General Model Output Discussion:

[Tom Montalbano]

Latest fax for t120, looking pretty similar to ECM at same time.

FAX. http://www.meteociel.fr/ukmo/fax/fax120s.gif

ECM. http://212.100.247.145/ecmimages/20100126/12/ecm500.120.png

Regards,

Tom.

[Snowyowl9]

Firstly the bad news rain for most/all when this comes through.

http://91.121.93.17/wz/pics/Rmgfs542.gif

Then the good news armaggddon comes. :lol:

Edited January 26, 2010 by Snowyowl9

[Cloud 10]

Latest fax for t120, looking pretty similar to ECM at same time.

FAX. http://www.meteociel...fax/fax120s.gif

ECM. http://212.100.247.1.../ecm500.120.png

Regards,

Tom.

Even without my usual snow spectacles on,that looks like a blizzard for scotland.

[WREXHAM]

IF (and that's a big if) the reality pans out the way the models are predicting then yes - the last cold spell will seem a slight small affair - but add these two together and you've got quite an amazing winter! - Only IF mind it comes off!

And what % chance do you think this will happen?:lol:

[PB22]

The coldest set of London ECM ensembles that I have seen from the 12z run:

http://www.meteogroup.co.uk/uk/home/weather/services/ensemble_forecast.html

Pretty consistent as well which is impressive!

[Bobby]

The coldest set of London ECM ensembles that I have seen from the 12z run:

http://www.meteogroup.co.uk/uk/home/weather/services/ensemble_forecast.html

Pretty consistent as well which is impressive!

ECM op not a huge outlier which is good.

[swilliam]

Apologises cold spell, but were the signs for that happening before it did similar in some respect.

They were similar in that they were shown in FI but the actual evolution here is quite different. Before Xmas it was a brief easterly into a Northerly but is shown here is the exact opposite and on a grander scale. It seems likely that we will get some very cold weather after the what looks like the very good Northerly this weekend. This can be gauged by the maor change in the ECMF ensembles which all now show cold solutions with almost none of the 50 showing temps above 0C in Holland for the next 15 days.

Also the GEFS ensemble mean is near or below -5 throughout although there is a wider spread (it will be interesting to see what the 18Z shows).

But the main issues are around the details and intensity of the cold - but as NS said earlier it is probably whether it is v. cold or bitterly cold. As for snow do not bother looking until 48 hrs beforehand.

[kold weather]

Synoptic evolution is very dodgy on the 18z, however it gets the job done as we still get a cut-off low. We have two ways to sustain cold therefore, either for the shortwave to be so weak it ends ups not coming into play at all (aka 12z GFS) or it cuts off and pressure rises in response, this is a slightly more risky evolution esp if the shortwave is stronger or other factors pop up, and it has to be said the most likely evolution from that would be a UK high, at least at first.

18z control runs shows exactly how it could very easily go wrong in that evolution however...

Very nice synoptics being progged BUT this is very far from a done deal, I'd still put very little faith into the predictions to be honest, and thats not being negative its just coming from what is a very 50-50 evolution...

[yamkin]

:lol: :lol: :lol: http://www.null/two/ensembles/ :lol:

[kold weather]

Looking through the ensembles, a real mixed bag there, some are quite amazing, others like the control run fail to get there because the upper high to our SW just gets stuck, eventual on the control run heights rise tothe north BUT the position of the low is terrible for the UK, still thats just one member of the ensemble of course.

The fact the ECM ensembles are decently cold is very good BUT then again they may well be suggesting a upper high stuck near the UK with a weak ESE airflow, or of course they may show the beast, probably a mixture of both I'd have thought in there, as well as some that go down the 18z control route.

IF we get into a cold evolution, then expect it to be every bit as long as the last one...and possibly without any mild interlude because the main block should be further SE then the first half of the last cold spell in December-Jan.

[john mac]

Wow what a day of model watching, plenty of excitement on here today, for me im just happy about the weather upto the weekend at the moment with plenty of wintryness about, after that the models are looking good but its too far away to expect too much ATM.

[TEITS]

Wow what a day of model watching, plenty of excitement on here today,

I feel worn out already.

One of the most exciting charts today is actually the +120 fax chart especially if you live in Scotland, particularly the NE.

Overall an excellent day of model watching which hopefully will continue tomorrow.

[stewfox]

Very poor run for FI - we only get to this!

9th Feb my birthday ! A repeat of 9th Feb 1986 me thinks

[Duane S.]

Don't you just love it when you spend half an hour typing something late at night to lose it all. Grrrrrr

Not a time to be angry though because basically what I had typed earlier was that this afternoons/evenings charts, the ECM in particular, were just incredible. I'm not sure anyone could draw better synoptics than the ECM latter stages baring in mind we are talking the UK here.

I was talking about an impending Northerly and then later a possible Easterly over a week ago but I never imagined I would see this and certainly not so quickly. Is it all too quick?, too progessive though?? What I had envisaged was a menadering HP cell sat to our West for at least another week to 10 days, with energy to our NW restricting any sort of retrogression. I still find it incredible (if the models are to be believed) the relatively little effect the recent sustained cooling of the stratosphere has had on the Polar Vortex though.

Tropical convection contiunes to drive the MJO towards favourable phases, the mixed ensembles forecasts are incredibly bullish...

The AO now looks once more in 'tank mode'

The latest ensembles for 'the tropics' are extremely encouraging...

AND last but not least, this (what a chart)...

Human nature and experience urges me to curtail my excitement for now but with signals and synoptics like these on offer its not easy!

[Lewis]

9th Feb my birthday ! A repeat of 9th Feb 1986 me thinks

My Birthday (Hoping for an upgrade) LOL

[SMU]

Downstream favourable 500mb Heights promote Easterly for NW europe in the 150-200 timeframe- however will upstream signal play ball????

GFS to fast & Southeast on American System means the evolution for the midterm of 150-180 is to far South & East for NW europe-

ECM looks to resolve the energy better & pulls shortwave energy further North towards the coast- meaning the evolution is a long way further NW over Europe-

What am I talking about I hear you ask???????

The fate of our Easterly ( The Easterly reload after the Northerly) is being driven by energy from the Subtropical jet all the way back the SW portion of the US-

Energy arriving in the SW portion of the US under the ridge at T72 Alligns with a Very cold parcel of artic air pushing south out of canada at the same time, the convergence zone will see a shortwave develop-

http://wxmaps.org/pix/hemi5.72hr.png - See the jet energy coming into the SW of the US & the northern energy moving directly South through the central Plains ( strong + PNA pattern )

See the Shortwave develop at 72 ish-

http://91.121.94.83/modeles/gfs/run/gfsnh-0-84.png?18

The model bias of the GFS generally pushes southern Stream energy to far out & to fast/to far east in the 72 + 96 timeframes ( subsequent runs SHOULD pull it back west & North)- Obviously after which along the 120 + 144 timeframe if the track is ejected into the atlantic at a point a long way further SE then the subsequent atlantic ridging that is building Northwards will be forced in a NE Direction at a lower Latitude-

Hence the GFS arriving at a ridge over the UK at around T 180-also at this stage so is the ensemble mean- notice how the ensemble 850 profiles are dropping back now over the last 24 hours - this is a result if the gfs beginning the see & resolve the pacific energy & speed at 72 + 96

If its resolving the energy wrong over the states though & the energy is tighter & generating more of a ridge ahread of it then its track will carve a more Northward path up through the SE part of the states & exit say the Central / Eastern part of the coast rather than the SE- this track then dictates that the ridging in the Atlantic can be more alligned South North & at more of a North Westerly locale-

If the jet energy is more orientated towards South North across to Western Greenland then the it will have a sharp gradient coming back North South through iceland - the resulting pattern is that the ridge can migrate towards Iceland then fill the void of low heights to heigher heights in the Svalbard region-

This is at a TIMELY point in this current winter to see such a devlopment in terms of pattern retrogression because the zonal wind anomaly & 50/60N observations are dropping almost into negative territory- meaning that any shortwave system traversing lattitudes across 35N to 60N in the atlantic will have less EASTERLY force acting on them- so the recurve that usually happens when we get close to the GIN coridoor will be less prominent & SHOULD allow for ridging to extend further North than usual, because the downstream flow is also convoluted then this has every chance for allowing a pattern to develop that backs the cold westwards ALL the way to the UK, as opposed to just holding it to our east-

The next 5 days & pattern development will make or break our Febuary CET- if that shortwave over the states holds up slower & further north at T90 odd ( compare run V run in terms of location) then the chance of a below 1c 1st-14th CET is high, if it does eject faster which I think is unlikely ( & the 18z GFS is wrong) then we could be quids in-

Probability of an Easterly Outbreak in 8-10 days ~ 70%

Steve

[aien aristeuein]

I am new at this game so please put up with my novice talk.

Well based on this mornings output prior to the ECM being posted I sense we may be in for a morning of nail biting as the GFS at 126 to 180 could go either way albeit it freezes the proverbials in la-la land. The UKMO is also set to raise the tension levels at 120 to 140. One reason I joined the forum was situations like the one ahead of us are so truely fascinating. Perhaps it will lead to epic cold, perhaps not but certainly makes for an exciting ride.

AA

[Iceberg]

The 00Z show exactly what Steve was on about above, the energy leave the US is probably notable different and further east.

The good news is that this doesn't really effect the end game happenings 8 days down the line, except in the case of the ECM which takes the Jet over rather than under the high.

It just doesn't produce the magic 12 hrs after the northerly has gone.

The 00Z longer range is incredibly similar to the 12Z from GFS yesterday.

For me the best news is looking at the 12Z ECM ensembles for London. The maximum average from next week is 3C, there was a dramatic shift in the Ensemble spread and mean on not just GFS but Also ECM, this is worth 3 or 4 incredible ops runs for me.

Anyway back to this morning.

ALL 3 models take a more easterly axis from the states, flattening the high, however there is still no real Jet to prevent the Sib high from moving westwards into Scandy (and the eventual Greendland join up) on the GFS. ECM is another matter.

So all very good charts except for the ECM which just adds a little too much energy into the northern arm.

Some decent precip from the upcoming northerly over the weekend as well and into Monday. Friday is still marginal due to the small low pressure development and I still think the wrong side of marginal for most to have lieing snow.

There might be a few people saying it's all over looking at the ECM however the ensembles don't agree, with the Jet angle as is, it would be unlikely for that much energy to go above the block IMO and even then it cant sustain it at 240T

[SteveB]

Love GFS FI, just on the verge of getting some truly epic cold (-20 850's) & it gets stopped in it's tracks with a northerly & -10c 850's. Hey ho beggers can't be choosers

[bluearmy]

iceberg said it so i wont bother - look at ther ens. less progressive is nearly always right, be it mild or cold. of course, the shotrwave out of the gulf may well run nearer the coast on the 12's again so you never know ............................

[aien aristeuein]

Just wanted to add having seen the ECM output now

Seems as though as much as there was stunning agreement from the GFS, UKMO and ECM las night on the freeze to end all freezes, this morning the is stunning agreement in the critical 120 to 180 timeframe from the same models to be very circumspect on cold from the east. Looks as though we will have to sit and see how things develop. I saw SM's overnight post which highlighted some difficulties out of the US in modelling the outcomes on our side of the pond.

AA

[Frosty.]

In the short term, the Northerly is now being delayed by 24 hours with the proper Arctic flow not arriving until during friday but then continuing through the weekend plus next monday as the scandi trough edges westwards and then fills early next week. It's fairly obvious the GFS 00z shows the best evolution to continued cold beyond monday but the ecm 00z falls apart in FI and the ukmo 00z @ T+144 suggests to me the cold snap on it's last legs.

[cooling climate]

I would take what the Euro models are showing this morning as just a wobble and are

wrongly modeling what happens if a piece energy lifts out of Scandinavia and the effects

this will have.

Another juicy, juicy run from the 0z GFS this morning which surprisingly has not been led

up the garden path by this small change. Mind you on the 18z last night it showed a

similar evolution to what the Euro's are now showing but has now corrected.

The outlook remains very very cold and wintry.

[cyclonic happiness]

The gfs is looking exellent but the ECM is looking a bit chaotic and jagged like there's too much detail for that far out??

Meto is 'meh'.

But all in all, still looking good for a nice white splodge before spring

[MR EXTREMES]

i dont really know what to make of this fax chart very disturbed stuff coming out of nfl with the alantic ridge drifting south surely this is not good sign for future development of a easterly i hope im wrong though.