Model Output - General Discussion

[Spurry]

A much better run for my area, out to 168hrs at the moment and looking good

[benb]

Worth noting western windward coasts may do exceptionally well (for snow) if this set up comes to fruition.

[ISAAC]

the 12z seems to be rather progressive and quite snowy or the midlands from early as wednesday...

That is just about within +72 so definatly noteworthy, lets see what UKMO and the Euros say about this one.

Next 24 hours of model watching are going to be very very interesting, i would be very surprised if the MetO failt to put up a weather watch by tommorow if this trend continues.

PS: the polar low forming at +144 .

[Snowmad79]

I'd have to agree that 12z is by far an improvment on the morning GFS runs. At T144 the North West comes into the fray with the potential for a really good dumping !. The Lp to our north sinks faster and the HP looses enough of a grip on the west to unleash the White stuff on us . Generally a good run up to now for sure.

Being on the planet 30 years my expectations are high and last Feb came close to the likes of winter wonderlands of pre 96-97 winters with snow lying for 5 to 6 days 2ft drifts and up to 6 ft in places. Could this top that ?

[Neilsouth]

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=72&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=96&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=120&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=9144&carte=1021

Ukmo lessens the easterly aswell , though now we are looking to the north for snow?. Next it will be the west , sigh

[Snowaddict]

http://www.meteociel...h=72&carte=1021

http://www.meteociel...h=96&carte=1021

http://www.meteociel...=120&carte=1021

http://www.meteociel...9144&carte=1021

Ukmo lessens the easterly aswell , though now we are looking to the north for snow?. Next it will be the west , sigh

UKMO is still a VERY good run in terms of the easterly, albeit only slightly less prolonged & potent than this morning, especially @ T+144..

I thought that this was going to be a balanced thread?

There is still plenty of scope for easterly snowfall from the UKMO along with snow spreading south towards T+144..

Honestly, if people are not happy with these outputs then I don't know what to say!

[Eugene]

GME 12Z has a very cold easterly heading our way, looks a very strong stable cold spell too with no end in sight

http://www.wetterzentrale.de/pics/Rgme1321.gif

http://www.wetterzentrale.de/pics/Rgme1322.gif

UKMO 12Z is a great run neilsouth stop the melodrama for gods sake.

[snowking]

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=72&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=96&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=120&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=9144&carte=1021

Ukmo lessens the easterly aswell , though now we are looking to the north for snow?. Next it will be the west , sigh

This baffles me no end I must say....I think perhaps some people need to revise their techniques for viewing the charts, and take a look back at some of the synoptics we've had in the last 20 years or so, then come back and say that isnt a decent eaterly

No wonder some of the less experienced among us are utterly confused by whats going on at the moment when theres some false information flying about

[TEITS]

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=72&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=96&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=120&carte=1021

http://www.meteociel.fr/modeles/ukmo2.php?nh=&ech=9144&carte=1021

Ukmo lessens the easterly aswell , though now we are looking to the north for snow?. Next it will be the west , sigh

I disagree as there is a good 36hrs of potential.

The only reason the 12Z +144 doesn't look as good as this mornings is because its now 12hrs later! Even the +144 chart would bring snow showers into E Anglia.

[kold weather]

Not really by much though, UKMO still has a pretty pokey looking easterly at 120hrs, I'm pretty sure we'd get some snow from that sort of airflow. Not ultra cold but it'll do I'd have imagined.

[Nick L]

http://www.meteociel...h=72&carte=1021

http://www.meteociel...h=96&carte=1021

http://www.meteociel...=120&carte=1021

http://www.meteociel...9144&carte=1021

Ukmo lessens the easterly aswell , though now we are looking to the north for snow?. Next it will be the west , sigh

What a daft post. Those charts are fantastic. Belting easterly followed by a promising northerly. Please don't drag this thread down to the depths it went to last night.

[Tom D]

GFS parallel is very similar to the operational, only without the polar low which appears at +144 in the latter.

http://91.121.94.83/modeles/gfsp/run/gfs-0-144.png?12

Although the two low system does eventually form at +168.

http://91.121.94.83/modeles/gfsp/run/gfs-0-168.png?12

Edited December 13, 2009 by Tommyd1258

[Iceberg]

UKMETO is fantastic for everybody, even some sub 500 air in that approaching northerly.

[winter watcher]

I posted last night with my thoughts from inside info from a good friend and exactly what he said so far has come true. I am not to sure as off why a few was slating the ECM this morning and favouring the GFS. The ECM sorted the flip episode 3 days ago and has remained constant ever since while the GFS up until three days ago was consistent they both swapped places by the looks off things i did get information passed on to me saying the GFS will come in line by possibly tonight's pub run if not tomorrow and looking at the two GFS runs today they seem to be edging closer and closer with the ECM. Plenty to be ecstatic over i know i am.

[Grimsby Snow Lover]

This baffles me no end I must say....I think perhaps some people need to revise their techniques for viewing the charts, and take a look back at some of the synoptics we've had in the last 20 years or so, then come back and say that isnt a decent eaterly

No wonder some of the less experienced among us are utterly confused by whats going on at the moment when theres some false information flying about

Thankyou for stating that Snowking, I am well confussed at the moment and don't know what to think. Are we not heading for a cold spell that might deliver a bit of snow? Looking at the last few charts I would say that eastern areas aswell as northern areas should at least see a bit of snow. The 528 dam line is well passed the bulk of the country - is this a good sign?

[Iceberg]

Longer term I am thinking more and more of a potential 4 day milder spell and then a very potent easterly between christmas and newyear.

The 12Z GFS is too progressive with the LPs in the northerly(not polar lows) and so the quick pulling in of mild air is probably over done as well.

[Harsh Climate]

This baffles me no end I must say....I think perhaps some people need to revise their techniques for viewing the charts, and take a look back at some of the synoptics we've had in the last 20 years or so, then come back and say that isnt a decent eaterly

No wonder some of the less experienced among us are utterly confused by whats going on at the moment when theres some false information flying about

Its not false information its just his oppinion. Im not suprised the less experienced members are confused as it IS very confuzing. It would be wrong to mislead all these people into thinking it was brilliant with bags of snow on the way as that just isnt the case.. Were on a knife edge situation, of which we need the ecm/ukmo to stay firm later and for the gfs to join ship very soon!

otherwise we may be looking at an ordinary cold spell with a bit of patchy snow in places before milder conditions eventually moving in, which is a far cry from the monumental potential the charts have showed over the last few days..

It seems to me like any one who isnt quite sucked into this and mentions anything to do with mild gets slated and anyone who mentions extreme cold/snow is treated as a hero.. people must move away from this logic if were guna have decent discussions/debates..

Edited December 13, 2009 by Jed Bickerdike

[snowking]

Thankyou for stating that Snowking, I am well confussed at the moment and don't know what to think. Are we not heading for a cold spell that might deliver a bit of snow? Looking at the last few charts I would say that eastern areas aswell as northern areas should at least see a bit of snow. The 528 dam line is well passed the bulk of the country - is this a good sign?

This is very much a good sign. It might be worth nearer the time taking a look at the 'Will It Snow' section on the forum and taking a look at the factors involved, but generally from this run the thicknesses and the 850mB temperatures are cold enough for snow, and as today has shown we will get some impressive convective activity to create the precipitation.

From a longer range the key things to watch in the models are definitely the thicknesses (so sub 528DAM) and the 850mB temps (lower than -5c is generally accepted as the potential snow line)

Then as we get within 48-36 hours we start to look at temperatures, dew points etc.

For now i'd stick with some of the analysis from the likes of Steve Murr, Kold Weather, TEITS, Nick Sussex and Paul B who really know what theyre talking about in terms of the models, and definitely dont get wound in by some of the jokers around here currently!

All eyes on the ECMWF now with the FAX's out later this evening

SK

[SMU]

I disagree as there is a good 36hrs of potential.

The only reason the 12Z +144 doesn't look as good as this mornings is because its now 12hrs later! Even the +144 chart would bring snow showers into E Anglia.

Yes-- this ^^^

Ive maintained that an easterly incursion would at best deliver 24-36 hours of snow potential in terms of convective Showers-

if you look at the 12z UKMO then the snowfall starts I guess around T100 /110 & runs to around T132/138-( BTW thickness over london at 120 is around 515 dam-)

The CRUCIAL element on the UKMO isnt the Easterly but the positioning of the 3 troughs-

* Scandi trough means that even if we get a breakaway shortwave spinning off to the West then it wont get west of the meridian-

* French trough- again EAST of the Meridian keeps a decent NE flow going at 144- means more snow flurries in the East-

* Atlantic trough propping up the block-

S

[TEITS]

I want to clear up the end of the week as there seems to some confusion, especially with regards to expectations.

Now we all know this E,ly won't lost long but the question mark is how cold, flow, duration. I shall use the 12Z UKMO as an example.

At +96 we have a ESE,ly flow bringing in colder air from the continent. Now a ESE,ly won't produce much snowfall for the SE but snow showers are possible from E Anglia northwards.

At +120 the flow has changed to an E,ly and the combination of a brisk bitter E,ly wind moving across the N Sea would bring heavy snow showers for the SE/ E Anglia/Lincs/Humber.

At +144 the snow showers would be fading away although some would remain in E Anglia at first.

However if you compare to the GFS Parallel run you will see the GFS is far more progressive.

http://91.121.94.83/modeles/gfsp/run/gfs-0-120.png?12

P.S If the UKMO verified the snow showers at +120 would penetrate well inland.

[Cecil Hogmanay Melchett]

UKMO is Cold Eastrly followed by an Artic Northerly.

OMG what a run.

PV dropping into Scandanvia at t+144 and a great big Greenland high.

Am i dreaming ?

[snowking]

Its not false information its just his oppinion. Im not suprised the less experienced members are confused as it IS very confuzing. It would be wrong to mislead all these people into thinking it was brilliant with bags of snow on the way as that just isnt the case.. Were on a knife edge situation, of which we need the ecm/ukmo to stay firm later and for the gfs to join ship very soon!

otherwise we may be looking at an ordinary cold spell with a bit of patchy snow in places before milder conditions eventually moving in, which is a far cry from the monumental potential the charts have showed over the last few days..

It seems to me like any one who isnt quite sucked into this and mentions anything to do with mild gets slated and anyone who mentions extreme cold/snow is treated as a hero.. people must move away from this logic if were guna have decent discussions/debates..

Hi Jed,

I take your point completely, but all we can go by is the facts given to us from the NWP output at the moment. And that output is generally conductive of snowfall for a large part of the UK, with sub 528 DAM and -5c 850's widely (colder the further east you head) being predicted.

There is every chance that something such as Dews, Temps etc may not play ball but we wont know that until nearer the time (along with potential warm sectors). However at present some of the gloom on here is simply not justified. Everybody is of course entitled to an opinion however you need something to back that opinion up....presently I just see no evidence to back up a claim of this easterly suddenly being awful!

Kind Regards

SK

[cold snap]

Would i be right in saying on tonights outputs.

We look to the North first.East Second.North third?

[Geordiesnow]

Decent enough UKMO regarding the easterly so that's good news to say the least, not sure how cold it will be mind but probably on the right side of marginal i would imagine.

GFS has decent potential regarding the Northerly but position and all that will change and until we know what happens with this easterly then i'm not really going to focus too much onto it.

Again though, very little sign of any mild weather and once the cold is over us, it can stick around for a while.

[nick sussex]

The gfs still looks like its not going with the euros, that aside the ukmo if you're looking for a sustained colder spell is excellent, any low that heads south from the north is likely to interact with low pressure to the south of the uk , in the ukmo shown over the med, because of this we dont want the low heading south too far west, this happens with the gfs and could lead to a complex feature eventually pushing a milder flow in from the south.

Lets hope the ecm sides with the ukmo here, in these situations theres low margin for error, you want the Scandi trough close to the east but not sitting over the uk.

The gem backs the ukmo at 144hrs, heres the gfs and gem viewed all the way upstream to the USA also see how much further west the low is on the gfs.

GFS

http://moe.met.fsu.edu/cgi-bin/gfstc2.cgi?time=2009121312&field=Sea+Level+Pressure&hour=144hr

GEM

http://moe.met.fsu.edu/cgi-bin/cmctc2.cgi?time=2009121312&field=Sea+Level+Pressure&hour=144hr

Start praying that the ecm sides with the ukmo and gem, we want the gfs to be completely wrong here.

Edited December 13, 2009 by nick sussex