Winter Model Discussion 12Z 09/01/13> The hunt for cold ?

[stainesbloke]

Its because the GFS has a lot of data with the west in mind. It NEVER! handles easterlies well.

With that said, It shouldnt be discounted. What it shows is very much possible. However with a strong eastern influence the chances are that any LP's or shortwaves will be greatly overdone in the model almost up to 36 hours out.

I would take what the GFS says seriously but would remove a bit of strength from the west.

No, the GFS shouldn't be discounted, look what happened in Dec.Many were saying the GFS always overcooks lows/is overly aggressive with the Atlantic etc etc....and thats exactly what happened. Background signals this time are different though which gives me some hope of a greater chance of cold.

[Paul White.]

Wow that gfs 12z run was completely different to yesterday. How can you have confidence in its output? Previous to today's 00z output it had 4 in a. row showing GL blocks and now 3 in a row showing GL low heights for next week. Before anyone says the gfs leads the way and ECM will have to fall in line I say "fiddle sticks " I think what happens is the gfs runs 4 times a day and goes out further than the other models. Which gives it a chance of finding somthing in FI what I am trying to say is if the ECM follows the gfs then we will be under a GLH next week but if the ECM follows today's output from the gfs then none of the models are to be trusted post d6-7 talk about model uncertainty.

Paul

[bradymk]

GEM digs in the upper trough a bit later than 00z run, but end result at 168 will be about similar- another run that takes the UKMO, EC line of thinking instead

Yes shame it only goes to 144 on the 12z run, still a good run the GEM, not following GFS thats for sure so another positive. We now await the ECM

[Alexis]

My take would be that this is because one person is looking at Monday/Tuesday where indeed the 12z GFS Is a big improvement on the 06z. But the second person is moving onto Weds next week and it's back to westerly zonal weather on the 12z GFS, whereas the European models are suggesting (along with the constant anomaly charts that don't swing wildly like every run) that mid week next week will be a blocked pattern with continuing cold across the UK.

So, it is both looking much better, but then a 'horror show'!

I think things are looking much better up until 144, especially on the GFS. People just get upset if it's not showing bitter cold at 192 and beyond!

[Liam J]

Very cold & snowy GEM with snow showers or more prolonged areas of snow at times, just speculation at this range though

[Ali1977]

GEFS also looking much better at 132, SW winds not heading our way

[BLAST FROM THE PAST]

Look for the LP around Iceland that UKMO, GFS and GEM for example show at about t105 to 120. UKMO moves it ESE into Scandi, GEM drops it south almost down over us....both result in increased and elongated cold. GFS drives it through East and pattern flattens. Thats the key feature for me

BFTP

Edited January 9, 2013 by BLAST FROM THE PAST

[SMU]

THe GEM toying with the sliding undercutting scenario again...

Enjoying the outputs again-

People looking for the End missing the upgrades in the middle....

S

[Cumulonimbus Tower]

The GFS upstream whilst still not totally with the others holds back enough energy to clear the low ene.

This buys us some time, a decent trend at least from it.

I was looking at the GFS and thinking something similar myself. Whilst it still goes woefully wrong it certainly does it in a less dramatic way than this morning, so you could view it as starting to come back on board as opposed to standing firm with a new idea. I'm trying to keep positive and the METO chart certainly has helped but tonights ECM feels crucial now and i shall be watching it from behind the sofa, pack of prozac in one hand and bottle of Johnny Walkers in the other

[The PIT]

Todays 12 oz follows the ECM from the day before. The last ECM followed the previous GFS run. Still none the wiser as to how long the cold snap will last 48 hours or longer.

[johnholmes]

I'm confused, chaps.

I am a mere beginner to all this and read this (and other) threads with great interest. However, I am baffled when I read two very authoratitively written contributions, placed almost consecutively on a page where the first one reads "12z GFS looking good, much better than the 0z" and the subsequent post, refering to exactly the same model run reads "12z GFS a complete horror show".

How can this be? Surely there is only one way to read a model and everyone commenting on the models in the run understands what they are looking and how to interperet the results, so why such disparity in the comments?

hello S

I am not surprised, you can tell how the models are by the mood swings on here. Not easy for someone new to this but you will soon get to know those who post a reasonably objective view of what is being shown by the different models.

Try looking in the more technical area, it is much less busy so like a lot you may find it boring but it will give you each day, without naming names, several folk posting a more balanced view of what may happen.

enjoy the site, remember there is far more to the site than the forum area, lots to read in the Guides which should help you in your learning.

[The Eagle]

another run that takes the UKMO,

It takes more the ECM line but not the UKMO. It's chalk and cheese synoptically with the UKMO. Goes to underline the sheer uncertainty. GEFS ensembles are gathering consistency though which for next week is not so good. Hopefully the ECM sticks to it's forecast.

[Cecil Hogmanay Melchett]

It takes more the ECM line but not the UKMO. It's chalk and cheese synoptically with the UKMO. Goes to underline the sheer uncertainty. GEFS ensembles are gathering consistency though which for next week is not so good. Hopefully the ECM sticks to it's forecast.

huh? i thought you said it was moving towards the gfs eagle??

[bradymk]

http://modeles.meteo...em-0-138.png?12

THe GEM toying with the sliding undercutting scenario again...

Enjoying the outputs again-

People looking for the End missing the upgrades in the middle....

S

Yes quite, GEM drops that low directly south over us, undercutting and its a shame we cant see up to 240 on the 12z run. I think this is the sort of route the ECM will take tonight (hopefully) with the low near iceland sliding southwards. A very plausible outcome I feel and it fits in with the Metoffice forecast of sleet/snow moving southwards on Monday.

[garbagebags]

Is it strnge that the GFS see these shortwaves and the other models dont? Much better fight from the GFS but still needs work to win the fight

[cold snap]

Well who would be a weather forecaster ?

Ian if you are reading this ,must be very hard right now ?

Gem holds on the cold , I don't how but it does , thought for a minute going Gfs way ,what do I know

[Summer Sun]

This is the latest take for the shorter term from the Met Office 16:00 update

Outlook for Friday to Sunday:

Patchy rain and hill snow spreading east on Friday. Rain and snow affecting the south and west on Saturday. Brighter but colder on Sunday, with wintry showers in the east.

Certainly a risk of snow in the SW on Saturday and Sunday

The risk then transfers east for the new week

Edited January 9, 2013 by Gavin.

[Hammer]

With so much variability past 120 hours in all models, little point in thinking it will verify.

For me T72 to T120 looks pretty good.

[The Eagle]

huh? i thought you said it was moving towards the gfs eagle??

It was earlier. The jet stream pattern around 120 hrs was similar to GFS. Something to keep in mind. It gets there in the end though. NOGAPS follows the ECM throughout which is positive.

GFS ensembles a slight upgrade but overall not that much difference, Still lots of different outcomes.

[Ian Williams]

So why do we now call it a shortwave if it is a low pressure? Confusion of terms? What about high pressure?

H

Its not really a Low Pressure system per se, but on the 500mb charts it shows up as small kinks in the Isobars of a Low Pressure system

More on shortwaves here http://www.theweathe.../habyhints/131/

and here http://en.wikipedia....ve_(meteorology)

Edited January 9, 2013 by Ian Williams

[BLAST FROM THE PAST]

As Steve M says some neartime upgrades. Re GEM, at t144-150 is an incredible set up, better than its 00z. Well where are we heading? i'm off home now, to stop off at my local [The Plough] sink a couple and ponder, then come in and view the ECM

BFTP

[AGAL]

Gem going down the gfs line here,

The low around the Greenland area Stops the ridging off the Greenland high

However things looks cold over the weekend

And the post immediatly before says

"Well its so painful waiting for these runs, GEM currently trickling out, another good run, much better than GFS anyway, huge 6-7pm tonight, more servers may be needed Paul "

So two totally opposed interpretations of the GEM within minutes..

Okay Rybris I get it goodbye

Edited January 9, 2013 by AGAL

[Hotspur62]

Just got in from work and looked at latest GFS run and looks like a 5 day cold spell before milder air comes in from Atlantic.After seeing GFS 00hr run this morning it appears a milder trend is developing which is disappointing Hope next run shows improvement and comes into line with ECM from this morning but this has makings of another disappointment for a good long cold spell.Feels like December 2012(when Beast from East never got going!!) going to happen.Heart wants cold spell but head says milder more mobile weather by Thursday of next week.Really hope i am wrong but getting used to disappointments and espicially after previous 4 runs from GFS were positive for a good cold and snowy period.Suppose patience is name of the game!!

[fergieweather]

Well who would be a weather forecaster ?

Ian if you are reading this ,must be very hard right now ?

Gem holds on the cold , I don't how but it does , thought for a minute going Gfs way ,what do I know

Just chuckling at it all with a senior UKMO colleague, actually. Anyway - we await the EC with great interest. At least raw UKMO-GM holds the broad blocked story presently, with Canadian support, but bear in mind it's just the RAW output so it'll be a few hours before I see how Exeter amend it all - or not.

[bradymk]

And the post immediatly before says

"Well its so painful waiting for these runs, GEM currently trickling out, another good run, much better than GFS anyway, huge 6-7pm tonight, more servers may be needed Paul "

So two totally opposed interpretations of the GEM within minutes..

Okay Rybris I get it goodbye

Yes it is confusing with some posts but trust me, I was the one who said the top quote and the GEM is certainly still very good on its 12z output and not following GFS.