Winter Model Discussion 06Z 10/01/13>

[egret]

Presumably what we have are two possible outcomes and maybe both could be produced by either ECM or GFS, it just being that on balance the probability falls one way on ECM and the the other way for GFS. This being so we must surely consider both. This is where trends and ensemble support comes in, leaving GFS on the face of it 'wrong and likely to change' in the face of wider view of probabilities, but nonetheless 'respected and one to keep an eye on' as a possible(if less probable) outcome?

If each model could present the range of possible outcomes and probabilities I suspect we would all be even more confused and perplexed!

The current position is surely is to be expected early on in blocking situations where UK lies in the borderline (battleground) location. Once the SSW impacts (midweek?) I would expect us to be more firmly within the Continental zone and less vulnerable to variations associated with Atlantic influence. (i.e mainly cold and dry except for 'eastern seaboard' areas or possibly South coast if the air moves in from SE.

Please put me right if my understanding is incorrect.

[Southender]

Greenie HP and N/NE flow by the end of high res?

[BLAST FROM THE PAST]

GFS 06z, jet is changing angle and LPs digging on a more southerly track. Its beginning to show subtle changes.

BFTP

[Shunter]

06z T126 - Jet flow moves further South, enables pressure rise around Iceland ...could this signal the change to a rapid build ?

[Methuselah]

[Harsh Climate]

The 06z looks as flat as a pancake! I know the models are all over the shop at the moment but the consistency of the GFS in the last few runs cannot be ignored. In my opinion i think the other models eill now start to fall in line with what the GFS is predicting. I expect by tomorrow afternoon we will have agreement across the models on a return to zonal weather by wednesday next week.

I agree fully with that, hope I am wrong but just cannot see the gfs fully backtracking in such an early time frame.

At long range I find the gfs can be woeful and churn out vastly different runs through the day whereas the ECM can be quite steady at picking up early signals. But at close range I would certainly choose the gfs over the ecm..

[The Eagle]

ECM has moved more in line with GFS this morning rather than the other way around. Granted ECM still has potential but I have just looked at NOGAPS 6z - it's GFS light. Nice forecast for the model and one which everyone will take in to account in the future after this. No doubt at all GFS has it nailed.

[The Weather Dragon]

GFS is Bullish - a zonal flow next week. I am an avid coldie but the odds must be in favour of a return to zonality - if GFS pulls this off then ECM/MET models reputation will be seriously damaged.

[nick sussex]

This is one of the best NOAA state discussions I've seen. This from the Michigan one. Full of detail and talks about the SSW:

AS A BIT OF AN ASIDE...INTERESTING TO NOTE SOME OF THE GUIDANCE

TRENDING AWAY FROM A VERY COLD AIR PUSH INTO THE GREAT LAKES (WHAT`S

NEW THE PAST 4 YEARS?). PER LATEST 30-50MB PLOTS...STRONG

STRATOSPHERIC WARMING (NEAR RECORD-SETTING) CONTINUES TO PROPAGATE

NORTHEASTWARD FROM THE HIMALAYAS TOWARD THE NORTH POLE...WITH A

DOWNWARD WARMING TREND NOTED TOWARD 100MB IN THE LATEST PROGS. THIS

CONTINUES TO STRONGLY SUGGEST AN IMMINENT SPLIT OF THE POLAR

VORTEX...WITH FORCING VECTORS SUGGESTIVE THAT SOME TRULY ARCTIC COLD

AIR WILL DRAIN DOWN INTO MUCH OF CENTRAL AND EASTERN CANADA. THE BIG

TRICK IS TRYING TO GET THIS DOWN INTO THE LOWER 48...AND THE LACK OF

STRONG NORTH ATLANTIC BLOCKING (NEGATIVE NAO) IS NOT HELPING

THINGS...POTENTIALLY ALLOWING MUCH OF THE COLD TO JUST SKIRT THE

REGION. AS SUCH...AND GIVEN SUCH A COMPLICATED SCENARIO...NOT

SURPRISING TO SEE SOME OF THE LATEST GUIDANCE (ECMWF STARTED IT LAST

NIGHT) TRENDING HEAVILY IN THIS DIRECTION...AND TRULY CALLING INTO

QUESTION THE PROBABILITY WE CAN GET ANY SUSTAINED BELOW NORMAL CHILL

DOWN THIS FAR SOUTH. HOWEVER...THERE ARE ALSO ISSUES RELATED TO THE

MODELING OF THE PNA AND HEIGHT RIDGE INTO ALASKA...AND HOW THAT

IMPACTS THE POSSIBILITY OF ENERGY BEING LEFT OVER THE FOUR CORNERS

VERSUS CONNECTING UP TO A MORE FULL LATITUDINAL TROUGH OVER THE

EASTERN CONUS. THE END RESULT: THE POSSIBILITY FOR COLD IS

DEFINITELY STILL THERE...BUT CONFIDENCE IN JUST WHEN IT MIGHT ARRIVE

OR HOW LONG IT WILL STICK AROUND REMAINS QUITE LOW.

[Weather Boy]

Ian,

Not sure about astonised, as only 11 members are going with this Run.

Yes, query for Ian.

Why would you be "astonished" please? The GFS is out on its own more or less without any support at all. It could be leading the way and correct, but surely using the word 'astonished' calls for an explanation. I am genuinely interested as to how and why you can hold this view.

If it's, as you've alluded to before, a simple application of percentages that the mildest option is often the correct one then, without wishing to be rude, I think that we can safely discard your opinion as it is completely unscientific. However, if there is a more logical reason, then I would be pleased to hear it so that I can re-appraise my own novice view.

[Harsh Climate]

And in my eyes the gfs is bad as early as 96H

Once that high pressure starts sinking south east over us, with low pressure systems to the west of it pushing south east also (not going favourably north east up the western side of greenland), I do not say any way back into something as favourable as what the ECM has been showing. That's certainly upto 180h, after that is anyones guess, but FI never the less.

Edited January 10, 2013 by Harsh Climate

[The Weather Dragon]

This weekends cold is now also downgraded from previous runs - especially south of the midlands

Edited January 10, 2013 by Jonathan Evans

[bluearmy]

ECM has moved more in line with GFS this morning rather than the other way around. Granted ECM still has potential but I have just looked at NOGAPS 6z - it's GFS light. Nice forecast for the model and one which everyone will take in to account in the future after this. No doubt at all GFS has it nailed.

nogaps is flip flopping. no kudos there. just as i thought the debate was improving, you made that post. how on earth can you say that any model has this 'nailed'. given where we have come from and seen through this week, its a terrible statement to make.

[SP1986]

ECM has moved more in line with GFS this morning rather than the other way around. Granted ECM still has potential but I have just looked at NOGAPS 6z - it's GFS light. Nice forecast for the model and one which everyone will take in to account in the future after this. No doubt at all GFS has it nailed.

you're brave man that says that on a thread like this. 'm siding with that idea, the GFS early on shows energy towards Labrador, and there's alot of it being sent out, perhaps that stream of energy is too much for the blocking high. On the GFS the blocking high becomes considerably weaker and the Atlantic battles through. I'd argue without a strong Greenland or Arctic high, there's nothing to tie it down.

If the cold is going to win through, the blocking high will have to repell the energy and continue growing west, or perhaps develop a shortwave on its northeastern flank.

At the moment I would say slightly in favour of the GFS owing to it's unwavering consistency.

[SMU]

http://modeles.meteociel.fr/modeles/gem/runs/2013011000/gem-0-108.png?00

this chart is probably the best to use for newer people-

You have an area of energy ( PVA / Shortwave ) whatever you want to call it at 1005 MB SE of Iceland / NW of scotland-

We have a high building NE in the atlantic- we have a receeding block to the NE @ 1030 MB over Western scandi-

the flow over the UK is Easterly & that dark blue blob over east anglia is the upper air cold pool ~ -11c @ 850 HPA-

The jet is trying to loop like an n shape around the high pivoting over iceland & moving back south towards france-

Because its this shape the low over iceland moves SOUTH

http://modeles.meteociel.fr/modeles/gem/runs/2013011000/gem-0-114.png?00

http://modeles.meteociel.fr/modeles/gem/runs/2013011000/gem-0-120.png?00

http://modeles.meteociel.fr/modeles/gem/runs/2013011000/gem-0-126.png?00

heres the all important jet

http://modeles.meteociel.fr/modeles/gem/runs/2013011000/gem-5-102.png?00

because this moves south the ridge in the atlantic builds north & then bends east & cojoins with the high over Scandi, then the uk is trapped under the very cold air moving west & the locale of the high is atlantic- south of iceland- scandi-- good place-

http://modeles.meteociel.fr/modeles/gem/runs/2013011000/gem-0-144.png?00

now look at the GFS

http://modeles.meteociel.fr/modeles/gfs/runs/2013011006/gfs-5-120.png?6

the jet is faster at 120 & MUCh more easterly curvature-

& the net result of the energy-

http://modeles.meteociel.fr/modeles/gfs/runs/2013011006/gfs-0-108.png?6 the low scoots through east-

leaving the ridge locale- atlantic, scotland & norway- with nothing propping up the high it will sink across us-

Watch the 06 & 12z ENS suite & the speed ofthe jet- slow it down just a bit- more amplitude- big change to the euros-

If the euros speed it up then a big movement to the GFS...

S

[Iceaxecrampon]

BBC (In association with the Met Office) going for a light dusting Mid Wales - Midlands this weekend.

Another non event generally?

Most ppn is South - Netweather has 73% chance snow for London.

Risk chart ties in with METO - best for Wales and Midlands

Temps -8 min South Wales the place to be.

Confused if not slightly disappointed....

Ian

[Tim Bland]

At Least the GFS shows us that even if it does go Pete Tong early next week then we could be looking at a reload by next weekend. Remember the strat warming is putting pressure on the the PV so its only a matter of time before higher pressure squeezes into the gaps and sends the cold / unsettled weather south or builds a full ridge. 10 days out on the GFS 06z shows a very snowy picture for most as the pv sinks over us and WAA is sent up to greenland on its western flank.

Please no wrist slitting later if ECM / UKMO move more towards GFS as its not game over.. its just the beigining as GP mentioned earlier and still 6 weeks to go before its even March.

[Southender]

Way out in lala land.

But anyone seen the PV?!

[Jonan92]

The chinese has some amazing charts, it's crazy the amount of options that are at t144

[Weathizard]

Having had a closer look at the charts this morning, can safely say the UKMO (The best performing model at day 5) is the best by far, far less messy than all the others. And the ECM has NOT backtracked people saying it has are wrong, it is not the same as the GFS by a long stretch, yes it brings warmer air in earlier but not in the way the GFS does and we still get the weak Greenie high, its actually very similar to the last two runs just not enough cold air about and wrong tilt.

Still very much up in the air I'd say, something has to give..

[Harsh Climate]

ECM has moved more in line with GFS this morning rather than the other way around. Granted ECM still has potential but I have just looked at NOGAPS 6z - it's GFS light. Nice forecast for the model and one which everyone will take in to account in the future after this. No doubt at all GFS has it nailed.

I can just see the 12z's nailing the coffin firmly shut! Think we are going to need a minor miracle now to see a turnaround in the gfs at such a late stage!

If the gfs does come up trumps which I am suspecting the other models will really have performed atrociously with the GFS head and shoulders above the rest.

[TEITS]

Just reanalysed this mornings output and the mist for me is clearing a little. After viewing the 06Z especially the +60 to +96 timeframes I looked at the ECM/UKMO and I think a kind of blend of all output is more likely. What I mean by this is im unconvinced of the SW sinking S bringing cold E,lys i.e GEM/CMA although that is my preferred option. I feel we will see more energy going SE than the GFS suggests but I also feel the HP to our W will be held further W and so will the LP near Greenland. So at this point I feel the UKMO is probably the most likely to be correct.

So for the 12Z keep a very close eye on that SW between +60 to +90.

[Snowfan50]

This is one of the best NOAA state discussions I've seen. This from the Michigan one. Full of detail and talks about the SSW:

AS A BIT OF AN ASIDE...INTERESTING TO NOTE SOME OF THE GUIDANCE

TRENDING AWAY FROM A VERY COLD AIR PUSH INTO THE GREAT LAKES (WHAT`S

NEW THE PAST 4 YEARS?). PER LATEST 30-50MB PLOTS...STRONG

STRATOSPHERIC WARMING (NEAR RECORD-SETTING) CONTINUES TO PROPAGATE

NORTHEASTWARD FROM THE HIMALAYAS TOWARD THE NORTH POLE...WITH A

DOWNWARD WARMING TREND NOTED TOWARD 100MB IN THE LATEST PROGS. THIS

CONTINUES TO STRONGLY SUGGEST AN IMMINENT SPLIT OF THE POLAR

VORTEX...WITH FORCING VECTORS SUGGESTIVE THAT SOME TRULY ARCTIC COLD

AIR WILL DRAIN DOWN INTO MUCH OF CENTRAL AND EASTERN CANADA. THE BIG

TRICK IS TRYING TO GET THIS DOWN INTO THE LOWER 48...AND THE LACK OF

STRONG NORTH ATLANTIC BLOCKING (NEGATIVE NAO) IS NOT HELPING

THINGS...POTENTIALLY ALLOWING MUCH OF THE COLD TO JUST SKIRT THE

REGION. AS SUCH...AND GIVEN SUCH A COMPLICATED SCENARIO...NOT

SURPRISING TO SEE SOME OF THE LATEST GUIDANCE (ECMWF STARTED IT LAST

NIGHT) TRENDING HEAVILY IN THIS DIRECTION...AND TRULY CALLING INTO

QUESTION THE PROBABILITY WE CAN GET ANY SUSTAINED BELOW NORMAL CHILL

DOWN THIS FAR SOUTH. HOWEVER...THERE ARE ALSO ISSUES RELATED TO THE

MODELING OF THE PNA AND HEIGHT RIDGE INTO ALASKA...AND HOW THAT

IMPACTS THE POSSIBILITY OF ENERGY BEING LEFT OVER THE FOUR CORNERS

VERSUS CONNECTING UP TO A MORE FULL LATITUDINAL TROUGH OVER THE

EASTERN CONUS. THE END RESULT: THE POSSIBILITY FOR COLD IS

DEFINITELY STILL THERE...BUT CONFIDENCE IN JUST WHEN IT MIGHT ARRIVE

OR HOW LONG IT WILL STICK AROUND REMAINS QUITE LOW.

Good find, So really its the damn NAO that is not playing ball.

[The Eagle]

nogaps is flip flopping. no kudos there. just as i thought the debate was improving, you made that post. how on earth can you say that any model has this 'nailed'. given where we have come from and seen through this week, its a terrible statement to make.

NOGAPS is not flip flopping. It's the same as the 00z. Are you denying the ECM has moved toward the GFS? It clearly has. GFS is by far the most consistent now. I am not saying no chance. If the 12z has some miraculous turn around fair enough. Right now even the most biased would acknowledge we have moved toward the GFS this morning and the GFS is most consistent and frankly at 84 hrs is most likely to be right. You disagree with this. Let's see what the 12z's come up with but I really think GFS has this unfortunately.

Edited January 10, 2013 by The Eagle

[garbagebags]

The chinese has some amazing charts, it's crazy the amount of options that are at t144

Its crazy the amount of options at 96!