General Model Output Discussion

[Jezzer]

People would still be talking about downgrades.......

fascinating charts though, never seen this before. cold snowy christmas is my take on this.

Looks like a lovely and cold Christmas Eve

[John Snow]

I said the other day that the cold would last till right through to April with reload after reload hammering the nation with snow from the East and the North with no real mild spell all winter and was laughed at, but now it is looking more and more like a reality

[Frosty.]

Yes i agree apart from add west midlands and particularly NW midlands as being in with a chance of snow showers too, told you the cold spell would come off frosty i know you had your doubts after that ECM 00Z run earlier this week

Nice GFS 06Z around christmas weekend BUT i would like GFS 12Z to continue the trend as GFS 06Z along with 18Z we all know can be quite wonky at times

hi Eugene,

LOL you won't let me forget that ecm run will you

The models are fascinating at the moment, it could go either way but the signs are good that it will at least be cold even by christmas day and possibly beyond, a very complex pattern with lows changing position every run, encouraging gfs 06z but I would really like the ukmo and ecm to look a bit better, hopefully the 12z will clarify things more.

Get the train?

wrong kind of snow?

[stewfox]

make sure you take a look at the T120 FAX from yesterday before it goes this evening. Thats a very rare sypnotic chart. Doubtful if anything like that has ever been issued on the internet.

anyone care to place a wager on a breakdown ???

Post a link ?

[wellington boot]

I know this might be considered of topic but i wanted the more experienced on here to answered and everyone reads this thread. If we take the GFS 06z and ECM outputs would you say the LOW moving down from the north this weekend will give a high ammount of snow fall for the NW region and Scotland??

There also doesnt seem to be much talk of this low on here too. I realise that the SE has had a pasting but it seems everyone is now looking to the SW for the mild weather to come in/ or not and ignoring this very good potential for the north.

Don't worry the cold front coming from the north saturday night has everybody's name on it, especially the NW and Scotland. But it's a relative certainty, so not so interesting to discuss! Maybe 5-10cm out of that.

[Bolton67]

Post a link ?

http://www.wetterzen...pics/brack4.gif

[joespontiac]

Post a link ?

http://www.wzkarten.de/pics/brack4.gif

[Michael Fishermans Friend]

That will bring rain to the south I reckon, maybe snow on the chilterns - still a very mixed and messy synopsis though.

[Rob K]

That will bring rain to the south I reckon, maybe snow on the chilterns - still a very mixed and messy synopsis though.

Yes - that fax chart is remarkable not really for the temperatures or weather it will produce as for the synoptics - a perfect semicircle of high pressure centres across the top with lows trapped below. Flip it upside down and you'd have a more usual winter chart!

[cooling climate]

Strange response from the NCEP this morning regarding the synoptics upstream in the t144-168 time frame.

PRELIMINARY EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

505 AM EST FRI DEC 18 2009

VALID 12Z TUE DEC 22 2009 - 12Z FRI DEC 25 2009

DID NOT TRUST THE TREND ON THE 00Z/18 ECMWF TOWARD A DEEP CYCLONE

OVER THE GREAT LAKES BY DAY 7... DESPITE THE SUPPORT FROM THE GFS

AND GEM GLOBAL. THE UKMET KEEPS THIS ENERGY ENERGY SUPPRESSED BY

A DOMINANT NORTHERN STREAM...AS DID THE LAST SEVERAL EC ENSEMBLE

MEANS AND PRIOR DETERMINISTIC RUNS. THE STRONG BLOCK HELD IN

PLACE BY THE NEGATIVE NAO SHOULD PRECLUDE MAJOR CYCLOGENESIS IN

THE GREAT LAKES REGION FOR SOME TIME TO COME...UNLESS THERE IS A

COMPLETE DESTABILIZATION OF THE PATTERN. USED A BLEND OF THE

12Z/17 ECMWF AND 00Z/17 EC ENSEMBLE MEAN...WITH THE 12Z/17 MEAN

FILES INCOMPLETE AND THE 00Z/18 MEAN DATA NOT AVAILABLE IN TIME

FOR THIS FORECAST. THIS MANUAL BLEND BRINGS ANOTHER WAVE FROM THE

GULF STATES TO CAPE HATTERAS AT THE END OF THE PERIOD...WITH MORE

SNOW FOR THE APPALACHIANS AND MID ATLANTIC STATES BY CHRISTMAS.

Sounds to me as though the GFS and ECM operationals have been thrown out and that they are

giving full support to the UKMO.

[Iceberg]

I don't know whether this link has been made available here, but here are the ECMWF ensembles for London, along with a super ensemble showing the GFS run.

It shows that Cold is just as likely after christmas as any warmup.

Enjoy it while you can as this breeches ECMWF guidance on chart distribution and so probably won't last long !.

It also has detailed 850's out to 240.

http://www.meteogroup.co.uk/uk/home/weather/latest_model_forecasts/ecmwf/archiv/NSea/thgt850/2009121800/nothumb/ch/99e4ff482f.html

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

[Nath]

http://www.wetterzen...pics/brack4.gif

That chart is so close to prefection, 100 miles shift for a snowfest!!!

[Duane S.]

Back in early November teleconnections genius GP told us that we were about to embark on very wet and unsettled period. He also said that the atmosphere had yet to be engaged by the Nino and that the Nina like conditions were going to build up a lot of cold air up in the Arctic ready for release in December. Yet again, hugely impressive.

As for where we are right now, I see that the GWO is well placed to go into into phase 5 later on, plus now the MJO seems to be taking a decisive route towards phase 7 . All good news for January I reckon as does this not indicate a strong -NAO signal amongst other things?

Also could somebody in the know confirm that I am reading this right, that the bullish GWO indicates that the NINO is starting to connect???

[Glacier Point]

Back in early November teleconnections genius GP told us that we were about to embark on very wet and unsettled period. He also said that the atmosphere had yet to be engaged by the Nino and that the Nina like conditions were going to build up a lot of cold air up in the Arctic ready for release in December. Yet again, hugely impressive.

As for where we are right now, I see that the GWO is well placed to go into into phase 5 later on, plus now the MJO seems to be taking a decisive route towards phase 7 . All good news for January I reckon as does this not indicate a strong -NAO signal amongst other things?

Also could somebody in the know confirm that I am reading this right, that the bullish GWO indicates that the NINO is starting to connect???

Correct. You can chart this in terms of snowcover, falling during late November and early December before rapidly recovering of late.

http://moe.met.fsu.edu/snow/

This would appear to be manifested in a particularly in a strong sub-tropical jet and there is a really strong fetch of westerlies across the Pacific right now.

Sit back and wait for the wavelength changes to work their magic.

Meantime, long range ensemble tools suggest upper lows to penetrate past the Meridian forcing height rises towards Svalbard and preserve the ridge over Greenland:

http://raleighwx.eas...htAnomalyNH.gif

http://raleighwx.eas...htAnomalyNH.gif

Edited December 18, 2009 by Glacier Point

[Mark Bayley]

Correct.

This would appear to be manifested in a particularly in a strong sub-tropical jet and there is a really strong fetch of westerlies across the Pacific right now.

Sit back and wait for the wavelength changes to work their magic.

Meantime, long range ensemble tools suggest upper lows to penetrate past the Meridian forcing height rises towards Svalbard and preserve the ridge over Greenland:

http://raleighwx.eas...htAnomalyNH.gif

http://raleighwx.eas...htAnomalyNH.gif

Hopefully the next spell will be able to bring me more than a dusting There is still Saturday night though... I have been reading your updates in the technical thread! Some great posts

GFS ensembles show the 850hpa temp never getting above 0c! (just about does it on the 2nd of Jan :lol: ) Seems very good agreement on the ensembles for a cold Christmas day, so white Christmas for at least the midlands north in terms of snow already lying on the ground, that's if it doesn't melt... Of course there is still uncertainty, however signs do look promising from the GFS. Not seen the ECM, UKMO yet, however i noticed from a few posts its on the top end of the ECM ensembles.

GFS ensembles: Derbyshire

[Frosty.]

Meantime, long range ensemble tools suggest upper lows to penetrate past the Meridian forcing height rises towards Svalbard and preserve the ridge over Greenland:

Hi GP,

Does that mean it might stay cold in the north throughout? with less cold incursions struggling to penetrate much into the uk..It looks messy next week and the meto are very unsure how long this cold spell will last, especially in more northern regions, could it last until the new year before a reload for the whole uk?

Edited December 18, 2009 by Frosty039

[Optimus Prime]

Looks like as we ehad towards Christmas our friend from the east is starting to make an appearance.

[Upgrade]

is it a case of "the models are struggling = breakdown on the way" or is it genuinely unknown. Interesting to note that on the 1330 weather, Darren Bett was ramping up the northerly blast and the cold weather yet to come.

[SNOW-MAN2006]

is it a case of "the models are struggling = breakdown on the way" or is it genuinely unknown. Interesting to note that on the 1330 weather, Darren Bett was ramping up the northerly blast and the cold weather yet to come.

Similar to the old man that did th eweather last night, cant remember his name but he always talks sooooo slow but he talked about the weekend then went "ahhh and then theres monday to come" in a rather evil manner to finish off his forecast.... :/ lol

And why is it so quite on here recently, every one out building snowmen, this topic has gone from a post a minute to a post an hour in the space of 2 days !

[NorthNorfolkWeather]

This would appear to be manifested in a particularly in a strong sub-tropical jet and there is a really strong fetch of westerlies across the Pacific right now.

Sit back and wait for the wavelength changes to work their magic.

Hi GP,

Thanks, informative as usual. A couple of questions if I may

Where does the information on the sub tropical Jet and teh Westerlies in the Pacific come from?

What length of time do you expect these wavelength changes to take? Are we talking a couple of weeks? Or more like 4-6 weeks?

[cooling climate]

My punt would be that northerly blocking will prove to be stronger than is currently being modeled

and we will see the models continue to backtrack on any milder or less cold weather to affect the

UK.

We could even be looking at a reload of the cold in another 5-7 days with pressure rises to the n/east

and undercutting lows.

[NorthNorfolkWeather]

Similar to the old man that did th eweather last night, cant remember his name but he always talks sooooo slow but he talked about the weekend then went "ahhh and then theres monday to come" in a rather evil manner to finish off his forecast.... :/ lol

And why is it so quite on here recently, every one out building snowmen, this topic has gone from a post a minute to a post an hour in the space of 2 days !

Blooming Youngster!! that was Rob McElwee, Suddenly all the BBC weathermen are converts to Cold.

Back on topic,

It still looks, to me, that there will be a mixing of some mild air with the cold for the South, but the models seem somewhat 'Confused' beyond 60-72 hours. so FI starts at 2.5 days

[kold weather]

Correct. You can chart this in terms of snowcover, falling during late November and early December before rapidly recovering of late.

http://moe.met.fsu.edu/snow/

This would appear to be manifested in a particularly in a strong sub-tropical jet and there is a really strong fetch of westerlies across the Pacific right now.

Sit back and wait for the wavelength changes to work their magic.

Meantime, long range ensemble tools suggest upper lows to penetrate past the Meridian forcing height rises towards Svalbard and preserve the ridge over Greenland:

http://raleighwx.eas...htAnomalyNH.gif

http://raleighwx.eas...htAnomalyNH.gif

I think we are seeing that on the models this morning, you can see both the ECM and the GFS keep heights decent over Greenland. However the differences between the synoptics of the GFs and the ECM are pretty big to be honest and so there are other situaitons that need to be resolved first, but the fact that there looks like there could be a ridge over Greenland still present is a good sign.

My main concern is with regards to the low pressure that comes up from the south, if it decides to swing round and exit too far west then the door will be open to a much milder set-up just after xmas...though even in that set-up Scotland would never be far away from the cold with the ridge possibly in place...

[Jezzer]

I did wonder what Rob McElwee was hinting at for Monday, that cheeky laugh and talk about Monday's weather even had Radio One chatting, I presumed Rob was hinting at widespread freezing temps and snow

Edited December 18, 2009 by Jezzer

[Upgrade]

I did wonder what Rob McElwee was hinting at for Monday, that cheeky laugh and chaty about Monday's weather even had Radio One chatting, I presumed Rob was hinting at widespread freezing temps and snow

maybe he was just referring to the BBC weather office christmas party.