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General Model Output Discussion


reef

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a question for the more experienced please. How come we just dont see weather conditions such as severe prolonged cold weather and snowy days like so many of our older generation have experienced in years gone by. I knw the charts werent as updated as now but they still must have picked up on a trend, showed dream synoptics and then FOLLOWED them through but now when we nearly have cross model agreement and persistant trends to very cold snowy weather and then even the forecasters sticking their heads out only for the next day models to downgrade and lose their potential? The models seem to, infact everytime we have a cold spell the models just drain it out. This often didnt use to be the case so whts gone wrong? and this cannot be put down to global warming. Once a mild, very wet spell looks to get established -it does! and without any real let downs either!! Grateful for any replies adam

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Posted
  • Location: dublin
  • Location: dublin

I think that most people would prefer a good dumping simply because we can't be sure that good synoptics (more than 5+days away) will bring about a prolonged cold spell. In modern times, good synoptics have nearly always ended in major disappointment.

Also, to be be totally honest, I don't think a even larger teapot is capable of producing a cold spell of more than 7 days or so - anywhere in England anyway. At least it hasn't in my lifetime, and I'm 27 now.

I would take a good short-term cold snap - with a good dumping - especially as where I live in the south east of England always seems to be too sheltered for the worst of the snowfall - we only got 2 inches recently, despite the south east being battered by snowstorms!

Either way, I hope everyone gets the snow you want. Here's to keeping our fingers crossed.dry.gif

Slightly disagree with this think its about 50 50..Some people would prefer a longer shot of cold weather.than one snowy day.

Perhaps the management can do a Survey on here would be good reading

Edited by cold snap
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Posted
  • Location: Bishops Stortford
  • Location: Bishops Stortford

Slightly disagree with this think its about 50 50..Some people would prefer a longer shot of cold weather.than one snowy day.

True, I don't doubt that. My point was only that most people probably don't believe a sustained long-term cold period will happen. If it did, we'd take it. But because many are probably dubious, they would prefer a good short-term dumping (at a short-term range) over good long-term synoptics which might not materialise anyway.

Edited by Matt12
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Posted
  • Location: Near Matlock, Derbyshire
  • Location: Near Matlock, Derbyshire

I tend to find these updates tend to be a few datasets behind however. Sometimes the forecaster just chucks the output in the bin and backs their instincts, but most of the time they tend to follow the models rather than the models following the written update, if you know what i mean

Agree totally. I brought this point up last year but was shot down in flames for suggesting it by some quarters. I still 100% believe the further outlooks are prepared the day before they are actually published as they are so often well behind the latest developments.

The outlook looks cold for the foreseeable future across northern Britain, but its looking like an increasingly shortened cold snap for southern counties before milder conditions return once more. Of course this may change over future runs, but I know where my money would be going.

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Posted
  • Location: Peterborough N.Cambridgeshire
  • Location: Peterborough N.Cambridgeshire

You got to admit if the GEM model came true then that would be amazing! the bigger picture is always the key for better events :(

The GEM output is what the Met O seem to suggest in their forecast.

During next weekend they refer to a cold N,ly flow with snow showers in N/E areas. This suggests there is an E,ly element in the N,ly flow rather than a W,ly. This isn't what the ECM shows but is rather more like the GEM.

The reason I was very keen on looking at the Met O forecast today is due to the model uncertainity but also the possible data issues. In these situations we need the human touch when it comes to forecasting. The Met O outlook suggests a Greenland HP bringing N/NE,lys across the country next weekend.

Overall im happy but I would prefer the GFS/ECM/UKMO to trend towards the GEM especially on tomorrows outputs.

Just read a few posts above about the Met O output. The reason the forecast is different to the ECM is because they are obviously basing this on the ECM ensembles. This is nothing to do with using old datasets.

Edited by THE EYE IN THE SKY
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Posted
  • Location: hertfordshire
  • Location: hertfordshire

Even the ECM northern hemisphere charts show a +AO by t192 which along with the GFS model

that I spoke of goes against all guidance.

NOAA in their prognostic discussions believe the AO will remain strongly negative out as far as day

14 which is completely at odds with the model outlooks.

My punt would be that we will see big upgrades over the next two to three days with a n/easterly

airflow developing and the low over Scandinavia dropping south.

Very cold (ice days) and plenty of snow showers with pressure then building more over Greenland

and a more n/ne airflow to continue the very cold and wintry spell.

Todays model outputs are just a wobble in my opinion (maybe due to lack of data I don't know)

but are nothing to be concerned about.

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Posted
  • Location: Peterborough N.Cambridgeshire
  • Location: Peterborough N.Cambridgeshire

Even the ECM northern hemisphere charts show a +AO by t192 which along with the GFS model

that I spoke of goes against all guidance.

NOAA in their prognostic discussions believe the AO will remain strongly negative out as far as day

14 which is completely at odds with the model outlooks.

My punt would be that we will see big upgrades over the next two to three days with a n/easterly

airflow developing and the low over Scandinavia dropping south.

Very cold (ice days) and plenty of snow showers with pressure then building more over Greenland

and a more n/ne airflow to continue the very cold and wintry spell.

Todays model outputs are just a wobble in my opinion (maybe due to lack of data I don't know)

but are nothing to be concerned about.

]

Good post there mate.

I must admit I think I over reacted earlier. I remember back to what happened prior to our recent cold spell and how the models had a 24hr wobble before returning to normal. At the moment I don't think any of the models have this correct especially in the medium range so its a case of being patient and probably just focussing on the track of this LP.

I will finally add that I just watched a BBC forecast saying "turning very wintry late next week". This is very unusual for the BBC to go this far so they must be fairly confident.

Edited by THE EYE IN THE SKY
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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

Remaining cold or very cold in the northern half of the country as we approach new year it seems, with colder conditions setting up over southern parts as we head into next week but the significant cold staying furthernorth. The 528 dam line seems to want to straddle the centre of the country yoyoing around the midland and north england, where it positions itself is indicative of where the polar front is lying, areas north of it will most likely see snow down to low levels especially the further north you are from it, areas on or close to it will see marginal conditions, the further south from it higher likelihood of rain.

General theme is for blocking to remain high over Greenland and for the atlantic to try to make inroads from the SW but failing miserably, the new year period looks to be dominated by a northerly to easterly flow, plenty of frost in the north and potential for heavy snow showers in the NE spilling into central areas at times.

Its a cold outlook.

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Posted
  • Location: Hughenden Valley, Buckinghamshire.
  • Location: Hughenden Valley, Buckinghamshire.

I think many people from the West Midlands/ South Wales area would probably take short term gain over long term ambition at the moment with regards to snowfall seeing as they have had precious little from this cold spell. Certainly where I am at the moment for Christmas (gloucester) would benefit from this short term thinking. It is easy to talk about the long term when your area has had snowfall on the ground and ice days etc but for areas where this has not been the case you can understand the view of take what you can for the short term and leave the long term as just that!

well said kev! i want an extended cold spell just like anyone else but the possibility of getting a dumping of snow in s/w midlands next week is an amazing thing! try and put yourselves in our shoes! i have had a snow shower 1 cm and a snowy band the other day that left 2 cm's! i dont think sme peeps here are being fair saying we r being selfish wanting lots of snow on tuesday more than a prolonged cold spell!

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Posted
  • Location: South Yorkshire Barnsley 66m ASL
  • Location: South Yorkshire Barnsley 66m ASL

Even the ECM northern hemisphere charts show a +AO by t192 which along with the GFS model

that I spoke of goes against all guidance.

NOAA in their prognostic discussions believe the AO will remain strongly negative out as far as day

14 which is completely at odds with the model outlooks.

My punt would be that we will see big upgrades over the next two to three days with a n/easterly

airflow developing and the low over Scandinavia dropping south.

Very cold (ice days) and plenty of snow showers with pressure then building more over Greenland

and a more n/ne airflow to continue the very cold and wintry spell.

Todays model outputs are just a wobble in my opinion (maybe due to lack of data I don't know)

but are nothing to be concerned about.

The proper NE flow would in fact beat last weeks cold spell for many! so i hope you are right and love to see the other models trend towards GEM

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Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

Also, to be be totally honest, I don't think a modern winter is capable of producing a cold spell of more than 7 days or so - anywhere in England anyway. At least it hasn't in my lifetime, and I'm 27 now.

More like "anywhere in southern England". There were 13 successive days of snow cover in parts of the Midlands in February 2009, and parts of northern England are currently experiencing their 9th successive day of snow cover.

To be pedantic there was a 10 day cold spell in parts of southern (especially south-western) England as well in late December and early January 2008/09, but it did not feature much in the way of snow.

I think the longer-term outlook will continue to chop and change with time. What matters now for cold/snow lovers is that the models have all positioned the low for 28/29 December further south, allowing the cold air to head south a lot sooner and with far less uncertainty.

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Posted
  • Location: near dalmellington E ayrshire 302m asl
  • Weather Preferences: mediterranean summer
  • Location: near dalmellington E ayrshire 302m asl

im sure the the models will be missing data they seem all over the place at this point it will be monday at least before some sort consistency takes place they are not worth looking at sadly im sure the experienced model watchers already no this aggressive.gif

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

I'm reading a lot of posts talking up the GEM model, I must admit some ignorance because I tend to stick with the traditional big 3 but if others are convinced the gem should be spoken about in the same breath as the gfs/ecm and ukmo, I will gladly look at it and take it's output seriously. Anyway, a very cold spell is now odds on to begin around the middle of next week but the building blocks will be put in place during the next few days. Some people are only interested in instant gratification snowfalls but there is a lot more to cold spells than that...get the foundations in position first and worry about the finer detail later.

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Posted
  • Location: nr Guildford, surrey
  • Location: nr Guildford, surrey

I'm reading a lot of posts talking up the GEM model, I must admit some ignorance because I tend to stick with the traditional big 3 but if others are convinced the gem should be spoken about in the same breath as the gfs/ecm and ukmo, I will gladly look at it and take it's output seriously. Anyway, a very cold spell is now odds on to begin around the middle of next week but the building blocks will be put in place during the next few days. Some people are only interested in instant gratification snowfalls but there is a lot more to cold spells than that...get the foundations in position first and worry about the finer detail later.

I think it has been verifying quite well in recent times

and I agree, could live with a bit of rain if it means the cold sticks around longer in the long term

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

I think it has been verifying quite well in recent times

and I agree, could live with a bit of rain if it means the cold sticks around longer in the long term

We are lucky to have the models showing such a wintry outlook and that the less cold breakdown has only been partially successful with most of scotland still in cold air which won't be displaced before colder arctic air begins to push south across the n.isles later tomorrow and then further south on mon/tues. It wasn't too long ago that the models were showing a complete breakdown to milder weather and the backtrack has been astonishing. As for the GEM run, I agree with other comments...it's SUPERB.

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Posted
  • Location: Maidstone, Kent
  • Location: Maidstone, Kent

Likes like even the Met Office can't really call this one, i personally think it will fall as rain in the Southwest, and then snow North of the Midlands.

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Posted
  • Location: Upper Tweeddale, Scottish Borders 240m ASL
  • Location: Upper Tweeddale, Scottish Borders 240m ASL

New thread here:

Please read what I've written. I hate pressing the delete button - it's such a waste of effort on your part.

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