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Captain Shortwave

Model Output Discussion - The final stretch to Christmas

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Wouldn't be surprised if a north easterly or easterly was eventually progged in the next couple of runs. Seems to be gradually moving that way.

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Comparing like for like, The ECM 12z does look better than the 00z output.

 

The blocking high pressure is further north and west.

 

ECH1-144.GIF?22-0

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And some... based on T+126, 132 etc. V cold/wintry NE'ly undercut as the low centre transits SE.

Evening Ian,

I take it that undercut would run down the uk IF the track is as modelled,notjust for the S/E

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That,s a promising UK T144 chart and continues the possibility of further ridging north or north east.

I think there is enough in the models so far to remain upbeat.

We have a chilly Christmas and Boxing day with frosts and then a reasonable prospect of snow for some areas around the 28th,even at lower levels.

Beyond that a cold High maybe?

It,s certainly too far out to worry about the Atlantic returning.Let,s see where we go with the track of the post Christmas low.

 

 

I certainly hope so Phil, if HP sets up shop over us or the near continent it's alot more stable for cold than relying on an undercutting atlantic, I'm very worried about GFS though which I still feel is the best model, though none are infallible of course.

 

I'm praying for the Euro's to be correct. :)

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All models showing the Alaskan Ridge topple and the wave from the sliding heights push the Canadian PV towards our sector. Its hard to imagine this not collapsing any pressure build north of the UK:

 

ECMpost-14819-0-56552600-1419274087_thumb.p

 

An inevitability of the pattern flattening if we cannot sustain the heights in Alaska/Pacific. Though ECM D10 teases are always a possibility...

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Very disappointing output this evening.

 

Not only are we set not to get any cold blast, it looks like the storm won't be too intense either.

 

Hopefully things will look better come the New Year.

 

I suppose the UKM is the best of a bad lot.

 

---- The GFS Ensembles offer some hope and i would still suggest there is a good deal of uncertainty

Edited by Matty M

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I certainly hope so Phil, if HP sets up shop over us or the near continent it's alot more stable for cold than relying on an undercutting atlantic, I'm very worried about GFS though which I still feel is the best model, though none are infallible of course.

I'm praying for the Euro's to be correct. :)

I think the UK at T120 is the best for ridging later.Just slightly more amplification than the the ECM even,and I think would give a better chance of a high building further north.

Subtle differences I know but in this situation it could just mean less energy goes north after the low tracks into the continent.

A fascinating period of chart watching and very difficult to see a consistent trend beyond this week.

Edited by phil nw.

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Like some I must admit to feeling deflated now given the mo.Granted its still subject to change but was looking towards a wintry"snow type"xmas period.Still not a flat zonal outlook and hopefully things will change to a more wintry outlook during the coming weeks

Edited by swfc

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I think the UK at T120 is the best for ridging later.Just slightly more amplification than the the ECM even,and I think would give a better chance of a high building further north.

Subtle differences I know but in this situation it could just mean less energy goes north after the low tracks into the continent.

A fascinating period of chart watching and very difficult to see a consistent trend beyond this week.

 

 

Yes phil UKMO is slightly better than ECM if you want less energy going over the top of the high and allowing HP to build further northeast but I still like ECM 12Z as it builds a strong high pressure cell over central Europe which would keep us cold and dry for quite sometime, nothing mild on the euro's after tomorrow.

 

 

Like you say its fascinating to watch with many twists and turns to come for sure.

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ECM finishes with HP to the East and an attempt to ridge into Scandinavia, albeit the orientation of the High on that chart wouldn't help us much in terms of getting a good Easterly.

 

 

 

 

ECM1-240.GIF?22-0

 

However, it's good to see a few runs suggesting height rises towards Scandi; we now need to see if that becomes a trend.

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Interesting how the ukmo 12z at T+144 hours with its anticyclone Sat on top of the UK bears absolutely nothing in common with this afternoons met office update of snow showers in the north spreading south which would indicate a Northerly flow next week..more questions and no answers yet.

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Interesting how the ukmo 12z at T+144 hours with its anticyclone Sat on top of the UK bears absolutely nothing in common with this afternoons met office update of snow showers in the north spreading south which would indicate a Northerly flow next week..more questions and no answers yet.

I think things have moved on frosty mo wise since that outlook was released.Possibly the update will show the drier chilly outlook if mostly dry

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I think things have moved on frosty mo wise since that outlook was released.Possibly the update will show the drier chilly outlook if mostly dry

What a pity that would be, was looking forward to a good northerly.

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Just a little thought, in reaction to yet another different run from the ECM: out of the last 20 GFS parallel runs, I think at least 16 of them have had low heights in the north sea and winds from a northerly direction for this Sunday. It seemed a but if a fantasy when it started turning out such charts at T240, but it has largely stuck to its guns and now has a fair chance of verifying reasonably well. At the same time, the ECM was consistently putting low pressure not far from Iceland. So is the GFS(P) potentially a step forward for models in these circumstances? Early days but maybe a bit? - But it still struggled with the phantom Greenland High, so still more work to be done!

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ECM finishes with HP to the East and an attempt to ridge into Scandinavia, albeit the orientation of the High on that chart wouldn't help us much in terms of getting a good Easterly.

 

 

 

 

ECM1-240.GIF?22-0

 

However, it's good to see a few runs suggesting height rises towards Scandi; we now need to see if that becomes a trend.

 

Would be nice for cold-lovers to see the chart below become a trend over the few days and the jet digging south,

as we all know the Atlantic as big problems dealing with these situations....but and yes lots of B.U.T.S of late,,,,, we will see.

 

ECM101-240_uwx5.GIF

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I must be one of the few members to be relatively happy with this evening's output, which looks relatively seasonal for the reliable. Could do with a drier day on Saturday, admittedly.

I promise my sanguine outlook is nothing to do with UKMO cooking up a snowy noreaster with Epping Forest's name on it on Christmas Sunday!

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I must be one of the few members to be relatively happy with this evening's output, which looks relatively seasonal for the reliable. Could do with a drier day on Saturday, admittedly.

I promise my sanguine outlook is nothing to do with UKMO cooking up a snowy noreaster with Epping Forest's name on it on Christmas Sunday!

I am also very pleased.  There are chances of upgrades.  The next day's worth of model runs will be of great interest. :)

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I think the trend for pressure rises to our NE has moved up a notch tonight. It's a subtle trend but if we compare to what we were seeing yesterday morning there was absolutely zero northern blocking showing anywhere to our NE.

I'd assumed the GEFS would be terrible tonight based on what I've been reading, but to be honest having actually looked through them, they look better than yesterday with further hints at heights to our East and northeast.

The METO 144 chart is easily the most wintry of the season albeit it doesn't look dramatic like a big northerly. If that comes to pass parts of England could see an ice day I'd imagine. I personally don't rate the meto 144 so I'm very wary of this. It's always seemed poor to me at that range whereas at shorter range it's the 'go to' model. It's certainly a credible solution though.

We will probably end up with a nice mild easterly as per ECM :-)

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I think the trend for pressure rises to our NE has moved up a notch tonight. It's a subtle trend but if we compare to what we were seeing yesterday morning there was absolutely zero northern blocking showing anywhere to our NE.

I'd assumed the GEFS would be terrible tonight based on what I've been reading, but to be honest having actually looked through them, they look better than yesterday with further hints at heights to our East and northeast.

The METO 144 chart is easily the most wintry of the season albeit it doesn't look dramatic like a big northerly. If that comes to pass parts of England could see an ice day I'd imagine. I personally don't rate the meto 144 so I'm very wary of this. It's always seemed poor to me at that range whereas at shorter range it's the 'go to' model. It's certainly a credible solution though.

We will probably end up with a nice mild easterly as per ECM :-)

Job to know if that is a tongue in cheek comment ??? It doesn't look nice and mild to me

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Just a curious question. Why not look back to what a model was showing last week or 4 days ago and see if it has verified this week or 4 days hence? It just seems logical to me to try to see what was predicted (fair enough there will be various different scenarios) and what actually occurred in order to gain some idea of how accurate those various predictions were. I know there are verification stats available for each model but I rarely see anyone posting / confirming what has happened against what was predicted.

 

 

Welcome, the models tend to trade off spells of doing relatively well but this coming period is a more complex challenge than they often face, so how they've done in past week or so would be generally inconclusive. Also this zonal pattern has been easier for them and errors were much smaller than what we're likely to find looking back from the 27th. Experienced model watchers develop ideas about what models do in certain situations and what their strong or weak points might be. GFS used to be a bit notorious for over-deepening lows at 5-7 days then backing off towards actual time. GEM is often thought to be too prone to over-amplification. European is regarded as most likely to verify when there's a conflict, but not by a wide margin. This coming situation is low on analogues and high on uncertainty even today. A good guess might be made by considering which way each model has trended past three days and seeing if those trends point to a convergence point. The best forecast at any given point is probably the accumulation of least error after weighting the models by preference. At the moment, you could assume that a moderately deep low will cross northern Scotland around the 27th and head towards southern Norway or Denmark by the 28th but possibly factor in that it might head more south than southeast. What actually verifies could be different from what any model shows today. There have been situations in the past where no guidance was all that close at day 6, but this is rare nowadays.

Edited by Roger J Smith

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Job to know if that is a tongue in cheek comment ??? It doesn't look nice and mild to me

I think he's comment maybe meant to be, it'll start off that way at 240h!!!

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Job to know if that is a tongue in cheek comment ??? It doesn't look nice and mild to me

It was tongue in cheek :-) albeit I wouldn't discount it!

Ironically it would probably feel quite cold at ground level even though it's mild aloft.

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