Model Output Discussion 18z 30/09/15

[SMU]

ECM at 168 is a pretty cold run

Indeed it appears at that timeframe a small area of 528 thicknesses is apparent over the near continent-

The 1019 contour along the 544 height is about 528 thickness ( uppers -6c )

S

[Ali1977]

Impressive looking ECM at 192 - shame it's only mid Oct.

[Mucka]

ECM at 168 is a pretty cold run

Indeed it appears at that timeframe a small area of 528 thicknesses is apparent over the near continent-

image.jpg

The 1019 contour along the 544 height is about 528 thickness ( uppers -6c )

S

 

 

This is a bit different from ECM, what's going on here then?

 

 

GFS ensembles were slightly flatter in FI on the 12z run but the control would have coldies salivating come winter/late autumn.

 

 

Edit.

 

ECM gives the continent a reload, brrRRrrr

 

Edited October 8, 2015 by Mucka

[knocker]

The GEFs anomalies tonight continue with the theme of the last few days. The 6-10 has ridging from the SW over the UK, LP Canada giving a surface analysis of a swathe of HP from the south west through to Scandinavia. The actual detail Depends on where HP cells settle but generally temps below average, In the 11-15 period there is less amplification and the influence of the HP weakens leading to more zonal flow with temps average, Nothing sinister in the woodshed. NOAA would appear to be less inclined to take the zonal option

http://www.tropicaltidbits.com/

 

Edited October 8, 2015 by knocker

[ANYWEATHER]

Good Evening All, So strong ridging across Scandinavia is to influence the Uk in the days ahead.... Thanks to  Ex Hurricane Joaquin   .The Continent is much colder than last year , so a cold flow across the nation next week Via North Easterly/Easterly winds ,picticularly for southern uk and we may be talking wind chill here !   So a Chilly and dry outlook for now, Ecm and Gfs  strongly disagree at T+240....  ./ Ecm  has led the way recently , Gfs has been very poor,.....

Edited October 8, 2015 by ANYWEATHER

[Singularity]

It's nice to see the return of model corrections in favour of disrupting troughs and blocking highs persisting... for a number of years now we've spent a lot of the time seeing corrections go in the other direction. As I just posted in the winter discussion thread, this seems to reflect the state of the background forcing to some extent i.e. when the broad setup is favourable for blocking, the models underestimate the magnitude to which blocking actually occurs, whereas when forcing is unfavourable, the opposite occurs.

 

I suppose I should ask - is it just me who sees this behaviour or is this a genuine model trait?

 

 

Anyway, ECM's det. runs have first delayed and now toned down the push of westerlies from the Atlantic, enough so that we're no longer looking at the 'backside' of a trough combining with a mid-Atlantic ridge in 10 days time.

 

GFS's det. runs continue in steadier form, as they hold on to the theme of slowly retrogressing the mean position of the high across the UK. It looks likely that if ECM was to continue making corrections along the lines seen over the past few days, it too would end up showing us a slowly retrogressing high, as each trough disruption/undercutting low allows the ridge to take a step to the west/northwest.

 

 

This time last year, we had the pre-upgrade GFS det. runs to look at, and it was entirely reasonable to expect that for much of the time, whatever was shown beyond +192 hours was too progressive one way or another, with ridges toppling fast when in reality they would hold on for a bit longer. 

Now, we have the upgraded GFS det. (and any day now GEFS), and having followed this during the latter stages of last winter, I noticed it seemed to spend a roughly equal amount of time being too 'flat zonal' or too amplified with its solutions in the longer range. I actually reckon that some ways this could make it more tricky to anticipate the overall trend beyond a week's range      

[knocker]

The ecm anomaly tonight at T240 isn't quite so emphatic with the ridging over the UK with a weak trough Scandinavia but HP influence from the SW is still the significant factor for the UK. In the ext period this is maintained briefly, probably more so, before towards the end of the period a trough Greenland comes increasingly into play and a more unsettled zonal regime enters the fray. At the moment the ecm appears to be on it's own with this interpretation. The 06z GEFS upgrade keeps the HP until here.

 

 

Edited October 8, 2015 by knocker

[phil nw.]

Good Evening All, So strong ridging across Scandinavia is to influence the Uk in the days ahead.... Thanks to  Ex Hurricane Joaquin   .The Continent is much colder than last year , so a cold flow across the nation next week Via North Easterly/Easterly winds ,picticularly for southern uk and we may be talking wind chill here !   So a Chilly and dry outlook for now, Ecm and Gfs  strongly disagree at T+240....  ./ Ecm  has led the way recently , Gfs has been very poor,.....

 

Some images from NW extra certainly underlining the expected -ve temperature anomalies over the next 9 days AW.

Europe and the UK heading below normal as that colder air filters west around the high over Scandinavia.

 

 

Quite an early cool down for W.Europe.

The effects of a blocking high over Northern Europe deflecting the jetstream and keeping the Atlantic influence at bay and feeding the cold from the east and north.

[johnholmes]

The GEFs anomalies tonight continue with the theme of the last few days. The 6-10 has ridging from the SW over the UK, LP Canada giving a surface analysis of a swathe of HP from the south west through to Scandinavia. The actual detail Depends on where HP cells settle but generally temps below average, In the 11-15 period there is less amplification and the influence of the HP weakens leading to more zonal flow with temps average, Nothing sinister in the woodshed. NOAA would appear to be less inclined to take the zonal option

 

I would be inclined to take the NOAA version as the most likely!

 

 I actually reckon that some ways this could make it more tricky to anticipate the overall trend beyond a week's range

hence why, in my view, I believe the best option for basic upper air ideas and from that the general idea of the 'type' of weather is the 500mb anomaly charts, best are NOAA and then ECMWF-GFS IF it tends to agree with NOAA. Having said that over the past 9 months or so the EC-GFS variant has, at least, 4 times in that period been the leader rather than led by NOAA for the correct upper air pattern at 6-10 days.

Just my opinion and you and other may well disagree with my ideas.

Edited October 8, 2015 by johnholmes

[knocker]

Well you can't accuse last night's GEFS(P) 18z anomalies of sitting on the fence, It takes the current HP set up and shoves it east and develops the mid Atlantic block  It then runs with this through until the 24th which portends a period of quietpleasant weather with the UK within the circulation of the HP centred to the west. Rather cool with temps below average. Looking like a bumper crop of dafs this year.

Charts courtesy weatherbell

Edited October 9, 2015 by knocker

[knocker]

A brief overview of the latest EC32

 

On Thursday 15^th it has the swathe of high pressure Scandinavia to mid Atlantic but also an upper low northern Europe that could impact the southern half of the UK but it will be very transitory if it does and I suspect it is unlikely.

 

It then proceeds to develop the mid Atlantic block and replaces the Scandinavian HP with a trough stretching down into Europe until the 21^st  with temps a little below average.

 

From there on in it quickly weakens the block and develops the Greenland trough which by the end of the month sees the Atlantic  in control with depressions sweeping in the westerly flow with temps around average.

 

The Atlantic then remains the major player until the 9^th of November.

 

Summary

 

High pressure in charge until around the 22^nd  where after the ubiquitous mid Atlantic trough enters the fray heralding a pattern change to Atlantic domination.

[knocker]

The GFS ops this morning can be summed up simply by saying that after a brief sojourn with a cool easterly the rest of the run is dominated by the Atlantic block. And the easterlies aren't that cold.

Chart weatherbell

Edited October 9, 2015 by knocker

[bluearmy]

A brief overview of the latest EC32

 

On Thursday 15^th it has the swathe of high pressure Scandinavia to mid Atlantic but also an upper low northern Europe that could impact the southern half of the UK but it will be very transitory if it does and I suspect it is unlikely.

 

It then proceeds to develop the mid Atlantic block and replaces the Scandinavian HP with a trough stretching down into Europe until the 21^st  with temps a little below average.

 

From there on in it quickly weakens the block and develops the Greenland trough which by the end of the month sees the Atlantic  in control with depressions sweeping in the westerly flow with temps around average.

 

The Atlantic then remains the major player until the 9^th of November.

 

Summary

 

High pressure in charge until around the 22^nd  where after the ubiquitous mid Atlantic trough enters the fray heralding a pattern change to Atlantic domination.

I'm very much of the view that the EC32 in the mean format we see behind the paywall is close to useless as a forecasting tool (beyond week2) most of the time. I have, on occasion, seen the groupage that exists within the suite and this was excellent.

[Ali1977]

ECM not as bullish this morning with regards building heights to our North - as knocker has mentioned, maybe the Atlantic is about to step up a gear later this Month. It's all about what happens to the stubborn Atlantic high and where that heads.

I for one quite like the benign chillier Autumn weather that's coming over the next few days so I hope it hangs on.

[knocker]

I'm very much of the view that the EC32 in the mean format we see behind the paywall is close to useless as a forecasting tool (beyond week2) most of the time. I have, on occasion, seen the groupage that exists within the suite and this was excellent.

 

Not a problem I will desist posting a summary in future as others seem to agree with you.

Edited October 9, 2015 by knocker

[Gibby]

Rather busy again this morning I'm afraid so if someone would like to copy and paste from my website that will be fine otherwise here's a link.

 

http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

[IDO]

Not a problem I will desist posting a summary in future as others seem to agree with you.

 

Yes just a matter of time before the usual Atlantic regime establishes. Both JMA and CFS hint at sometime during the last third of October, early days but ties in with EC32:

 

 

 

I noted the latest EC Winter forecast was also Nov-Jan, above average temps with a westerly flow. Composites for SSTA also have a very strong signal for Nov-Dec for an Atlantic sources flow:

 

  antmasiello

Here are the 500mb anomaly differences for Nov-Dec. http://t.co/FDhWBytujf

08/10/2015, 23:43

 

Just for info purposes as these are at this time of year just for discussion rather than a verifiable forecast.

 

Keep posting the EC32 updates as many of us are interested. Thanks Knocker.

[Geordiesnow]

Bit of a bland outlook in all fairness at the moment, for me, the main trend I seem too see in the long term is for height rises to sink and the jet stream looking a more normal pattern so all rather bog standard stuff really. 

 

The positioning of the high is quite crucial on what type of weather we may have but it does look a dry outlook with chilly nights and perhaps coolish days at times, especially the further East you are. 

[knocker]

The GEFS(P) anomaly this morning keeps the Atlantic block in situ throughout the run. The ext ecm goes part way in agreeing with this but has the HP further south and thus a more zonal solution as it plays around with the Greenland trough.

Chart weatherbell and http://www.tropicaltidbits.com/

 

[knocker]

Yes just a matter of time before the usual Atlantic regime establishes. Both JMA and CFS hint at sometime during the last third of October, early days but ties in with EC32:

 

wk3.wk4_20151007.z500.gif  Y201510.D0712.png

 

I noted the latest EC Winter forecast was also Nov-Jan, above average temps with a westerly flow. Composites for SSTA also have a very strong signal for Nov-Dec for an Atlantic sources flow:

 

  antmasiello

Here are the 500mb anomaly differences for Nov-Dec. http://t.co/FDhWBytujf

08/10/2015, 23:43

 

Just for info purposes as these are at this time of year just for discussion rather than a verifiable forecast.

 

Keep posting the EC32 updates as many of us are interested. Thanks Knocker.

 

Cheers IDO will do.

 

The GEFS(P) anomaly this morning keeps the Atlantic block in situ throughout the run. The ext ecm goes part way in agreeing with this but has the HP further south and thus a more zonal solution as it plays around with the Greenland trough.

Chart weatherbell and http://www.tropicaltidbits.com/

[MR EXTREMES]

broadly speaking most of the models have heights to our west trying to build into southern greenland as nick sussex would say alot matters on depressions leaving the northeast of the states there are signs that a pressure build over the canadian sector although this is later in some models runs.

 

so really its seeing how robust the heights are but my thinking would be not a zonal onslaught infact pretty settled and remaining slightly below average.

 

the later gfs jet stream chart shows how very fragmented and weak it is right through the model runs.

 

the ao also has a majority going neg especially during the very later runs.

 

someone posted some long range monthly charts but to show differences from each model on seasonal long range forecast and the cfs does hint at colder months march jan and November but next month will be interesting if we can continue to squeeze the life out of the powering up vortex at this point.

 

[MR EXTREMES]

the gfs 6z still has heights to our west lows to our east although in fi and not moved any closer in timeframe broadly speaking thats most likely the gfs is not sure how robust heights will be.

 

but from other el nino autumn winter seasons it can be extremely stubbon.

 

so pretty settled and cool below average perhaps the odd day or two of average if we get another pulse of heights move in over the uk then that will lock in the chilly air.

 

although this might be a boring period of weather its still by far not without interest.

Edited October 9, 2015 by emotional rollercoaster

[IDO]

It looks like the El Nino will sustain through the Winter, and as there is currently good coupling between the sea temp and atmosphere, there is a strong signal for the upstream pattern this coming winter.

 

Latest advice on El Nino: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html

 

As this is one of the strongest on records, a signal for a strong +EPO is likely. That without other drivers would more than likely translate to a milder DJF for Europe. A good webcast from WSI goes over this:

 

https://wsi.wistia.com/medias/j27zqgbtom

 

It will be interesting if such a strong El Nino can be overridden by other factors; QBO, Strat, sun spots?

 

 

 

 

[Scorcher]

 

so pretty settled and cool below average perhaps the odd day or two of average if we get another pulse of heights move in over the uk then that will lock in the chilly air.

 

 

It's not going to be warm but to me the models seem to be backing away from anything notably cool- the 0C isotherm seems to struggle to reach us going by this evening's GFS 12Z. I wouldn't be surprised if temperatures reached average in many parts by day next week in any afternoon sunshine, although the nights will be cool.

[Daniel*]

It's not going to be warm but to me the models seem to be backing away from anything notably cool- the 0C isotherm seems to struggle to reach us going by this evening's GFS 12Z. I wouldn't be surprised if temperatures reached average in many parts by day next week in any afternoon sunshine, although the nights will be cool.

Uppers are not fundamental any continental flow will be chilly as the continent is colder this year.

To add welcome back IDO

Edited October 9, 2015 by Daniel*