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Model Output Discussions 18z 31/01/2016


phil nw.

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

Had a minor fit when looking at the various options on the table for the weekend; I've got to produce some kind of forecast from that! :80:

GFS appears to be the absolute worst case scenario in which LP develops vigorously while still SW of the UK and then tracks right through England. Largely a rain event for many areas with the thrust of milder air dominating the precipitation mode.

ICON/DWD offers a variant that takes the low along the Channel with heavy rain during the morning for the south transitioning to increasingly light snow by Saturday evening.

ECM is essentially a version of the GFS scenario in which the low is slower and weaker but follows a similar path. Snow possible somewhere in the middle third of the UK. The following NE flow overnight Sun/Mon looks cold and unstable enough to produce some snow showers for eastern parts of England.

ARPEGE (shown below-left) keeps the weekend low weak and tracking through the Channel. This produces a marginal rain/snow mix for the far south, with the frontal system not making it to areas further north. It needed more development of the feature moving through the Channel on Friday to setup the level of cold undercut for a proper snow event.

For this, UKMO stands out in this respect, with LP SE of the UK by noon Saturday (below-middle) which is either the Friday feature or the second feature moving especially fast and without much development. Either way, it sets up a good movement of cold air to the UK from the east for Sunday which makes for a promising looking +120 chart (below-right).

arpegeeur-0-84.png?12  UW72-21.GIF  UW96-21.GIF?10-18 

So yeah, this sets me up for perhaps the most uncertain 4-5 day forecast imaginable. Thanks, models!

 

Looking further ahead, ARPEGE shows the potential for embedded features on Mon that stand a good chance of falling as snow:

arpegeuk-1-114-0.png?10-18

 

 

...and then we get to the possible disruption of that major trough in the Atlantic which GFS does interesting things with tonight.

The critical period for which way things go appears to be around +120;

ecmt850.120.png h850t850eu.png 

That secondary low/shortwave just exiting Newfoundland on the ECM run (left) runs NE and this allows the trough to keep advancing NE even as the diving jet starts to influence the base of it. So we're left looking to the next incoming trough to swing down south of the old trough, which the model does to fairly well to be fair.

Without that secondary feature, the door is wide open for high pressure across Svalbard to have some influence on our weather. That wouldn't be bad going for the 'intermission' ahead of the end-month HLB pattern that has gained support today now that ECM has adjusted to a more amplified MJO propagation. Shame UKMO has that feature just like ECM and is also a bit more progressive :nea:but I forgive it after the wonders it has performed with the weekend setup!

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Just looking at the ECM - whilst at first glance it isnt go great in terms of cold & there is no pronounced upper high over scandi after 168- there is a shift towards the GFS solution-

-again referring to the 240 charts then the 216 of yesterday - now the 192- through 240 today the easterly vector of that huge low has been replaced with a southerly component -& as a result that low that was progged to blast all tge way to Norway is now progges to sink south....

expect more swings to cold in the mid term - & some more refinement over the sliders for Sat

my best punt has moved away from central wales to the staffordshire morelands....

 

s

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Posted
  • Location: Grimsby, North East Lincolnshire 16m asl
  • Location: Grimsby, North East Lincolnshire 16m asl
3 minutes ago, cyclonic happiness said:

I'm so , so very tired. we have had to put up with rubbish for 3 years now.  I don't care how old anyone is, everyone I've spoken to around here, even people in their 80s, have not seen a period so devoid of snow.

I'm so tired of the models whipping everything away from us at the last minute. the more 'clever' people on here will say I'm being silly and that I should not look beyond such and such a period. but I don't think anything has ever ben as misleading as it has been these past 2-3 years. Have the models become less reliable or has the weather? We really need to ask this question!

 

3 minutes ago, cyclonic happiness said:

I'm so , so very tired. we have had to put up with rubbish for 3 years now.  I don't care how old anyone is, everyone I've spoken to around here, even people in their 80s, have not seen a period so devoid of snow.

I'm so tired of the models whipping everything away from us at the last minute. the more 'clever' people on here will say I'm being silly and that I should not look beyond such and such a period. but I don't think anything has ever ben as misleading as it has been these past 2-3 years. Have the models become less reliable or has the weather? We really need to ask this question!

I agree mate. It's no coincidence in my opinion that the brutal cold that has affected the north eastern states over the past three years has something to do with our winters as this has super charged the jet stream. I can remember watching an old Bec forecast during February 1991. The states were having an unusual warm spell while we were getting hammered with snow and sub zero temperatures. 

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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 don't understand all the moaning in our current position with a colder spell and at least a chance of snow during the coming weekend and into next week. Last week there was no sign of a colder spell which is why lots of towels, including my own were being hurled in disgust but things are now looking better for coldies. Next week isn't resolved, it could stay cold as per gfs with a snowy midweek followed by crisp frosty conditions...winter is coming back to life in my opinion!:)

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Posted
  • Location: Home: Chingford, London (NE). Work: London (C)
  • Weather Preferences: Winter: cold and snowy. Summer: hot and sunny
  • Location: Home: Chingford, London (NE). Work: London (C)
8 minutes ago, cyclonic happiness said:

I'm so , so very tired. we have had to put up with rubbish for 3 years now.  I don't care how old anyone is, everyone I've spoken to around here, even people in their 80s, have not seen a period so devoid of snow.

I'm so tired of the models whipping everything away from us at the last minute. the more 'clever' people on here will say I'm being silly and that I should not look beyond such and such a period. but I don't think anything has ever ben as misleading as it has been these past 2-3 years. Have the models become less reliable or has the weather? We really need to ask this question!

It has been a terrible 3 years for snow for the vast majority of the U.K. It's strange, as the previous 4 winters - 2008/09 right up to 2012/13 - all delivered at least one good snow event for here, and most of the country. 

There have been snowless winters in the past, but I can't personally remember in my 30 years of life there being 3 almost snowless winters in a row. 

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

Well I'm going to stick my neck out - i believe there will be snow for many on Sunday. I don't care what the GFS precip charts say - i cannot see that sharp NEly in low heights being devoid of precipitation, and I believe it will be -6C 850s by then. The modelled situation for Sunday has been consistent for days so high certainty that the general set-up will happen. Sunday's the day. White stuff for 50% of England on that day (Wales/Scotland will probably have seen snow before then)

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
7 minutes ago, Man With Beard said:

Well I'm going to stick my neck out - i believe there will be snow for many on Sunday. I don't care what the GFS precip charts say - i cannot see that sharp NEly in low heights being devoid of precipitation, and I believe it will be -6C 850s by then. The modelled situation for Sunday has been consistent for days so high certainty that the general set-up will happen. Sunday's the day. White stuff for 50% of England on that day (Wales/Scotland will probably have seen snow before then)

I'm sure that many will, MWB...But, my guess is that folks (like me) who live within 30 miles of either the east or south coast will be very lucky to see sleet?:)

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

Unfortunately, the ECM ens at 240 are a complete disaster, with the majority favouring as zonal westerly regime as you could ever imagine.

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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough
29 minutes ago, Man With Beard said:

Well I'm going to stick my neck out - i believe there will be snow for many on Sunday. I don't care what the GFS precip charts say - i cannot see that sharp NEly in low heights being devoid of precipitation, and I believe it will be -6C 850s by then. The modelled situation for Sunday has been consistent for days so high certainty that the general set-up will happen. Sunday's the day. White stuff for 50% of England on that day (Wales/Scotland will probably have seen snow before then)

For the Midlands southwards I would say there will be a window between Sunday afternoon and Tuesday morning where there could be potential for either back edge snow from the clearing weather system or showers pushing in from the north sea.

Mean 850s from Saturday to Tuesday

EDU0-72.GIF?10-0 EDU0-96.GIF?10-0 EDU0-120.GIF?10-0 EDU0-144.GIF?10-0

Further north the risk is there from Saturday onwards with eastern Scotland and north east England particularly at risk of a spell of a few days where snow showers could push in.

Beyond this there still remains mixed signals on the approaching Atlantic system and whether we can develop a pattern to our east which is feasible to sustain cold weather over the UK. Ultimately we need heights over Scandinavia with the trough becoming cut off over central/southern Europe. We do not want to see that trough too far north as it could allow the Atlantic to push through the UK or be too weak and south which would allow heights to settle too far south to bring any cold continental air into the UK.

Edited by Captain Shortwave
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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
3 minutes ago, feb1991blizzard said:

Unfortunately, the ECM ens at 240 are a complete disaster, with the majority favouring as zonal westerly regime as you could ever imagine.

Can you view the individual members? The updated debilt ensembles don't look too bad to me. Control run looks interesting.

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
1 minute ago, blizzard81 said:

Can you view the individual members? The updated debilt ensembles don't look too bad to me. Control run looks interesting.

No but its a much smaller cluster that favours cold, a much larger one that favours zonal.

EDIT : Although my info is third party info from the USA so I hope your right.

Edited by feb1991blizzard
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Posted
  • Location: Sandbach
  • Location: Sandbach
1 minute ago, blizzard81 said:
9 minutes ago, feb1991blizzard said:

Unfortunately, the ECM ens at 240 are a complete disaster, with the majority favouring as zonal westerly regime as you could ever imagine.

Can you view the individual members? The updated debilt ensembles don't look too bad to me. Control run looks interesting.

as if a 240 ever verifies

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .
13 minutes ago, feb1991blizzard said:

Unfortunately, the ECM ens at 240 are a complete disaster, with the majority favouring as zonal westerly regime as you could ever imagine.

I thought this ECM ensemble spread looked interesting at T192hrs:

EEH1-192.thumb.gif.9adeeb5094832827ebe84gfsnh-0-192.thumb.png.efc35abb6ca805b36d

Spread to the west displaced Azores high, spread to the ne Scandi high and a comparison of the GFS operational run at T192hrs you can see the similarities.

 

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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
9 minutes ago, Tim Brawn said:

as if a 240 ever verifies

The Ecm 12z op finished cold with wintry showers with potential for further cold NWly outbreaks further ahead..and I'm looking forward to this colder phase, simply because most of this winter has been so hideously mild!:)

 

ecmt850.096.png

ecmt850.120.png

ecmt850.240.png

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
22 minutes ago, nick sussex said:

I thought this ECM ensemble spread looked interesting at T192hrs:

EEH1-192.thumb.gif.9adeeb5094832827ebe84gfsnh-0-192.thumb.png.efc35abb6ca805b36d

Spread to the west displaced Azores high, spread to the ne Scandi high and a comparison of the GFS operational run at T192hrs you can see the similarities.

 

The spread might be good Nick but it could just be 1 or 2 members. Don't shoot the messenger, I hope its BS tbh, the only things I can actually offer as back up right now are these.

eps_pluim_tt_06260.png

Reem2401.gif

 

You can see on the graph that D10 mean max temps of 6c  and mins of 3c in a location that would be better for lower temps should there be trough disruption and a low dive SE

Edited by feb1991blizzard
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Posted
  • Location: Nr Chelmsford, Essex
  • Weather Preferences: Hurricanes, Thunderstorms and blizzards please!
  • Location: Nr Chelmsford, Essex

 

26 minutes ago, nick sussex said:

I thought this ECM ensemble spread looked interesting at T192hrs:

EEH1-192.thumb.gif.9adeeb5094832827ebe84gfsnh-0-192.thumb.png.efc35abb6ca805b36d

Spread to the west displaced Azores high, spread to the ne Scandi high and a comparison of the GFS operational run at T192hrs you can see the similarities.

 

Yes, this does look interesting and provides plenty of reasons for optimism for the rest of February.  However, the big question is Nick, what is the Sussex 'Optimism-meter' registering at the moment?

Edited by Ice Day
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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks
39 minutes ago, feb1991blizzard said:

No but its a much smaller cluster that favours cold, a much larger one that favours zonal.

EDIT : Although my info is third party info from the USA so I hope your right.

The anomaly charts are nothing like that for 500mb so unlikely, other than if 240h coincided with a deep surface low approaching, that they would be zonal and then only temporarily. 

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .
6 minutes ago, Ice Day said:

 

Yes, this does look interesting and provides plenty of reasons for optimism for the rest of February.  However, the big question is Nick, what is the Sussex 'Optimism-meter' registering at the moment?

Lol! Well the op meter met a grisly end after a poor set of outputs a few weeks back! Is this optimism as in desperate hope or gritty realism?

I liked the GFS but not so much the ECM past T144hrs. Reading the NCEP update theres now a lot of uncertainty with the pattern there and the development of a possible low running up the ne of the USA this will effect the displaced Azores high and also energy spilling east towards the troughing to the nw of the UK.

 

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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
On 8 February 2016 at 10:07 AM, Singularity said:

h850t850eu.png

Deeper low for Friday more than compensates for stronger HP wedge. Snow line for midday Friday is Bristol northward on this run but on track to move back south as LP moves to SE. The 00z had the boundary right along the south coast - as was the N. limit of the precipitation.

Funny how you can have so much potential within 4-5 days yet so little confidence in getting anything much out of it, almost entirely down to a single model (inc. its ens.).

Waiting now to see how the weekend pans out on the 06z as that's when the real fun and games happened on the 00z and 18z. Then my dabble in frame-by-frame model watching will be over for 6 hours or so :). Basically doing this for a change of theme having focused so much on the longer range of late.

 

I would say that although we are all just trying to trend spot here , lets first get the weekend sorted out before trying to guess what comes next week .

the biggest hint for me regarding next week is the trough disruption , it's more than plausible giving the high pressure developing toward Iceland these next 4 days , given the fact that the jets diving south into Europe then for me once we get cold air in place over scandi/Europe then we have the ingredients for a potential easterly . I know lots of things need to fall in place but on the face of it we have all the ingredients .

southerly jet 

high pressure building north of uk 

cold air in place (by then) 

Also re the ensembles I think that they could well be lagging behind the op , the ECM isn't what it was pre 2012 , i no peeps can't remember an 'upgrade' but I specifically remember it undergoing one just before the famous Dec 2012 epic fail . 

Watch this space I think . Not saying it's gonna happen , damn we'v been there before but definately one to watch .

 

 

Edited by Severe Siberian icy blast
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Posted
  • Location: Bristol/South East
  • Location: Bristol/South East
1 minute ago, nick sussex said:

Lol! Well the op meter met a grisly end after a poor set of outputs a few weeks back! Is this optimism as in desperate hope or gritty realism?

I liked the GFS but not so much the ECM past T144hrs. Reading the NCEP update theres now a lot of uncertainty with the pattern there and the development of a possible low running up the ne of the USA this will effect the displaced Azores high and also energy spilling east towards the troughing to the nw of the UK.

 

Would that give us a potential shot at cold? About time the Azores high got shafted 

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
7 minutes ago, johnholmes said:

The anomaly charts are nothing like that for 500mb so unlikely, other than if 240h coincided with a deep surface low approaching, that they would be zonal and then only temporarily. 

So its a false alarm then?

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .
1 minute ago, wishingforsnow said:

Would that give us a potential shot at cold? About time the Azores high got shafted

You want the Azores high to displace as far nw as possible and amplify as this will help to sharpen up the troughing to the nw. Its a bit of a battle though because the PV associated with that troughing is desperately trying to flatten things.

Although the ECM wasn't terrible in that it does keep the Azores high displaced theres no trough disruption on that like the GFS.

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