Model Output Discussion 1st Nov.2013

[Summer Sun]

Anybody heard from Dave aka Teits yet?.Its about this time of the year he re-surfaced on this thread lol.Hopd he's ok.

 

According to his profile he was last active here on October 3rd and has not posted since September 20th

 

http://forum.netweather.tv/user/1766-teits/

[Frosty.]

TEITS will return when the Beast from the East begins to roarrrrrrrrrrr

[sundog]

i like the forcasted trend from the middle of the month with the NAO.

[bluearmy]

Hope dave is ok.

Wrt the the ECM 00z op, I rather doubt that a run which delivers daytime maxes to London of 3c day 10 will not be an outlier of sorts (perhaps 5% support which we will have to wait until after 11am to see on the London graph. Holland inconclusive)

Thanks for showing the failed easterly from last dec Karl!

Edited November 9, 2013 by bluearmy

[nick sussex]

At last some cold interest showing in the output with the ECM starting this changeover from as early as 168hrs. Recently the ECM has had some more favourable charts showing at days 9 and 10 but these have remained marooned and haven't moved forward.

Overall its looking likely that there will be some retrogression of high pressure but the issue really is how much, this is more the point of uncertainty allied to the degree of amplification upstream in the USA.

So I think its likely we will see a scenario of retrogression then the high toppling, the further north and west the high retrogresses the better chance of advecting some cold in from the east as this topples.

[draztik]

Taking a look at the GEFS Ensemble mean charts, it appears HP will likely dominate through the next couple of weeks.

 

GEFS 0z Days 0-16

[BLAST FROM THE PAST]

Whilst the ECM operational might want to deliver something cold from the north, the anomaly and ensemble remain uninterested like last night and instead they keep high pressure over the UK

 

Anomaly

 

 

Ensemble

 

Sorry to repost the whole thing but the anomalies will help to display some thoughts.  I think that [particularly me] those of us going for very mild Nov may be scuppered by a spanner in the works to temper the temps and a cooler then milder etc run will occur...

I have a Euro HP interacting with AZH to develop and dominate but I felt that it would be classic zoneality with SW'ly regime.  Now the important feature is a LP sat over Italy...shown nicely on the anomaly charts and also here.

 

This serving to prop up the HP.  Now what we see is that the core of the heights are centred to out SW.  This aloows at times LP to run over the top into the UK bringing a NW'ly like this

 

 

Now because of the anomaly of LP over Italy/Med it acts like a magnet and the LPs that run over the top and into Europe gets sucked down there and we get this.

 

onto this, look how the HP to our SW is trying to ridge and link into Scandi.  It moves onto this

 

 

LP over Italy reset, a flattening of the pattern a bit but almost a continental flow to develop for southern UK.  Another NW'ly flow

 

 

 

HP to SW pulls away a bit, LP anomaly continues over Italy, where is this system over the  going to head after this.  The core goes Lapland, the 'magnet' entices a cut off movement towards Italy with HP in Eastern Europe holding firm.  The movement brings a northerly

 

 

and then onto this

 

 

Bingo, colder set up.  Now some other models aren't as stark and ECM looks on the cold side but illustrates potential effects, the theme is there with this LP anomaly over Italy on most models.  It will, if it holds, allow an up and down run of temps at the least and prevent a Bartlett 3000 mile run of SW'lies dominating.  It may develop into something more meaty or it may carry on into getting flattened then going round again.  Something to watch and will be more seasonal than my weather from the Bahamas thoughts.

 

BFTP

Edited November 9, 2013 by BLAST FROM THE PAST

[bluearmy]

the london ens are out and the op was about the coldest member at day 10.  this is all a sideshow to the general trend of the ens which now has a growing colder cluster post the 20th.  the less cold options are very unconvincing by the 22nd and yes there is one run which brings an ice day on the 23rd!!  

 

 

those of you wondering how relevant these extended ens (and naefs) are need only look at the projected rainfall for london over the next two weeks. a much drier period seems likely which is something both the ecm ens and naefs have pointed to for quite a while. 

Edited November 9, 2013 by bluearmy

[Frosty.]

  Something to watch and will be more seasonal than my weather from the Bahamas thoughts.

 

BFTP

It's a shame that Bahamas weather wouldn't be as nice as this when it reaches the uk, we would get 3000 miles worth of sw'ly muck.

[shedhead]

The 06 GFS, perhaps not unsurprisingly, still refuses to buy into the N blast touted by the ECM, but at least there remains an overall 'colder' component by this time.

 

Still a long way to go before we see a change to any widespread cold, if at all, but to my mind the drier, quieter and more settled spell flagged to start later next week is becoming increasingly likely.....and looking at GFS it could be here for some considerable time.

[Summer Sun]

T240 from GFS also showing something colder

 

 

ECM at t240 looks colder than GFS

 

 

The 00z GFS ensemble at t240 has high pressure over the UK

 

 

Edited November 9, 2013 by Summer Sun

[damianslaw]

As others have pointed out the models continue to suggest an increasingly drier period for all as we move through next week triggered by the influence of stronger heights moving in from the SW and a less active more diffuse jetstream. Longer term ECM continues to show the development of a northerly by the 18th and GFS isn't far off showing a similiar development - the key factor appears to be lower heights developing over central southern europe - preventing heights from collapsing into central europe and instead being forced to ridge NW towards Greenland - if they have the development of low heights over central/southern europe right then this synoptical evolution is very likely. It is a classic 'meridional' flow with the jetstream buckled.

 

The models over recent days have continued to suggest heights building near and over the country as we move towards mid November - this does now seem very likely to happen which in itself will be a marked pattern change compared to recent weeks where the westerly atlantic onslaught has not relented all a response to changes in the northern hemisphere/pole upstream pattern - especially the influence of the 'aluetian high' which does appear to be exerting pressure on the position of the Polar Vortex.

[Frosty.]

The Ecm 00z ensemble mean shows a very undulating pattern until towards the end of next week with trough..ridge..trough etc.., cooler north atlantic / polar maritime air alternating with tropical maritime, a few frosts during the quieter interludes depending on timing of the ridges arrival. It takes a few bites of the cherry for high pressure from the southwest to get a foothold but it does eventually do so, just in time for next weekend onwards and there is no doubt that the ecm 00z ens mean is much more benign looking than the op towards the end of the run, at least for the southern half of the uk.

Edited November 9, 2013 by Frosty.

[Summer Sun]

The Ecm 00z ensemble mean shows a very undulating pattern until towards the end of next week with trough..ridge..trough etc.., cooler north atlantic / polar maritime air alternating with tropical maritime, a few frosts during the quieter interludes depending on timing of the ridges arrival. It takes a few bites of the cherry for high pressure from the southwest to get a foothold but it does eventually do so, just in time for next weekend onwards and there is no doubt that the ecm 00z ens mean is much more benign looking than the op towards the end of the run, at least for the southern half of the uk.

 

Speaking of ECM Matt Hugo has tweeted this

 

 

EC Clusters all over. 15 members have high pressure over the UK by 240hrs, 13 cool W'ly flow and 23 perhaps going with more of a NW'ly flow

 

So at this stage a NW'ly flow has the most support, with high pressure 2nd and a westerly flow 3rd

[syed2878]

interesting the ecmf 240h output if u guys look at the mets 16-30day forecast there's a bit of interest there too. So the ecmf might be on to something there. Remove if off topic mods.

[Summer Sun]

interesting the ecmf 240h output if u guys look at the mets 16-30day forecast there's a bit of interest there too. So the ecmf might be on to something there. Remove if off topic mods.

 

Its the short term one we need to look at (6 to 15 days) to keep within ECM at t240

 

Today it only talks of snow on northern hills

 

 

UK Outlook for Thursday 14 Nov 2013 to Saturday 23 Nov 2013:

 

An unsettled start to this period with showers and some strong winds. A risk of gales in the northwest where showers will be most frequent and heavy, falling as snow over higher ground. A brief quieter spell of weather seems likely into Friday, with many places staying dry. Thereafter, a return to more changeable conditions, with the best of any dry and bright weather across the south and more in the way of rain and stronger winds further north. It will be cold enough for snow at times across northern hills with a greater risk of frost and fog in the south during clearer spells. Temperatures will be around average by day, but cold at night with frost and fog, especially in the drier south.

 

The bit in red covers ECM around the t216 to t240 period and slightly beyond

Edited November 9, 2013 by Summer Sun

[bluearmy]

we know that the operational is an outlier so why does anyone expect exeter to reflect it in their update ??  seems a fair reflection of the anmoly and ens mean and means that the meto's own models are in broad agreement. of course if there are several clusters present in the ens mean, they will have to make a broad forecast which tends to cover most options.

[Biggin]

Hope dave is ok.

Wrt the the ECM 00z op, I rather doubt that a run which delivers daytime maxes to London of 3c day 10 will not be an outlier of sorts (perhaps 5% support which we will have to wait until after 11am to see on the London graph. Holland inconclusive)

Thanks for showing the failed easterly from last dec Karl!

Teits is ok He posts a fair bit on twitter, Mainly bout dead birds and fish  Oops sorry thats Yampkin.

Edited November 9, 2013 by Biggin

[Frosty.]

The Gfs 06z op run has it's moments, cold air occasionally clipping the far north & east of the uk during the next week or so with a brief wintry blast for northern uk in FI, there is then a moment when things could have become very interesting with an undercutting low and a high pressure cell to the north of the uk pushing east into scandinavia. I think something could be brewing during the second half of the month, at least the 6z shows a rather cold trend from mid month onwards with more frost risk, not much sign of sw'ly mush thankfully.

[Frosty.]

Attention all COLDIES....Feast your eyes on these tasty morsels from the GEFS 06z perturbations which also make the 6z mean look rather more promising for cold. There are some exciting outcomes here, Northerly blasts, jet digging well south with a chance of undercut lows.., there are several more charts I could have posted which show potential for cold blasts but these are the most developed. Something is going to change soon with much more potential for wintry weather towards the final third of the month, temps gradually on the slide from mid month with a higher risk of frost and yes.... snow.  

[Duane S.]

Its the short term one we need to look at (6 to 15 days) to keep within ECM at t240

 

Today it only talks of snow on northern hills 

 

The bit in red covers ECM around the t216 to t240 period and slightly beyond

 

Why on earth would the METO change their forecast to reflect today to something like what the ECM showed? They would have had to have seen a much much stronger and consistent signal pointing to cold that anybody on here has seen.

 

Their forecast IMO is about as much of a 'ramp' that we could possibly have expected from them, all things considered. They will (quite rightly) only change to a more bullish cold forecast if and when the probabilities increase significantly enough.

Edited November 9, 2013 by s4lancia

[Cloud 10]

Attention all COLDIES....Feast your eyes on these tasty morsels from the GEFS 06z perturbations which also make the 6z mean look rather more promising for cold. There are some exciting outcomes here, Northerly blasts, jet digging well south with a chance of undercut lows.., there are several more charts I could have posted which show potential for cold blasts but these are the most developed. Something is going to change soon with much more potential for wintry weather towards the final third of the month, temps gradually on the slide from mid month with a higher risk of frost and yes.... snow.  

 

Ensemble 11 is my favourite. 

 

 

 

 

Great post by BFTP earlier. 

[Tom Jarvis]

I sense a Steve murr boom could be coming out of hibernation soon. maybe within the next two weeks

[MR EXTREMES]

I sense a Steve murr boom could be coming out of hibernation soon. maybe within the next two weeks

indeed when the charts start to show the colder stuff before 240hr because its been stuck way out in fi for most of this week.

but settled in th south does look like a possibility but anything exciting is still far far from the realistic outlook as the ukmo has suggested.

[BlueHedgehog074]

The GEM 00Z doesn't follow 00Z ECMWF's Northerly and North-Easterly ideas around the 216 to 240 hour mark. Nevertheless, it does look as though it could develop a Northerly beyond 240 hours with that Low from Iceland looking as though it would swing down South-Eastwards towards the UK/Eastern UK:

 

 

(Whole Northern Hemisphere version from Meteocial - ridges of High Pressure in the other areas of the Northern Hemisphere giving the Polar Vortex a bit of a smacking)

 

This could help to further amplify the high out West strengthening the possible developing Northerly flow on that run. Along with the ECMWF, however, the cold blast is still locked away in the dungeons of FI, and I do perhaps think the ECMWF may be being a tad progressive with its Northerly setup. But considering some people have been mentioning about the fact that some of the ensemble suits being consistent about a cool down around the 20th November, and along with the NOAA 8 - 14 day anomaly chart continuing to show an area of amplified higher than average heights to our West, then I feel a colder period of weather will probably be the likely direction we'll head in. I suppose clearly, for fans of cold and snow, we would need to ensure everything runs as smoothly as a set of gears. If one of the gears of the cold spell setup jam (for example, if we don't see the pattern amplify enough, or without the other ridges of High Pressure in the other areas of the Hemisphere giving a helping hand (such as that Aleutian/Alaskan ridge some people spoke of)), then the other gears of the potential cold and (temporarily) blocked setup could jam and it could be 'game over' for a cold and possibly snowy spell.