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Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!


Paul

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Posted
  • Location: Worcestershire/Warwickshire/North Oxfordshire
  • Location: Worcestershire/Warwickshire/North Oxfordshire

All models suffer from the over progression.

 

If this was the old GFS it wouldn't have even gone for a slider just sent it all north. 

 

UKMO was over progressive yet it came back into swing.

When the new GFS was the Parallel run it always showed the coldest snowiest charts, but none of that ever became reality.

 

I don't think we can trust the raw output of the current GFS.

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Posted
  • Location: Wellseborne, Warwickshire
  • Weather Preferences: Southerly tracking low pressure in winter. Hot and thundery in the summer
  • Location: Wellseborne, Warwickshire

Hemispherically speaking there's quite a difference comparing the 12 and the 18z at a reasonable time frame , strong hights over the polar regions really ensuring the split in the vortex is maintained , it could well be now as we move through the next wk we see the ramifications of the minor SSW begin to show its hand .

post-9095-0-86884500-1421620715_thumb.jppost-9095-0-72798000-1421620732_thumb.jp

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Obviously GFS precip amounts shouldn't be taken too seriously at this stage, especially with snow. 18Z much better for snow prospects for a wider wearer as Kold Weather said a few posts back. Here is Snow accumulation GFS(take with salt).

attachicon.gifimage.jpg attachicon.gifimage.jpg attachicon.gifimage.jpg

attachicon.gifimage.jpg attachicon.gifimage.jpg attachicon.gifimage.jpg

attachicon.gifimage.jpg attachicon.gifimage.jpg attachicon.gifimage.jpg[/quote

I'm not buying into any of these charts the Met Office are fairly confident there will be no troublesome snowfalls this week.

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Posted
  • Location: Bexleyheath (south), Kent
  • Location: Bexleyheath (south), Kent
Obviously GFS precip amounts shouldn't be taken too seriously at this stage, especially with snow. 18Z much better for snow prospects for a wider wearer as Kold Weather said a few posts back. Here is Snow accumulation GFS(take with salt).

attachicon.gifimage.jpg attachicon.gifimage.jpg attachicon.gifimage.jpg

attachicon.gifimage.jpg attachicon.gifimage.jpg attachicon.gifimage.jpg

attachicon.gifimage.jpg attachicon.gifimage.jpg attachicon.gifimage.jpg[/quote

I'm not buying into any of these charts the Met Office are fairly confident there will be no troublesome snowfalls this week.

You don't have to buy them, they're free?

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Posted
  • Location: Stroud, Gloucestershire
  • Weather Preferences: Extreme!
  • Location: Stroud, Gloucestershire

GFS high res show nicely how after the front initially pushed through from west to east we start to get a pull back as the low starts to "reshape" and becomes a cut off low and drags in a south easterly flow with the ppn moving back West. This is a feature that needs watching closely IMO. There would certainly be a higher chance of some decent snowfall for some from this type of evolution.It was tentatively mentioned in the Countryfile forecast as well.........

 

Rmgfs691.gif

GFS has plenty of PPN around from +48 through to +72 though at that range the details will change, but the cut off Low scenario is worth watching!!

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Posted
  • Location: South Croydon
  • Location: South Croydon

Hemispherically speaking there's quite a difference comparing the 12 and the 18z at a reasonable time frame , strong hights over the polar regions really ensuring the split in the vortex is maintained , it could well be now as we move through the next wk we see the ramifications of the minor SSW begin to show its hand .

attachicon.gifimage.jpgattachicon.gifimage.jpg

Hemispherically speaking there's quite a difference comparing the 12 and the 18z at a reasonable time frame , strong hights over the polar regions really ensuring the split in the vortex is maintained , it could well be now as we move through the next wk we see the ramifications of the minor SSW begin to show its hand .

attachicon.gifimage.jpgattachicon.gifimage.jpg

Isn't it a little early for the warming to have an effect on the trop? I was reading an academic paper the other day that these take from 2 weeks to 2 months.

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Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

How did the 18z pan out for the end of week onwards... Should I draw my own conclusions as no posts have been made.

An easterly all the way from kamchatka....

 

BFTP

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Posted
  • Location: Emsworth, Hampshire
  • Location: Emsworth, Hampshire

im not to sure it is to progresive all todays models and yesterdays also show a breakdown by the end of the week

Sorry, I should of been more clear. I was just speaking of the GFS over the last couple of days.

Edited by SnowMania
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Posted
  • Location: Headington,Oxfordshire
  • Weather Preferences: Snow
  • Location: Headington,Oxfordshire

GFS high res show nicely how after the front initially pushed through from west to east we start to get a pull back as the low starts to "reshape" and becomes a cut off low and drags in a south easterly flow with the ppn moving back West. This is a feature that needs watching closely IMO. There would certainly be a higher chance of some decent snowfall for some from this type of evolution.It was tentatively mentioned in the Countryfile forecast as well.........

Rmgfs691.gif

GFS has plenty of PPN around from +48 through to +72 though at that range the details will change, but the cut off Low scenario is worth watching!!

So very true, Kold mentioned this as it came out. If you look at my earlier post as the system moves back westward look at the Snow depth go up( pinch of salt on amounts), as you say interesting one to watch with both ECM showing something similar. Edited by Mark N
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Posted
  • Location: Orpington Kent.
  • Location: Orpington Kent.

An easterly all the way from kamchatka....

 

BFTP

Sorry for inquiring.. I should have mentioned was on phone traveling.. I shall stick with my original thoughts then ;)

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Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

Sorry for inquiring.. I should have mentioned was on phone traveling.. I shall stick with my original thoughts then ;)

Similar sort of theme thus far but slightly increased snow chances for middle of week.  We more or less know the theme for next week and just detail alters

 

BFTP  

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

Now we are homing in on the Slider I would say the following counties are probably already out of the game

 

Suffolk, Norfolk, Lincs, Yorkshire (E ), Northumberland,Tyne & Wear, east Lothian-

 

On the cusp ( obviously eastern portions )

 

Kent,Essex,Cambridgeshire & Rutland...

 

S

Just wanted to highlight the above again because in my opinion this is spot on. I said a few days ago that in these situations the fronts do not make it as far as my location and this could well be the case again. At the moment im not expecting the snow to get any further E than say around Leicester.

 

Beyond potential snowfall this week and I still cannot see a return of milder weather infact so far the 18Z remains cold especially towards the E.

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Posted
  • Location: Wellseborne, Warwickshire
  • Weather Preferences: Southerly tracking low pressure in winter. Hot and thundery in the summer
  • Location: Wellseborne, Warwickshire

Isn't it a little early for the warming to have an effect on the trop? I was reading an academic paper the other day that these take from 2 weeks to 2 months.

It really depends , u can have a quick trop response almost immediately on occasion , the warming of jan 2013 saw a quick response of about 5/6 days , but I would normally say about 20+ days on avarage .

Edited by Severe Siberian icy blast
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Posted
  • Location: sheffield
  • Weather Preferences: cold ,snow
  • Location: sheffield

Not sure ive seen so many ridges and fronts which all distrupt? High pressure over europe on the 18z for sure!!!

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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

Definitely a consensus being met with the first set of fronts stalling and sliding away south.

This backed up by the JMA

J84-21.GIF?18-18

Cold too by Thursday

J84-7.GIF?18-18

 

Chance of wintry showers into parts of the East by Thursday, this suggested by the week ahead forecasts and the Thursday  FAX chart.

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Posted
  • Location: Evesham/ Tewkesbury
  • Weather Preferences: Enjoy the weather, you can't take it with you 😎
  • Location: Evesham/ Tewkesbury

I think the problematic forecast for Tuesday tonight shows that forecasting snow in this country is about as hard as it gets.! Latest thoughts from the models show a band of precip slowly moving in from the West on Tuesday and emphasis on slowly. As you would expect something a little milder moving in and if the models are correct, mainly a wintry mix on high ground over the west, cold rain for lowland areas. Dewpoints and 850,s are really not conducive for snow to fall especially on low ground.  Perhaps if that front moves further east and keeps itself togeather then ie east midlands may well see some snow, as it engages with some deeper cold. All up for grabs, but at the moment, a non event for snow come Tuesday for "most" :closedeyes:  :nonono:  :lazy:

post-6830-0-30595300-1421622238_thumb.gi

post-6830-0-69236200-1421622306_thumb.pn

post-6830-0-75334000-1421622348_thumb.pn

post-6830-0-08084300-1421622392_thumb.pn

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Posted
  • Location: Burton-on-Trent (90m), Larnaka most Augusts
  • Location: Burton-on-Trent (90m), Larnaka most Augusts

Isn't it a little early for the warming to have an effect on the trop? I was reading an academic paper the other day that these take from 2 weeks to 2 months.

 

Depends, I think with an easterly QBO the downwelling is much quicker. Usually the first response takes 10-15 days.

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Posted
  • Location: Headington,Oxfordshire
  • Weather Preferences: Snow
  • Location: Headington,Oxfordshire

JMa 18z looks good for Wed Snow I'd say. Cold uppers in place. Still a lot of precip around.

post-15543-0-96631800-1421622524_thumb.j post-15543-0-96663800-1421622545_thumb.j post-15543-0-40991200-1421622566_thumb.j 1am

post-15543-0-71565400-1421622633_thumb.j post-15543-0-62552200-1421622645_thumb.j post-15543-0-60054900-1421622654_thumb.j 7am

post-15543-0-45513200-1421622686_thumb.j post-15543-0-25829800-1421622699_thumb.j post-15543-0-38136900-1421622718_thumb.j 1pm

post-15543-0-53040400-1421622758_thumb.j post-15543-0-81824800-1421622805_thumb.j post-15543-0-34655600-1421622819_thumb.j 7pm

Not one to post the JMA often but good to see similar evolution to both ECM/GFS

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Posted
  • Location: Wellseborne, Warwickshire
  • Weather Preferences: Southerly tracking low pressure in winter. Hot and thundery in the summer
  • Location: Wellseborne, Warwickshire

I think the problematic forecast for Tuesday tonight shows that forecasting snow in this country is about as hard as it gets.! Latest thoughts from the models show a band of precip slowly moving in from the West on Tuesday and emphasis on slowly. As you would expect something a little milder moving in and if the models are correct, mainly a wintry mix on high ground over the west, cold rain for lowland areas. Dewpoints and 850,s are really not conducive for snow to fall especially on low ground.  Perhaps if that front moves further east and keeps itself togeather then ie east midlands may well see some snow, as it engages with some deeper cold. All up for grabs, but at the moment, a non event for snow come Tuesday for "most" :closedeyes:  :nonono:  :lazy:

Quite confusing as your using old data , ecm and the 18z give a good snow event for many central areas , with Ian hinting the meto may well put warnings out tomorrow .

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Posted
  • Location: Evesham/ Tewkesbury
  • Weather Preferences: Enjoy the weather, you can't take it with you 😎
  • Location: Evesham/ Tewkesbury

Quite confusing as your using old data , ecm and the 18z give a good snow event for many central areas , with Ian hinting the meto may well put warnings out tomorrow .

It all depends how fast that front moves in =To fast, we get mainly cold rain =Slower then its likely to be more wintry, although that  depends on how the front reacts with the colder conditions further east. It may well just fizzle out as Ive often seen. :sorry:

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Posted
  • Location: Gillingham, Kent
  • Weather Preferences: Snow, Thunderstorms,
  • Location: Gillingham, Kent

Steve. Could you clarify what you mean by "mixing zone" please?

 

Less cold air mixing out the cold air - Likely to be rain in that zone

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