Winter Model Discussion 18Z 13/1/13 onwards.

[TheHumph]

How many times have we seen the GFS over cook these Atlantic lows?! I'm don't buy the GFS solution with a 945mb low! With less energy in the Atlantic we would see an evolution more in line with the UKMO. The UKMO has has shown an undercut consistently now for the last 3 runs. Surely this can't continue to be disregarded as a possible solution! This has got Feb 1947 written all over it!

http://i.telegraph.c...ws_1787827i.jpg

Not sure about Feb 1947(!) but I certainly agree that the UKMO is on the right track in terms of undercutting. Also I have seen lots of occasions where the GFS is a little too progressive in terms of bringing the Atlantic in and my feeling is that it will slowly concur with the UKMO over the next few runs. Interesting to see the ECM charts though which may give us a clue!

[swfc]

If im honest i woudnt discount any model at the moment given the current set up.Selective model picking is ok for the mind set but it could go either way regarding the atlantic pushing in or the block holding to the north east.ssw or not the pv does look very stubborn in the mid range for sure and thats as far as it goes imo.

[ChartViewer]

Some seriously cold temps Wednesday night

Edited January 14, 2013 by ChartViewer

[Glacier Point]

alantic running out of puff well it seems to me that its well and truely in control by the end of this week....

so what is your expectation of the current model outputs as they cant all be wrong and seem to be all in agreement at this stage?

and 12z day 10 with 06z for comparison:

and the GEFS temperature anomaly for that time

This I think is a reasonable projection based on the global wind oscillation going through phase 4/5 type evolution. The key point that heights remain strongly below average across Europe. That supports +ve height anomalies to the north and prevents any widespread ingression of the Atlantic.

So low pressure signal in the Atlantic, agree with that. Atlantic powering through across NW Europe on a positively tilted jet - disagree with that, but with the caveat of a less cold spell 20th - 25th Jan is very likely based on the waxing and waning of the downelling stratospheric warming impacts.

[kent]

I personally dont believe in all this talk of undercutting and blizzards. I think the progression of the Atlantic is going to be strong for the block and things will end up with a messy mush for most ending very quickly into the weekend. I expect the ECM to confirm this later. I do hope Im wrong but I feel some of the comments on here are based on unfounded optimism and a reality check is needed concerning these dubious outputs.

[MR EXTREMES]

i must have imagined the four hours of snow today and the four days of sub zero conditions about to begin then. to be followed by either a continuation of the freeze or a snowy breakdown or maybe both.

we cant all have snow and i'm sorry but portsmouth isnt the best place in the country for wintry conditions

ok so my expectations are rather high but winter 09/10 absolutely wipes the floor with winters 11/12 and so far this year.

trouble is the models in year 09/10 were absolutely on the money!

so why is this year been such a let down well perhaps its because the strat has not over powered the vortex to the degree that it did in 09/10 winter and considering its been a fairly good strat event something else has overpowered the strat teleconnetion and the simple answer would be the suns activity,

more powerful vortex stronger jet producing a very unwelcome active alantic which i strongly feel will overpower the feeble heights to our north not allowing any heights to build around a more favoured area like the greenland area which is more favourable for uk wintry weather.

what has been clear is the continued idears of height rise to our north which by far is not showing up on any models simply because the vortex and the alantic are not giving any chance of this outcome so for the shorterm cold midterm cool alantic flow and then futher on who knows anyones guess.

[MR EXTREMES]

and 12z day 10 with 06z for comparison:

and the GEFS temperature anomaly for that time

This I think is a reasonable projection based on the global wind oscillation going through phase 4/5 type evolution. The key point that heights remain strongly below average across Europe. That supports +ve height anomalies to the north and prevents any widespread ingression of the Atlantic.

So low pressure signal in the Atlantic, agree with that. Atlantic powering through across NW Europe on a positively tilted jet - disagree with that, but with the caveat of a less cold spell 20th - 25th Jan is very likely based on the waxing and waning of the downelling stratospheric warming impacts.

thank you for your reply intresting.

[swfc]

Ecm due out shortly and not expect any change if there is to be one up to the 144 hr mark ie pressure rising or orientation to the north east.

[TheHumph]

I personally dont believe in all this talk of undercutting and blizzards. I think the progression of the Atlantic is going to be strong for the block and things will end up with a messy mush for most ending very quickly into the weekend. I expect the ECM to confirm this later. I do hope Im wrong but I feel some of the comments on here are based on unfounded optimism and a reality check is needed concerning these dubious outputs.

Some of the comments may sound optimistic but are based on what the consistant UKMO model is showing. If you are basing your comments on what the GFS shows (and what you think the upcoming ECM will show) that is your perogative. But the opposite of optimism is pesimism which you could be said to be showing!

[snow mad]

ok so my expectations are rather high but winter 09/10 absolutely wipes the floor with winters 11/12 and so far this year.

trouble is the models in year 09/10 were absolutely on the money!

so why is this year been such a let down well perhaps its because the strat has not over powered the vortex to the degree that it did in 09/10 winter and considering its been a fairly good strat event something else has overpowered the strat teleconnetion and the simple answer would be the suns activity,

more powerful vortex stronger jet producing a very unwelcome active alantic which i strongly feel will overpower the feeble heights to our north not allowing any heights to build around a more favoured area like the greenland area which is more favourable for uk wintry weather.

what has been clear is the continued idears of height rise to our north which by far is not showing up on any models simply because the vortex and the alantic are not giving any chance of this outcome so for the shorterm cold midterm cool alantic flow and then futher on who knows anyones guess.

I didn't think we were meant to have the full effects of the SSW until around the 25th... so you can't blame the ssw just yet

[Froze were the Days]

Nice to see the stubborn GFS continues in the same vein of the last couple of days or so and that's to bring the Atlantic in from the west (very consistent it has to be said) - UKMO continues the undercut but in theory by 144 I feel the majority of the UK will be in milder conditions after initial snow towards the southern and central parts, can't help feeling the ECM will revert back to a similar pattern like the GFS has been showing.

What ever happened to the heights towards the north west as shown by some pressure anomaly models, not showing up in general on the op runs.?

Edited January 14, 2013 by Froze were the Days

[Timmytour]

How many times have we seen the GFS over cook these Atlantic lows?! I don't buy the GFS solution with a 945mb low! With less energy in the Atlantic we would see an evolution more in line with the UKMO. The UKMO has has shown an undercut consistently now for the last 3 runs. Surely this can't continue to be disregarded as a possible solution! This has got Feb 1947 written all over it!

http://i.telegraph.c...ws_1787827i.jpg

I often see claims about the GFS overcooking Atlantic lows. But within the past week we've had situations where the GFS was holding the Eastern block in place while the ECM was powering through it.

I believe....maybe hope is a better word... that the GFS is subject to correction and will end up giving us the undercut we want and the increasingly cold uppers approaching us from the north east. Perhaps the 18z might introduce this in stark contrast to the previous runs, only for it to backtrack and then slowly come back to it. That's a way I often see the GFS going in FI. However the current situation really is on a knife-edge and it's no surprise to see different models fall on different sides of the fence and go onto to produce starkley different results. Whichever gets it right will gain kudos, but it really won't guarantee that it will correctly be the one to model the next knife-edge situation

[Froze were the Days]

JUST IN!! BBC weather going for UKMO, brilliant stuff

So that means it's going to happen then? - don't forget it was just yesterday that Exeter 'watered' down their FAX charts in correlation to some of the other models.

[Mucka]

BOM

[nick sussex]

Very good ECM 72hrs,much better than the GFS . I expect the ECM will back the UKMO this evening, the 96hrs should be interesting.

[kev238]

impossible to make a prediction for the end of the week. I think some kind of Atlantic attack is inevitable but the direction and angle is open to debate!! I think there i clearly a chance of a significant snow event but then it may well get washed away!

[Continental Climate]

Not a bad 72 http://www.meteociel.fr/modeles/ecmwf/runs/2013011412/ECH1-72.GIF?14-0!! easterly in place by thursday

[fergieweather]

ARPEGE evolution and 850's support UKMO-GM almost exactly up to 00z Fri. Colder air somewhat further west compared to GFS.

[SnowBallz]

I personally dont believe in all this talk of undercutting and blizzards. I think the progression of the Atlantic is going to be strong for the block and things will end up with a messy mush for most ending very quickly into the weekend. I expect the ECM to confirm this later. I do hope Im wrong but I feel some of the comments on here are based on unfounded optimism and a reality check is needed concerning these dubious outputs.

I have to say, I'm a bit miffed at the bullish nature.

If anything, it could be said that - prior to output of the last 24-36hrs - talk of a strong block were "unfounded" or "optimistic". However, the most recent NWP output has moved towards a general broad juxtaposition, which agrees with a stronger NE blocking signal.

We've seen strong consistency from the UKMO model, and this was further added to with the 12z - albeit slightly watered-down, yet broadly in-line with previous outputs. It's very much sticking to its guns - even though, 'That UKMO' was considered so extreme, that Exeter heavily modified it.

For what it's worth, I really don't think anything will be decided for this weekend in the current outputs; that would belie confidence in the current NWP which, as we know, is currently plagued with record variance. Personally, I imagine the 12z ECM to - if anything - move closer to the UKMO, be it very subtle changes.

[IDO]

The GEFS 2m mean from the 12z is showing a return to just below average temps after the next 4/5 days:

The GFS control, run after run, is echoing the op, as is the mean. Variations on a theme as to when the Atlantic breaks through.

Hoping the GFS is as bad as the experts on here hint at. UKMO would give the south a white out before it probably thawed. Better than nothing.

ECM at T96:

Edited January 14, 2013 by i'm dreaming of...

[Cloud 10]

ECM at 96 hrs.

Feeling bitterly cold on Friday with a biting SE wind.

[Tony Beets]

undercutting???

[SnowBallz]

ARPEGE evolution and 850's support UKMO-GM almost exactly up to 00z Fri. Colder air somewhat further west compared to GFS.

Wow. Thanks Ian for sharing that with us

I did mention earlier that I thought we were approaching a tipping point in this saga, and I think Ian's confirmation of solid ARPEGE support for the UKMO-GM is representative of this.

Excellent developments, and sets us up nicely for the week ahead...

[That ECM]

I have to say, I'm a bit miffed at the bullish nature.

If anything, it could be said that - prior to output of the last 24-36hrs - talk of a strong block were "unfounded" or "optimistic". However, the most recent NWP output has moved towards a general broad juxtaposition, which agrees with a stronger NE blocking signal.

We've seen strong consistency from the UKMO model, and this was further added to with the 12z - albeit slightly watered-down, yet broadly in-line with previous outputs. It's very much sticking to its guns - even though, 'That UKMO' was considered so extreme, that Exeter heavily modified it.

For what it's worth, I really don't think anything will be decided for this weekend in the current outputs; that would belie confidence in the current NWP which, as we know, is currently plagued with record variance. Personally, I imagine the 12z ECM to - if anything - move closer to the UKMO, be it very subtle chang

His location will tell you why he is bullish. We live in a poor are for cold and snow. The latest output for many is very good though.

[danm]

WAY TOO PROGRESSIVE 96 hour ECM!!! bin it

I would hardly call this "progressive":