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Paul

Model Output Discussion - The Start Of Winter

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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

post-12275-0-17906700-1417933802_thumb.p

post-12275-0-32517400-1417933810_thumb.p

post-12275-0-05146300-1417933819_thumb.p

Edited by Polar Maritime
To remove reaction comment.

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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.

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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

post-12275-0-58729000-1417936800_thumb.p

post-12275-0-24566800-1417936807_thumb.p

Edited by Polar Maritime
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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 by Polar Maritime
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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:

 

post-14819-0-94815100-1417937671_thumb.g  post-14819-0-13345700-1417937684_thumb.g

 

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

 

post-14819-0-79237400-1417937775_thumb.g

 

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:

 

post-14819-0-93267900-1417937925_thumb.p  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: 

 

post-14819-0-07832200-1417938066_thumb.p Support op & C: post-14819-0-69427800-1417938881_thumb.p post-14819-0-41586700-1417938810_thumb.p

 

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: 

 

post-14819-0-52015300-1417938216_thumb.p

 

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: post-14819-0-51079700-1417938996_thumb.p mean next weekend: post-14819-0-44520500-1417938547_thumb.p

 

London ensembles post-14819-0-56121500-1417938558_thumb.g

 

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

Edited by i'm dreaming of...

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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 by Polar Maritime
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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!

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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 by Polar Maritime
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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 by Polar Maritime

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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 by Polar Maritime
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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.

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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.

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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 by tinybill

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Morning all.

 

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

h850t850eu.png

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.

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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.

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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.

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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. :laugh:

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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 !!

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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.

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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 :)

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