to me like a pattern that would hold for more than a couple of days , more than likely the pattern would die a slow death , with the High continuing East, the Uppers would then slowly get mixed out as low pressure approaches from the West.

 

You really need to see High pressure moving West not East for the long term setups. 

Edited November 18, 2013 by snowmadchrisuk

[ARNOTT ad]

Just so everyone knows ECM is undergoing an tomorrow (Tuesday 19th) along with the EC32 http://www.ecmwf.int/products/changes/ifs_cycle_40r1/

So in summary....??? We still get the ec runs tonight though??

[johnholmes]

It seems visually true that 06z and 18z runs are poorer than the 00z and 12z and because of four runs a day the GFS certainly chops and changes more than the Euros and maybe accentuates its lack of consistency.  A JH trick of picking one run and following the same time subsequent runs may see it in an improved light...and maybe pick either the 00z or 12z. 

ECM is one hell of a run, and that to me is a point in place...its a hell of a run and I personally won't side with it yet beyond 120/144.  Yes we may nearly get there but UKMO certainly shows the 'nearly' show.  Beyond T120 some model will have egg on its face....we'll know soon enough.  That LP that keeps centering over Italy/Europe keeps us in the cold game.

 

BFTP

 

re the same run idea

I know my view upsets some folk but beyond T+144 then you will get usually a more consistent output than comparing each run. Which you choose is up to you. I chose the 12z some years ago mainly because it was the one I could pretty much guarantee being around to look at. Below T+144/168 then by all means look at each model run, look for continuity, look for a pattern, not for identical surface feature positions. As the time scale counts down ALL the models will start to converge until obviously at T+00 they are identical.Using the ensemle outputs can also help get an idea of what pattern each model is appearing to settle on. As with any model use it is the assessment and subsequent analysis of the probability of an actual chart happening, whatever its time scale, that is the key. All of us, and the professionals get it wrong at times. No disgrace in that, simply acknowledge it and move on, diont' just make a big scene when a forecast is correct because you/I will certainly end up with egg on our face not too far in the future. In human terms and the complexity of the weather NO ONE can predict more than 24 sometimes 48 hours in advance without using a computer.

[Yarmy]

Just had a look at the FIM T120, which I think is the proposed replacement for the GFS?. Quite hard to read, but perhaps unsurprisingly looks most like the GFS 0z?

 

 

The surface pressure chart is like far out, man.

 

 

[Frosty.]

The GEFS 06z mean becomes anticyclonic with night frosts from later this week onwards, a very benign outlook with an increasing risk of fog.

[Mapantz]

So in summary....??? We still get the ec runs tonight though??

 

I doubt it, the upgrade says from 12:00 UTC today to 12:00 UTC tomorrow. Tomorrow's 12Z will be using the new upgrade. 

Edited November 18, 2013 by Mapantz

[bluearmy]

large spread on ecm ens london temps as we head from nov into dec.  looking at exeter's update stoday, i doubt the new ecm ens (which they undoubtedly have sight of) are showing much different. judging by ian's info re mogreps-15 on saturday, they see a gradual erosion of the blocking allowing a westerly flow to take over.

[shaky]

I doubt it, the upgrade says from 12:00 UTC today to 12:00 UTC tomorrow. Tomorrow's 12Z will be using the new upgrade.

so does that mean there is no ecm tonight??

[Summer Sun]

so does that mean there is no ecm tonight??

 

ECM should be still out as normal tomorrows 12z run will have the new data in it

[Yarmy]

ECM should be still out as normal tomorrows 12z run will have the new data in it

 

Yeah, don't recall any outages on previous upgrades and presumably they've been running the new version in parallel for a while anyway.

[Frosty.]

There has been no movement towards the ecm from the GEFS 06z perturbations, most of them show normal late autumn anticyclonic weather, nothing unusual or exciting.

[radiohead]

Regardless of what happens, this makes for great model watching. It's the differences between the models that makes all this interesting, and at times exciting. If we knew 100% exactly what was going to happen it wouldn't be half as much fun!

 

The ECM model upgrade tomorrow sounds like it will help a lot with strat forecasts, it will be interesting to see what the guys in the strat thread make of it.

[Mapantz]

Yeah, don't recall any outages on previous upgrades and presumably they've been running the new version in parallel for a while anyway.

 

Good point!  I forgot about previous upgrades, it might be worth saving tonights run and comparing it with tomorrow's upgraded one, although, the ECM might completely change it's mind regardless of the upgrade. 

[MR EXTREMES]

ba if the ecm is right out to the end of its run that block is a 1045mb its a bloody strong block id thought it will stick around for sometime its more where its ends up and agree theres to much low pressure to our north.

 

lol I gotta laugh at the express but it could be a case of a near miss.

 

the gfs 6z had a very deep low running down the country would be pretty cold and very windy but where this goes and where the other alantic shortwaves go is another area to be looking at I still think its game on purely because all this energy floating around has to go somewhere if it suddenly lands in the right place then it could be a good chance, at the moment id say fi is beyond t72hrs.

 

although frostys lower expectations is not been common place shame because I enjoy his ramps.

Edited November 18, 2013 by model rollercoaster

[swfc]

large spread on ecm ens london temps as we head from nov into dec.  looking at exeter's update stoday, i doubt the new ecm ens (which they undoubtedly have sight of) are showing much different. judging by ian's info re mogreps-15 on saturday, they see a gradual erosion of the blocking allowing a westerly flow to take over.

Hi bluearmy.Excuse my ignorance but does the lack of consistent output by all models over say 72 -140 hours leave this update or projected forecast at best on dodgy ground?thanks

Edited November 18, 2013 by swfc

[Frosty.]

I'm just reporting what I see, apart from the ecm there is nothing to ramp...wonder if mogreps is still gunning for that relatively milder mid range outlook.

[radiohead]

98L has been upgraded to 90% probability of becoming a tropical/subtropical cyclone within the next 48 hours. A more intense low could head more poleward, but might also add more WAA too?

[stodge]

I'm just reporting what I see, apart from the ecm there is nothing to ramp...wonder if mogreps is still gunning for that relatively milder mid range outlook.

 

It would be astonishing if at some point we didn't see a spell and perhaps a protracted spell of W'ly or SW'ly winds. Even the most severe winters usually contain periods of milder and more or less wetter weather. Last winter, we went four weeks from mid-December to mid-January in such conditions and the very cold November-December 2010 was followed by a benign January 2011.

 

The overwhelming majority of winters that become memorable are predicated on 7-10 days of very cold and snowy weather for most of lowland Britain (62/63 is an obvious exception). Such conditions can be severe enough and last long enough to produce a very low CET but generally the cold spells are sandwiched between milder spells.

 

The beginning of December is often mild - I believe 18c has been recorded in favoured areas such as North Wales or North Devon which do well from a long fetch SW'ly. On that basis, I can understand the MOGREPS summary of a return to a more Atlantic-based type as that would be the form horse. If the HP block declines to the south or to the west, the Atlantic comes in. An Eastward migration would achieve the same so you're betting agsainst the prevailing jet if you think retrogression or a Northward movement is going to happen.

 

Indeed, the more favoured route for very cold conditions via HP is for the cell to migrate NE from Iberia/Azores into Scandinavia - that has happened before.

[Summer Sun]

I'm just reporting what I see, apart from the ecm there is nothing to ramp...wonder if mogreps is still gunning for that relatively milder mid range outlook.

 

Ian has tweeted the met still going for a return to average temps

 

they (met office) still go with return to average temps into 10-15d period albeit uncertain timings

 

So MOGREPS must still be going for a return to something more normal

[Jax]

FIM output (for a giggle) seems to keep the precip north (mainly) but cold none the less

 

 

[Purga]

The overnight ECM certainly offers up some decent eye candy, but let's be honest we've not been short of that recently. Still can't see anything that makes HLB any more or less likely than a slow return to zonality as we move into Dec, but until then it appears that cold weather will predominate in one form or another, with quite, frosty conditions still looking like the most likely provider from later this week.

That's unless we just end up with a 'cloudy High' God forbid!

 

 

Cool dank days and mild nights