Model Output Discussion - The Start Of Winter

[knocker]

One had to look carefully this morning to see how GFS handled this forthcoming period of bad weather. Fortunately it may well be quite brief before SWs cut in and average to above average temps ensue.

 

At T126 it starts to develop a low in the North Sea (not for the first time) and by T132 it's fully fledged and both lows swing east and by T168 are history and the UK is in a westerly.

 

Come on ECM - do your duty to Queen and country/

 

Charts courtesy weatherbell

Edited December 7, 2014 by Polar Maritime
To remove reaction comment.

[Barry12]

ECM has changed quite significantly this morning. It gets cold temporarily for the North at day 6 with -4 uppers. Positive uppers for the south, so average to above most likely. Then at day 7 we get a cool NW with probably average temperatures. The UKMO and GFS have heights moving towards Greenland while the ECM doesn't. Until We see the 12z's we shouldn't worry as it's the odd one out. The medium term outlook is a worry though. I think the likes of Tamara have some explaining to do as to why this ded cert pattern change is looking unlikely to happen.

[knocker]

Anyway the ECM develops the low slightly differently but still brings the next system into play as can be seen by the 850mb chart.

 

Courtesy weatherbell

Edited December 7, 2014 by Polar Maritime
To remove off topic comments.

[mushymanrob]

Nothing is certain, the atmosphere is so volatile atm that getting a handle on what might or might not occur later this week. the deep low/storm looks certain, as does the draw of bitterly cold air in its western flank, but models cant agree on whether this is a breif affair or one to last a few days. to my eyes it does look ripe though for a polar low to form frid/sat and track southeastwards delivering me some snow.

Edited December 7, 2014 by Polar Maritime
To remove off topic comments.

[IDO]

I did mention the mean last night did not support a full on Northerly on the ECM and this morning the op is closer to that mean:

 

 

 

Again the ECM op this morning is more in line with its mean at D10 with a flatter zonal pattern:

 

 

Despite my insistence of warning re D8-10 ECM over amplified op charts they keep getting taken at face value by some! Anyway GEM and ECM are back in line with the bigger picture and the consistent long wave pattern that the GEFS have been issuing for many days. GEM at D10:

 

 GEM's take on the Arctic Northerly is not really.

 

The D10 GEFS mean has been rock solid like this morning for around that range: 

 

Support op & C:

 

I still remain convinced the PV mobility in the medium range will prevent any real cold from establishing. The muted signal for something to develop in the last third of December on the FI GEFS is being eroded run by run. The D16 mean: 

 

 

We cannot shake that lobe over the Greenland/NE Canadian area. The warming at 10hPa is from around D11-16. It is holding on at the end of the run so that is promising.

 

Next weekend looks cool for the south but nothing major with the GFS mean similar to last night showing no Arctic Northerly for most:

 

10hpa at D16: mean next weekend:

 

London ensembles

 

Still time for change, but anectdotally Northerly's tend to downgrade from the FI into the reliable.

Edited December 7, 2014 by i'm dreaming of...

[bluearmy]

This morning brings the pendulum back the other way - with the Azores ridging east into Europe and the flow well to our east. Probably too much of a swing and the next two suites will either solidify this or keep us guessing. you might call the 00z runs the 'Exeter runs' as they broadly fit with what Ian has been telling us. Is that MOGREPS doing it's stuff again? It's sometimes not too difficult to predict what the models will be showing tomorrow - Whether they are singing from that hymn sheet the next day is the trick! Extended GEFS anomolys look similar to yesterday's dropping a trough into nw Europe - will make a change! there is potential way way up high and that's for another thread and probably another month as far as events down here are concerned. Hopefully the holiday watching period will be unmissable! (Can we manage a fortnight of not much to watch in the meantime? Though it's never really like that in December)

Edited December 7, 2014 by Polar Maritime
To remove off topic comment.

[nick sussex]

I thought the ECM might backtrack but didn't think it would swing from the best output last night to a horror show of epic proportions this morning.

 

It all unravels as early as T96hrs over Arctic Canada, whats even more shocking for the supposed best model is that it was wrong within T120hrs last night, the UKMO also has backtracked from its output last night, gone is the high to the ne and it looks like its moved to this mornings ECM Freddie Kruger special although not quite as awful.

 

The sum total is that the models reform one PV blob to the north, dreadful stuff all round for coldies this morning.

 

For late risers the smelling salts might be in order as they try and digest todays shocking turn of events!

[knocker]

Anyway-

 

 Matthew Hugo @MattHugo81  Â·

Ensemble models now taking us near to Christmas & the days before *currently* look wet & windy, temps around avg - http://www.wetterzentrale.de/pics/Rz500m16.gif â€¦

Edited December 7, 2014 by Polar Maritime
To remove off topic comments.

[Jason M]

Yep, I agree IDO. 

From looking at the charts over the last few days the striking think actually is that there is pretty much zero signal for HLB! Looking through the ensembles this morning at days 10 and 15 there are maybe one or two that hint at something whereas in nearly all cases pressure remains high to our South and southwest. Indeed, the trend of the last 48 hours amongst the GEFS has been to increase pressure over Iberia. This is very bad for us in terms of anything cold and will make it less likely that any northerly will have any meaningful impact on the south.

In fairness, the strat folk on here have been saying end Dec / early Jan (if I've understood correctly) so it's going to be interesting because the trop based charts are all looking very poor indeed in my view. As of this morning I can't see any prospect of a major cold spell at all. Sure we may squeeze a two day tame northerly, but that's about it.

The point IDO makes about the flattening of the pattern is spot on IMHO as I've seen similar to this many times over the years. As the northerlies come into range the models recognise that the heights to our South will not allow the cold air to come South and it downgrades the event as it enters the 5 day range.

I hope to be wrong, but down here I'm not expecting meaningful snow before new year (regardless of the what GFs precip charts show).

Edited December 7, 2014 by Polar Maritime
To remove off topic comment.

[Polar Maritime]

I have just deleted/edited many posts. Can we stop the silly tit for tat bickering once and for all, And respect others views.  

 

Please continue on from here discussing what the Models are showing. Or your post will go missing.

 

PM. 

Edited December 7, 2014 by Polar Maritime

[dragan]

ECM has North at day 6 with -4 uppers. Much higher uppers for the south, overall average. After this i believe a nw flow which will be cool, not cold.

Edited December 7, 2014 by Polar Maritime
To remove off topic comment.

[MR EXTREMES]

Anyway-

 

 Matthew Hugo @MattHugo81  Â·

Ensemble models now taking us near to Christmas & the days before *currently* look wet & windy, temps around avg - http://www.wetterzentrale.de/pics/Rz500m16.gif â€¦

Temps around average indeed which also mean snow for the North so maybe some wintry weather for the lucky ones at elevations.

[mushymanrob]

I thought the ECM might backtrack but didn't think it would swing from the best output last night to a horror show of epic proportions this morning.

 

 

thats the ecm for you, its been swinging wildly for some time now. we saw this through summer with promises of heatwaves disappearing overnight.  just dont believe the more amplified solutions.

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=6

 

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

 

 

morning  all i say their could be a lot grey hair appear  in here to the run up to Xmas  it  could   go cold  or  mild!!!

Edited December 7, 2014 by tinybill

[Gibby]

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY SUNDAY DECEMBER 7TH 2014.

NEXT UPDATE MONDAY DECEMBER 8TH 08:00

THE CURRENT GENERAL SITUATION  A cold front will clear SE Britain this morning and a further showery trough crosses SE over England tonight followed by a cold NW flow ahead of a weak ridge of High pressure later tomorrow.

MODELS-2 WEEK HEADLINE Rather cold and windy for most with wintry showers or longer spells of rain or sleet with snow on hills especially in the North later this week. Perhaps milder especially in the South next week. Some night frosts where skies clear.

THE JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble forecast shows the flow positioned to the South of the UK with a trough in the flow to the East of the UK gradually lifting out in Week 2 to a flatter West to East pattern just to the South of the UK.

GFS OPERATIONAL The GFS operational this morning shows a lot of rather cold and unsettled weather across the UK as the pattern of Low to the North and occasionally NW and NE and High to the SW persists. There is spells of wet and windy weather shown for all at times followed by spells of colder and clearer weather with wintry showers across the North and West in particular. It is shown to be often windy too. Temperatures may recover towards average or a little above at times across the South for a time mid period.

THE GFS PARALLEL RUN The GFS Parallel run is not available until Monday of next week.

THE GFS CONTROL The GFS control run maintains a similar pattern to the operational with winds from a Westerly point alternating with more NW or even North winds at times as each weather system moves away East. Occasional rain followed by wintry showers will be a repeated process through the run with snow at times over most high ground.

THE GEFS ENSEMBLES  The GEFS Ensembles maintain a period of zonal Westerly winds over the next two weeks circulating around Low pressure to the North and High to the South. As a lot of colder air interjects at times especially across the North there will be wintry showery type weather for many of these areas too with frost and snow at times over even modest high ground on occasion. However, in the South these incursions will be shorter-lived and modified at times.

UKMO UKMO today shows deep Low pressure to the North and later NE of the UK with a progressively cold West then NNW flow for a time at the end of the run bringing plenty of rain showers in the South turning wintry over the hills next weekend while the North sees cold and windy conditions throughout with much more in the way of sleet and snow showers, appreciably over the hills.

THE FAX CHARTS The Fax Charts show a cold NW flow tomorrow give way to a strong Westerly flow across the UK from Tuesday. A front will bring milder winds for a time before cold air sinks slowly South  from midweek with snow and sleet showers in the North from midweek. A more organised band of rain crosses Southern Britain on Thursday before all areas experience cold and strong NW winds by the weekend with wintry showers.

GEM  GEM this morning also follows the pattern of strong Westerly winds and wintry showers developing later this week. these will be restricted to Northern areas in the frst half of the week with longer periods of rain crossing all areas on Tuesday and the South on Thursday before all areas become affected by a short injection of cold NNW winds and snow showers everywhere for a time. Late in the run winds back West and mild air sweeps East across all areas with some rain and a thaw in the North and West.

NAVGEM NAVGEM this morning could be written from the GEM textbook as it mirrors the sequence of events up to 18-hrs with a cold and changeable week giving way to milder conditions as we start next week.

ECM  ECM this morning shows a very changeable week to 10 days to come but shows less penetration of cold air into the South late this week that some of the other output shows. As a result quite a wintry week in the North with strong winds and snow showers look like lasting for three to four days while the South sees more moderate if rather cold conditions at times with rain on Tuesday and again on Thursday before showery weather occurs thereafter with a little wintriness only over the higher hills of the West. Then all areas see a backing of the flow towards the West resulting in all areas becoming milder and windy with rain at times but still with some incursion of colder and more showery weather across the far North at times.

ECM ENSEMBLES This morning's Ensemble data maintains the pattern of Low tpressure to the North and High near the Azores maintaining the changeable pattern of rain or showers at times across the UK with occasional shots of colder polar maritime air across the North of the UK sufficiently chilly enough to promote some wintry showers here while some frost is possible in quieter periods between fronts, again more common across the North.

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The main theme is for chilly Westerly winds to predominate across the UK veering to a colder still NW blow for a time later this week before flattening to a milder Westerly pattern next week.

MY THOUGHTS Some parts of Northern Britain are going to see quite a bit of wintry weather this week with plenty of snowfall mounting up on all the higher ground giving rise to some disruption with height. However, height asl is the key here as many lower lying areas will see only limited snowfall and little if any settling of the snow. In the South the pattern will be a lot less exciting with sunshine and showers giving way to more prolonged rainfall and for a time in mild air on Tuesday with more prolonged rainfall on Thursday too. It looks like the period of Friday to Sunday sees a window of opportunity for the South too to see some wintry showers while the North continue to see more troublesome snowfall over the hills. Thereafter the trend looks like the weather will become milder everywhere as the dig of cold into Europe is thwarted by rising pressure there forcing the Jet stream further North over Europe and tilting winds across the UK to a milder WSW orientation. Ther could still be some incursions of colder air into the North and West in particular at times with some wintry showers on the hills while the South will just see rain. Some frosts through this week are likely under clearing skies but there should be way to much wind for fog in a widespread form with frost too becoming more restrictive in week 2. In my opinion we continue to look to the North for the chance of a cold outbreak to occur between now and the New Year and although the shift in emphasis is looking towards less cold synoptics next week I think there will be further incursions of cold air coming down across the UK from the North or NW on various occasions between now and the New Year with little if any chance of anything cold arriving over the UK from mainland Europe within this period.

[carinthian]

Hey , come on. Not bad wintry charts for most in the reliable time span. Quite a few cold days and a risk of snow for some and it will feel bitter at times in the strong winds. Not major changes in the out -puts this morning. They will swop and change again in the all action week ahead. To put things in prospective, some parts of the south of England have already recorded more frosts than the whole of the horror winter 13/14 and its coldest day time temperature since the fridged March of 13 ! Not all doom and gloom this morning.

C

[fergieweather]

Gibby's analysis again broadly fitting UKMO overnight assessment. Noting caveat of 'significant uncertainties' even at the start of the 6-15d period & reflecting (as per my post last night) EC-ENS clusters, the Deputy Chief Forecaster concludes: "... uncertainties are likely to continue into the longer range, but anomalies of pressure and gph around the UK imply stronger than usual winds through the atmosphere and potentially stormy conditions continuing in the broadly W’ly flow." Colder phases with temps expected panning-out as average or slightly above.

[wolvesfan]

Morning all.

 

Its nice to see something more seasonal has arrived,Tomorrows chart indicative,

Cant say I'm too despondant going forward either.Hemisphericaly GFS in particular shows the heights which have been persistently low circa Baffin Island begin to drain and the residule energy eventually pushed to the Siberian sector.

Week three looks  good to me for potential although here on the ground we might have to suffer a while before we get what we want.

[nick sussex]

Hey , come on. Not bad wintry charts for most in the reliable time span. Quite a few cold days and a risk of snow for some and it will feel bitter at times in the strong winds. Not major changes in the out -puts this morning. They will swop and change again in the all action week ahead. To put things in prospective, some parts of the south of England have already recorded more frosts than the whole of the horror winter 13/14 and its coldest day time temperature since the fridged March of 13 ! Not all doom and gloom this morning.

C

Have you ever thought of  becoming one of my  helpline operatives? We're doing a recruitment drive and expect a big increase in demand.

 

We need people that can be positive in the face of adversity! lol Going back to the models in terms of the ECM ensembles.

 

http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim

 

The main clustering for De Bilt looks pretty average, theres still a few colder solutions which have survived this mornings carnage, overall though its looking uninspiring from a cold perspective after this weeks brief flirtation. A week can be a long time in the NWP and lets hope something more interesting shows up towards the Christmas period, I hope we can avoid a mild mush festive period.

[dbaloo]

good morning.mods please feel free to delete this post but as a novice here I really do enjoy reading the post by all members of net weather and I do learn something new every day about models etc.however the constant daily digs by certain members towards each other is firstly confusing for us less knowledge here and quite frankly its getting boring. We all have different weather preference and people don't post these days without a chart to support their view so why all the digs?anyway sorry for taking up space in the thread and keep up the good work every1!

[fergieweather]

Hi Nick - I can understand why using De Bilt as a meteogram / EPSGram site might have relevance to UK for assessing an incipient easterly/continental boundary layer-coming-to-us set-up, but not convinced it's best representative in broader sense...nevertheless it seems to be cited regularly on this forum, but I've never understood why? Cheers.

[Cloud 10]

The overnight ECM has thrown a spanner in the works at day 5 with a nasty little LP which it deepens markedly,which is in sharp contrast to the GFS.

 

ECM..  GFS..

 

Sets the alarm bells ringing when this sort of thing pops up in the near timeframe.

 

 

 

On another note,can we bring back the santa smilies,if only for nick sussex's sanity.

[Severe Siberian icy blast]

Hi Nick - I can understand why using De Bilt as a meteogram / EPSGram site might have relevance to UK for assessing an incipient easterly/continental boundary layer-coming-to-us set-up, but not convinced it's best representative in broader sense...nevertheless it seems to be cited regularly on this forum, but I've never understood why? Cheers.

Lol like you say Ian it's really because in winter time we chase the freeze, and generally it comes from the ease , so if there's signs of cold to our East , we can try our hardest to put a twist on it and give us yet another false hope of an easterly! A little bit more to it than that maybe but in all honesty that's the nuts and bolts of it I think !!

[nick sussex]

Hi Nick - I can understand why using De Bilt as a meteogram / EPSGram site might have relevance to UK for assessing an incipient easterly/continental boundary layer-coming-to-us set-up, but not convinced it's best representative in broader sense...nevertheless it seems to be cited regularly on this forum, but I've never understood why? Cheers.

If there was more data for the UK then I think you'd find that would take precedence however the ECM because of business concerns doesn't make alot freely available for the public which I of course understand.

 

Sometimes De Bilt can be good in terms of wind directions so for example a nw /n flow there is much more likely to translate to something similar for the UK, the problem of course can come with differing patterns with troughing near the UK but which brings in a south/sw flow over there which of course can be cooler because thats not coming off the sea, so yes I take on board your reservations but its a case really of just trying to make the best of the data available.

[IDO]

Hi Nick - I can understand why using De Bilt as a meteogram / EPSGram site might have relevance to UK for assessing an incipient easterly/continental boundary layer-coming-to-us set-up, but not convinced it's best representative in broader sense...nevertheless it seems to be cited regularly on this forum, but I've never understood why? Cheers.

 

I think for us Southerners it is useful as DeBilt (239 miles away) is closer to London than Scotland and on a similar latitude. Both have oceanic influences and the average temp difference is about 1c (less London) which is closer than the difference with Scotland. However the main reason is it is the nearest ECM meteogram us amateurs can get without paying for the ECMWF suite