Model Output Discussion 1200 hrs 15/11/14

[knocker]

The ECM monthly 500mb anomaly update. Enjoy.

 

T240 4th Dec

HP eastern Siberia -pole-northern - Scandinavia. Trough Canada to mid Atlantic and westwards into Pacific. HP eastern seaboard and trough western central  Europe. Surface zonal between low Greenland and HP to south with average temps UK.

 

T408 11th Dec.

HP eastern Siberia-pole-Scandinavia now stretching westward into Greenland. Canadian trough now disrupted with the western European trough exerting greater influence and now covering the UK and eastern Atlantic. Surface still zonal flow with low south of Greenland and shortwave disruptions eastern Atlantic. Average temps but above average Greenland.

 

T576 18th Dec

Now general area of HP eastern Siberia-pole-Scandinavia and encompassing Greenland and NE Canada. European trough moved slightly SE of UK. Surface  zonal flow with weakish trough south of Greenland and temps a tad below average but above in Greenland.

 

T768 26th Dec

Main areas of interest are HP north eastern Canada and trough UK and Europe. Surface zonal with HP cells north and south in Atlantic (relative to UK of course). Temps just below average.

 

Week one PV Russia but dissipates as time goes by until week three, hey, where's it gone?

 

Summary.

 

Fairly nondescript four weeks with a westerly airstream, interspersed with shortwave activity, and average temps.

Edited November 25, 2014 by knocker

[Duane S.]

Yes, thanks Knocker, we were all waiting with baited breath for the ECM monthlies... Out of interest, is that your take on it or are you copying and pasting (including the summary) from elsewhere?

Models all look fine this morning, no major dramas. The theme of strong pressure anomalies in the pole building in the medium term continuing. It certainly doesn't look like we will benefit in the next 10 days or so, thereafter I wouldn't bet against it. Where Arctic heights are involved, the models are generally clueless, more so than normal even.

The AO now looks ( just like 2 weeks ago ) like only peaking at around +1 (despite the wacky positive forecast values, again just like before the previous weak peak) before heading negative (a likely common theme through the winter).

[Polar Maritime]

A very nice Northerly showing around the 8th on this mornings GFSP.

 

Edited November 25, 2014 by Polar Maritime

[knocker]

Yes, thanks Knocker, we were all waiting with baited breath for the ECM monthlies... Out of interest, is that your take on it or are you copying and pasting (including the summary) from elsewhere?

Models all look fine this morning, no major dramas. The theme of strong pressure anomalies in the pole building in the medium term continuing. It certainly doesn't look like we will benefit in the next 10 days or so, thereafter I wouldn't bet against it. Where Arctic heights are involved, the models are generally clueless, more so than normal even.

The AO now looks ( just like 2 weeks ago ) like only peaking at around +1 (despite the wacky positive forecast values, again just like before the previous weak peak) before heading negative (a likely common theme through the winter).

 

It's my take on it and as you know there isn't a biased bone in my body.

Edited November 25, 2014 by knocker

[bluearmy]

Re the ECM monthly - we only see the ens mean of 51 runs. Very difficult to avoid a zonal type chart past week 2. if looks like the trough becomes based around western Europe. That offers a number of possibilities. chilly and unsettled for the south would be my overall take weeks 3 and 4. and it's December so a sub zero upper flow off the continent on occasions would provide done wintry interest. Uppers will be average to below (0 to -1) through weeks 3 and 4. again, strip out the clusters that are potentially wrong .....

We will get a feel for the clusters from the meto update later.

Edited November 25, 2014 by bluearmy

[knocker]

Yes, thanks Knocker, we were all waiting with baited breath for the ECM monthlies... Out of interest, is that your take on it or are you copying and pasting (including the summary) from elsewhere?

Models all look fine this morning, no major dramas. The theme of strong pressure anomalies in the pole building in the medium term continuing. It certainly doesn't look like we will benefit in the next 10 days or so, thereafter I wouldn't bet against it. Where Arctic heights are involved, the models are generally clueless, more so than normal even.

The AO now looks ( just like 2 weeks ago ) like only peaking at around +1 (despite the wacky positive forecast values, again just like before the previous weak peak) before heading negative (a likely common theme through the winter).

 

The AO from the (P) courtesy weatherbell.com

[knocker]

Prod the ECM monthly - we only see the ens mean of 51 runs. Very difficult to avoid a zonal type chart past week 2. if looks like the trough becomes based around western Europe. That offers a number of possibilities. chilly and unsettled for the south would be my overall take weeks 3 and 4. and it's December so a sub zero upper flow off the continent on occasions would provide done wintry interest. Uppers will be average to below through weeks 3 and 4.

 

True enough b but I was assuming people would take for granted that detail would be flattened out as one disappears into the future.

[MR EXTREMES]

A very nice Northerly showing around the 8th on this mornings GFSP.

Indeed something I pointed out yesterday in a post northerly possibly progression to a North easterly let's say something like 09/10.

As we see the models show this into a more realistic time frame expect the AO to slowly decline could be a -3 AO value showing within the next 14 days I suspect.

Edited November 25, 2014 by emotional rollercoaster

[EML Network]

Regardless of what happens beyond, it looks like the UK is going to get it's first country wide taste of Winter, just as winter begins. 

 

Wed 3rd Dec ECM 

GFS for 2nd Dec

GEM 3rd Dec

and yesterdays JMA run wasn't a million miles away either...2nd Dec

 

I didn't like the text summary of the ECM monthly update, zonal all the way seems a possibility but unlikely perhaps cool zonality from the North West is an option on the table, but equally so is a far flung Easterly with not much on the bones. 

 

I can't see this stale mate between pressure systems being resolved anytime soon, and a seasonable feel to things early in Dec is FAR better than where we were at that stage last year, who remembers the 5th Dec 2013 !!

 

here's a reminder

 

http://www.youtube.com/watch?v=0_ewdjB2OeY

Edited November 25, 2014 by EML Network

[MR EXTREMES]

Regardless of what happens beyond, it looks like the UK is going to get it's first country wide taste of Winter, just as winter begins. 

 

Wed 3rd Dec ECM 

GFS for 2nd Dec

GEM 3rd Dec

and yesterdays JMA run wasn't a million miles away either...2nd Dec

 

I didn't like the text summary of the ECM monthly update, zonal all the way seems a possibility but unlikely perhaps cool zonality from the North West is an option on the table, but equally so is a far flung Easterly with not much on the bones. 

 

I can't see this stale mate between pressure systems being resolved anytime soon, and a seasonable feel to things early in Dec is FAR better than where we were at that stage last year, who remembers the 5th Dec 2013 !!

 

here's a reminder

 

Must agree incredible consistent runs now.

And once in place cold is a bugger to shift

[MattH]

Just a quick one but to place emphasis on what a few have said; be wary of 'reviews' of the EC 32 as the one on the previous page doesn't match with the full EC 32 which shows a very meridional pattern with a blocking high to the E and this, now, signals greater than avg pressure anoms over the UK well into week 2, so hence a more anticyclonic outlook from the EC32. Week 4 has extremely weak signals, even in the full set of data from the ECMWF website. As a result week 4 is like tossing a coin.

I know WeatherBell have the EC 32 and it's good information but it's not the complete set of data as per the ECMWF. This is important as at times there's more to 'things' than what the charts show just on WeatherBell and especially how people interpret it. When I can I'll comment on what the EC32 shows on Twitter but I reluctantly do this as sometimes trying to summarise it in 140 characters is taken out of context or not acknowledged right.

Cheers. Matt.

[knocker]

Just a quick one but to place emphasis on what a few have said; be wary of 'reviews' of the EC 32 as the one on the previous page doesn't match with the full EC 32 which shows a very meridional pattern with a blocking high to the E and this, now, signals greater than avg pressure anoms over the UK well into week 2, so hence a more anticyclonic outlook from the EC32. Week 4 has extremely weak signals, even in the full set of data from the ECMWF website. As a result week 4 is like tossing a coin.

I know WeatherBell have the EC 32 and it's good information but it's not the complete set of data as per the ECMWF. This is important as at times there's more to 'things' than what the charts show just on WeatherBell and especially how people interpret it. When I can I'll comment on what the EC32 shows on Twitter but I reluctantly do this as sometimes trying to summarise it in 140 characters is taken out of context or not acknowledged right.

Cheers. Matt.

 

Thanks and noted. I know what you mean vis a vis twitter.

Edited November 25, 2014 by knocker

[IDO]

With, as expected, the NH flow flattening after the meridional flow courtesy of Nuri, we have a series of pent up areas of HP moving west from upstream. The chart below highlights this:

 

 

So a distinct change from the last two weeks where we have mainly relied on the Azores/sceuro. As they drive west they are forcing the Canadian PV to perk up as well as having the potential to drive WAA north, depending on the phasing with the lower heights. Looks like lasting 7-10 days before the flow slows and we return to the more normal Pacific/Azores/Russian Highs. The GEFS have not got a handle on how this interaction will develop and the members although showing a propensity for at least a MLB offer numerous possible outcomes. D12 for example:  http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=288. 

 

The ECM has a similar setup but with a neutral reaction between the heights and the PV, leading to a flatter flow, meaning we get a MLB over the UK:

 

 

Where as GEM has better phasing with the Atlantic ridge allowing the trigger shortwave low to only send some energy east, and we get a HLB at D10:

 

 

The GEFS are variants on these and include other possibilities, the P and Control providing a brief northerly at the end of FI, due to an Atlantic ridge. So maybe a window of opportunity from the trop to rejig the pattern for a UK cold shot. Too much uncertainty at the moment to be confident though.

[BlueHedgehog074]

Apart from a brief unsettled spell (starting from today in some places) as Low Pressure to the West tries to move up against the block to the North-East, most of the models show High Pressure being mostly in control over the UK - whether this being from High Pressure to the West/South-West or from blocking Highs to the East or North-East. This being particularly notable on the ECMWF this morning as the Mid-Latitude Block sits over the UK to the end of the run. Some models, like the GFS, do show occasions where troughs out North-West will try to find a weak spot in the UK's Low Pressure Shield System â„¢ and try to destroy it (perhaps with the continued possibly of Lows dropping to our South-East).

Yesterday it was chilly Easterlies, but today the 00z GFS Parallel provides a fairly high-quality Northerly for the cold and snow fans in FI. Low Pressure out West drops down into Europe, along with a piece of the Vortex transferring to our North-East. Then see High Pressure amplifying to our West as a result. (Although having not read any of the model posts this morning, wouldn't be surprised if someone else has already posted a chart like this, so apologies if this is the case. Edit: just noticed Polar Maritime's post higher up showing something similar).

Doesn't last too long though as further Lows out West flatten it at the end of the run.

Overall, it looks as though battles between the Atlantic and High Pressure systems will continue, but with High Pressure generally staying quite close by/over the UK at times, some very November-esque conditions could be achieved with the continued likelihood of frosts and mist overnight. I suppose if the Atlantic does break through, though, then certainly a possible chance amplification could develop to the West, especially if the Vortex around the Canadian area weakens.

Edited November 25, 2014 by DiagonalRedLine

[Gibby]

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY TUESDAY NOVEMBER 25TH 2014.

NEXT UPDATE WEDNESDAY NOVEMBER 26TH 08:00

THE CURRENT GENERAL SITUATION A wave depression is forming over the English Channel, moving NNE through the next 24 hours towards the North Sea later tomorrow.

MODELS-2 WEEK HEADLINE Generally changeable conditions look likely across the UK though the emhasis should be on more dry weather than wet with temperatures close to average though below where any mist, fog or frost patches develop later.

THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast shows the flow remaining weak around the UK and Europe for the remainder of the week. The trend thereafter remains for it to increase and push further East over the Atlantic, UK and Northern Europe in the second half of the period.

GFS OPERATIONAL The GFS operational this morning shows disrupting Low pressure to the West of the UK by the weekend following the slack and Low pressure across the UK over the next few days. This disrupting Low pressure then is split into a cut off Low over Iberia while another portion moves harmlessly away to the North allowing a ridge of High pressure to reform over the UK from the European High pressure block at the weekend. Later in the period High pressure remains the driving force of the weather over the UK gradually forming a centre either over or close to the UK with some cold and frosty conditions likely to develop for many as a result with patchy fog problems too.

THE GFS PARALLEL RUN The GFS Parallel run is in unison with the operational in the first half of the period before High pressure develops more towards the SW allowing the Jet flow to override and collapse the European High pressure. This then makes for a milder WSW flow across Northern areas extending South at times with some rain at times, more especially across the North. Later in the run a deep Low diving SE over the North Sea introduces a plunge of cold Polar air across the UK with keen North winds and showers or longer spells of rain, sleet and snow in below average temperatures to end the period.

THE GFS CONTROL The GFS control run this morning closer resembles the Parallel run in sequence with a slow transition towards the High to the East giving way to more control towards High pressure close to Southern England. This of course as indicated before allows the Jet flow to cross East into Europe at higher latitudes and allows temperatures to rise on a WSW flow across the UK with rain at times in the north. It is supportive thugh of some form off attack from the North, albeit temporary on this run late in the period with some rain and snow in placesfor a time.

THE GEFS ENSEMBLES The GEFS Ensembles this morning show the most favoured point likely to be held in two weeks from now is the UK to be locked in a trough from Low pressure close to or over the North of the UK with the Jet flow quite well South with unsettled and at times chilly weather with rain at times and snow over Northern hills, though this brought about on a mostly Westerly flow.

UKMO UKMO today shows a strong ridge of High pressure across Eastern Europe, all the way West through the British Isles and with a new centre well out in mid Atlantic at Day 6. Low pressure lies across Spain and over a point North of Iceland. The resultant quiet weather with West winds in the far North and East ones in the far South will leave most of the UK benign with some bright spells along with mist, fog and frost patches developing again with time.

THE FAX CHARTS The Fax Charts show a developing Low pressure over the English Channel over the next 24 hours with a complex array of troughs across the South and East gradually transferring NE in the wake of a strengthening SE flow later in the week as a deep Low complex develops near Spain. pressure is then shown to rise across the UK as a ridge develops across the UK from Europe.

GEM GEM this morning also shows the theme of disrupting Low pressure slipping down over our western Sea areas and arriving over Spain. This sets up an Easterly flow over the South of Britain while a ridge from Europe and later the Atlantic disects te UK with a slacker west flow over the far north. Towards the end of the run pressure falls from both the SE and NW with a complex Low pressure area bringing rain and rather chilly conditions to many before the end of the period in slack cyclonic winds then.

NAVGEM NAVGEM shows a much more marked push of Atlantic weather East across Northern Europe next week as the High over Eastern Europe collapses and allows a displaced Azores High to lie just to the SW of the UK then to become the dominant player in UK conditions with strong Westerly winds with rain at times across the North while the South sees some more lengthy drier periods between very occasional and lighter rain events in average temperatures for all.

ECM ECM this morning also shows a cut off Low feature over Spain at the weekend while the UK lies in centre ground to a ridge from an European High to another one over the Atlantic. On this run there is strong support for the Atlantic High to eventually form a UK based feature with all the attendant Winter issues of fog and frost, widespread, persistent and dense likely to develop across Britain as a result later in the period. This would make conditions very cold locally. Before this develops though a band of cloud and rain from the North is shown to move down over the North and East of the UK towards the middle of next week.

THE ECM ENSEMBLES The Ensemble run shows strong support for much of the UK to be under quiet and anticyclonic conditions in 10 days time with much of the UK likely to have surface air pressure values in excess of 1020mbs. The centre of High pressure will be of paramount of importance as to what conditions will be experienced in any one place at the surface in terms of frost and fog amounts.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS There is still an element of indecision between the models of developments beyond this weekend though the overall general trend is for High pressure is one shape or form to be the overriding factor close to the UK later in the period.

MY THOUGHTS The pattern this morning remains a very complex one with many factors coming into play over and around the UK which could all shape our weather very differently over the period if one factor overpowered another. As it is the models do vary considerably in detail once we leave this weekend which looks like being benign under a ridge from the East. The general belief next week is that there will be a gentle shift towards a new High from the Atlantic playing a more dominat role in the UK weather over the remainder of the period. The positioning of this will be instrumental in the weather type at the surface with differences in opinion on this shown across the models this morning. If the High makes landfall over Britain which is shown by a number of runs then the net result will be quiet and fine weather for the UK but it could well become cold and foggy with frost widespread. This could be reluctant to shift through the day in the light winds. If, however the High is held to the South as is shown by some other output then the Jet flow will overide the system and flatten the pattern to make for mild Atlantic winds to affect the UK with rain at times chiefly in the North. There is also some opinion that the High could move East of the UK and allow Low pressure to slip South over or to the East of the UK later bringing a plunge of colder polar air down from the North for a time late in the period. It really is a case of you pays your money and takes your choice on which theory if any proves correct come the time. It does look increasingly unlikely now that unless the current High pressure over Eastern Europe can gain assistance from a new High pressure centre elsewhere the block over Eastern Europe will probably not deliver anything cold to the UK this time but with plenty of High pressure floating around at our latitude over the next few weeks there is always a chance that these could be drawn to a position more favourable for bringing cold weather to the UK sooner or later albeit home grown anticyclonic cold or from a cold source either from the North or East. As I hinted at yesterday the pattern is far from set at the moment and there remains plenty of interest hemispherically to induce or maintain interest for coldies with I anticipate a cold period likely at some point over the next three to four weeks looking quite likely for the UK perhaps with some snow though that word 'patience' is going to have to take frontstage.

[blizzard81]

A little deflated this morning with regards to this mornings output from a coldies perspective. The theme of the overnight runs is one of way too much energy in the Iceland vicinity. I am wondering if we are going to have a drier version of last winter with azores ridging and Icelandic low - a very positive NAO winter. This ties in with the Meto winter forecast. Just saying!

[bluearmy]

Blizzard - it's the 25/11

Reliable charts don't even make winter yet !!!

[blizzard81]

Just a quick one but to place emphasis on what a few have said; be wary of 'reviews' of the EC 32 as the one on the previous page doesn't match with the full EC 32 which shows a very meridional pattern with a blocking high to the E and this, now, signals greater than avg pressure anoms over the UK well into week 2, so hence a more anticyclonic outlook from the EC32. Week 4 has extremely weak signals, even in the full set of data from the ECMWF website. As a result week 4 is like tossing a coin.

I know WeatherBell have the EC 32 and it's good information but it's not the complete set of data as per the ECMWF. This is important as at times there's more to 'things' than what the charts show just on WeatherBell and especially how people interpret it. When I can I'll comment on what the EC32 shows on Twitter but I reluctantly do this as sometimes trying to summarise it in 140 characters is taken out of context or not acknowledged right.

Cheers. Matt.

Hi Matt, so in a nutshell, the latest ECM monthly hasn't got a clue beyond week two - would that be a fair assessment ?

[blizzard81]

Blizzard - it's the 25/11

Reliable charts don't even make winter yet !!!

Point taken BA but just my assessment on the overnighters. However, like you say, I shouldn't base the whole winter on one set of runs. What's your views on the updated 00z ECM ensembles ?

[MR EXTREMES]

the ao wants to go very neg 

[Summer Sun]

ECM looking very seasonal this morning with frost and fog potentially becoming a hazard next week if you were stuck under the fog temperatures would really struggle

 

 

 

So a seasonal start to winter looks likely which is a huge improvement on 12 months ago

 

[knocker]

Hi Matt, so in a nutshell, the latest ECM monthly hasn't got a clue beyond week two - would that be a fair assessment ?

 

A fair assessment would be exactly what MH said.

Edited November 25, 2014 by knocker

[Chris K]

A little deflated this morning with regards to this mornings output from a coldies perspective. The theme of the overnight runs is one of way too much energy in the Iceland vicinity. I am wondering if we are going to have a drier version of last winter with azores ridging and Icelandic low - a very positive NAO winter. This ties in with the Meto winter forecast. Just saying!

 

Before this starts a whole new debate in this thread again, can I just kindly point out what has been stated several times already recently?

There is not an offical Met Office winter forecast. If I am assuming correctly, you are referring to the 3 month contingency planner release to assist organisations with their risk assessments for POSSIBLE scenarios for the next 3 months, away from typical types of weather.

It should not be taken as an official forecast.

 

"3 month outlook

This product provides some limited guidance on potential variance from climatology i.e. possible change from what is typical for UK weather.

It is however an emerging and cutting edge area of science and users are encouraged to consult our shorter range and climatological guidance before committing resources or taking action."

http://www.metoffice.gov.uk/publicsector/contingency-planners

Edited November 25, 2014 by Chris K

[mushymanrob]

im bemused.... ok i didnt view the later runs yesterday, but this morning there appears to be some broad consensus between the gfs and ecm. and they both appear to signal the demise of the current eastern block as the azores high becomes displaced and ridges over the uk.

 

 

and the gfs

 

that to me looks like it would produce fairly normal average weather for this time of the year. some milder days, some chillier, rather quiet and often gloomy with some fog and frost.

 

but with the predicted demise of the eastern block IF these charts varify, then theres nothing especially cold* on the cards in the forseeable future.

thankfully though, and something that will probably get agreement on from all quarters, its looking mainly dry.

 

* by that i mean particually cold below the normal for the time of year.

Edited November 25, 2014 by mushymanrob

[blizzard81]

the ao wants to go very neg 

To my eye, those look to be split and variable plus that is yesterdays update. Be interesting to see todays but they are prone to large swings just like any forecast.