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Model Output Discussion - 7th-13th November


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Posted
  • Location: Brighton (currently)
  • Location: Brighton (currently)

Well I've looked at the 12z and yes again it shows a change ahead. What it doesn't show is a jet north. Folk should have a look at the jet forecast in the datacentre...it is subject to change for sure like the models BUT it doesn't show the jet north of the UK throughout the run, indeed it solidifies to run generally along latitude southern half of UK dipping SE wards into Europe. Any talk of the jet being north looking at the 12z run is erroneous, we would defo get interesting weather with that run, the kitchen sink. Plenty to play for ahead and no reason to be down beat at all...plenty can, and looking at the outlook, will happen.

BFTP

Are you only refering to the GFS? Have a look at the ECM and tell me where the jet is!

Karyo

Edited by karyo
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Posted
  • Location: Truro, Cornwall
  • Weather Preferences: Winter - Heavy Snow Summer - Hot with Night time Thunderstorms
  • Location: Truro, Cornwall

The 12z GFS Ensembles to me really dont support the much cooler conditions after this week. The Aberdeen ensembles on the operational is a huge outlier towards the end with the rest much more supportive of high pressure. The 850hPa temperatures also are pretty much a cold outlier towards the end too. I did have my doubts on this run as it seems so different to the rest. Who knows maybe it is actually on to something but many factors are against cold weather right now.

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Posted · Hidden by Paul, November 13, 2011 - Please stop the personal comments.
Hidden by Paul, November 13, 2011 - Please stop the personal comments.

the 6z was awful nick, we will have to agree to disagree on this one, still lots of changes to come before the atlantic lows are due to push through the uk next weekend.

with all due respect frosty if you think for cold 12z gfs is anything other than awful you need to honestly go back to the drawing board .

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Posted
  • Location: Aviemore
  • Location: Aviemore

There's been an alarming increase in sniping and personal comments in the thread today. Can I make a request to everyone reading/taking part in this thread - if you see a post that is out of line please click the report button and let us know.

We'll really appreciate the help as it'll allow us to be much quicker to get on top of any potential problems, and this thread will then be a far better place.

Thanks

Paul

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Posted
  • Location: Bournemouth
  • Weather Preferences: Snow. Winter. Dry cool Summers
  • Location: Bournemouth

Yes the models are poor if you like cold.

However things can change quickly and watching the weather on country file, they had little confidence in what the forecast was for Friday which to my mind says why look any further until the pattern is established.

Edited by Paul
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Posted
  • Location: Bearsden, East Dunbartonshire
  • Location: Bearsden, East Dunbartonshire

There's been an alarming increase in sniping and personal comments in the thread today. Can I make a request to everyone reading/taking part in this thread - if you see a post that is out of line please click the report button and let us know.

We'll really appreciate the help as it'll allow us to be much quicker to get on top of any potential problems, and this thread will then be a far better place.

Thanks

Paul

Probably the extreme frustration of those watching the models (including me). And of course conflicting opinions and preferences with people wanting cold and snow and those enjoying the more abundant summer like charts (pitty it's November isn't). I think I would like to give model watching a break but because it's so stressful you can't keep your eye of it. Really, people just need to calm down and be thankful that it's mid November and not Mid January. I'm sure we will have our moments this winter but I think I'm ready to take a break from model watching with the dull output and return at the end of the month to see what's going on and to start my winter blog (hoping to get a decent diary of snow this year again).

Looking at the end of the GFS run, there is a slight improvement than of late but realisticly it could be better and realisticly having charts without snow in Autumn isn't rare. I just hope that our pattern evolves into something more cold and snowy further down the line (hopefully during a pattern change in December).

What are people's thoughts on what could follow in December with a change in pattern as people are talking about a possibe Bartlett scenario and could this result in cold and snow suceeding that period. With such a deprivation of cold this autumn, surely it can't last for all of December let alone January. And can someone elaborate on how current stratospheric conditions may not be good for the winter (in my opinion I can't see a Bartlett Dominated December be followed by a snowless January and Febuary)...

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Posted
  • Location: Carlisle, Cumbria
  • Weather Preferences: Atlantic storms, severe gales, blowing snow and frost :)
  • Location: Carlisle, Cumbria

GFS 18z so far looks like a continuation of previous runs with the Atlantic gathering it's troops ready for the assault, low pressure stretched right across Northern Europe and a strengthening Polar vortex kicking things off in the Atlantic with the jet stream poised to cut right through the UK aliened west to east.

I would think we are heading for a very mobile pattern change, which isn't a bad thing and I'd welcome this.

Edited by Liam J
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Posted
  • Location: Bearsden, East Dunbartonshire
  • Location: Bearsden, East Dunbartonshire

GFS 18z so far looks like a continuation of previous runs with the Atlantic gathering it's troops ready for the assault.

I assume it's better to have an onslaught of Atlantic Weather now rather than during mid winter. Remember 09/10, signficant cold can follow Atlantic dominated periods.

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

Reliable timeframe remains about 96 hours - lots of uncertainty beyond as the models don't have a definate handle on events thereafter - GFS as expected wants to usher in the atlantic - GFS default position is always to bring in the atlantic, ECM keen on maintaining strong heights to our east.. ECM does tend to perform much better than GFS when we have blocking over europe, however, GFS is better with developments to our NW and W.

As I said yesterday I'm non-the wiser at to how events may pan out.

Temperatures for the foreseeable future look mild, though not on the scale of recent days, so it will feel a bit more like late autumn rather than early autumn.

I'm tempted to refrain from model watching until the weekend as I expect lots of tooing and froing from the models in the coming days - with no clear trend as we approach the end of the month. Indeed I am going to test myself and not look at any of the models or this forum until friday evening at the earliest - hopefully we will have a clear pattern change by then, an atlantic assault will do me just fine at least it will bring some variety and none of the monotous weather of the last 3 weeks.

Interesting to note Meto expect some snow for northern high ground by the 20th - suggesting the trough will get far enough east to deliver some polar maritime air to northern parts - at long last we may loose the sub 548 dam air.. and the weather may get a bit more interesting...

Edited by damianslaw
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Posted
  • Location: Bearsden, East Dunbartonshire
  • Location: Bearsden, East Dunbartonshire

Reliable timeframe remains about 96 hours - lots of uncertainty beyond as the models don't have a definate handle on events thereafter - GFS as expected wants to usher in the atlantic - GFS default position is always to bring in the atlantic, ECM keen on maintaining strong heights to our east.. ECM does tend to perform much better than GFS when we have blocking over europe, however, GFS is better with developments to our NW and W.

As I said yesterday I'm non-the wiser at to how events may pan out.

Temperatures for the foreseeable future look mild, though not on the scale of recent days, so it will feel a bit more like late autumn rather than early autumn.

I'm tempted to refrain from model watching until the weekend as I expect lots of tooing and froing from the models in the coming days - with no clear trend as we approach the end of the month.

Interesting to note Meto expect some snow for northern high ground by the 20th - suggesting the trough will get far enough east to deliver some polar maritime air to northern parts - at long last we may loose the sub 548 dam air.. and the weather may get a bit more interesting...

We can benefit from polar martitime airstreams but I think it's too early in the season to rely on this.

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Posted
  • Location: Carlisle, Cumbria
  • Weather Preferences: Atlantic storms, severe gales, blowing snow and frost :)
  • Location: Carlisle, Cumbria

Wonderful another Euro high building back on the 18z, deep in FI though but it would bring a return of Southerly winds dragging warm air up from Europe - yuk

In the meantime the Atlantic looks like it means business in the medium term, hopefully this will be continued on future runs.

Edited by Liam J
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Posted
  • Location: Bearsden, East Dunbartonshire
  • Location: Bearsden, East Dunbartonshire

Wonderful another Euro high building back on the 18z, deep in FI though but it would bring a return of Southerly winds dragging warm air up from Europe - yuk

In the meantime the Atlantic looks like it means business in the medium term, hopefully this will be continued on future runs.

Another Euro High!!!!!!! Oh no, that's just brilliant. This can't be possible for this pattern to persist for so long and it's going to confuse our already confused envoironment and nature even more. I suppose that Euro High could move over to Greenland but another Euro High is just ironic!!!

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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

A maddening 18z tonight, cold flooding into the mid atlantic, a big freeze about 500-750 miles east of the uk but for the uk itself, a bartlett raising it's ugly head later in FI. Apart from that it turns into an unsettled run from later in the week ahead and lasts around a week or so with the heaviest rain and strongest winds in the north of the uk but some rain and windy but mostly mild weather for other areas too, the occasional burst of polar maritime air but blink or miss it and then the dreaded B word, the models continue to frustrate most of the time.

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

Another Euro High!!!!!!! Oh no, that's just brilliant. This can't be possible for this pattern to persist for so long and it's going to confuse our already confused envoironment and nature even more.

Funnily enough RJS mentioned in his LRF that during Dec there'll be talk of the weather not knowing what it wants to do. Maybe the GFS is looking plausible???

BFTP

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

Generally model reliability goes up in zonal patterns and once the models settle into that it does become increasingly frustrating if you're looking for colder conditions.

As you can see the GFS is consistent with the pattern, low pressure to the north, high pressure to the south, the variable you do get is how far north the Euro ridge heads, there is very good support across all the models for the NH pattern.

http://www.meteo.psu.edu/~gadomski/ECMWF_12z/hgtcomp.html

The mean height comparisons are in good agreement, just a little variance with the Euro ridge in Europe, if you look to the USA you can see the jet is totally flat right the way out into the Pacific, theres nothing there to interrupt the flow and until we see changes upstream with much more amplification then its a case of moving from the recent Euro ridge/ trough to the west stalemate to Euro ridge to the south/troughing to the north stalemate.

I think we're just going to have to accept that the model output is going to be rather testing for a while. This pattern is by no means unusual especially in the Autumn, its not the pattern thats really the problem its how many of us panic at this given some of the entrenched mild zonal spells we saw especially in that run of dire winters before recent colder ones.

The panic tends to ensue at the fear that this might lock in for quite a while, I'm sure if we had a crystal ball and could say two weeks and there would be a change then there would be great relief in here!

So for the timebeing it's a case of sitting and hoping that we'll see some changes as we head towards the end of the month.

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

A maddening 18z tonight, cold flooding into the mid atlantic, a big freeze about 500-750 miles east of the uk but for the uk itself, a bartlett raising it's ugly head later in FI. Apart from that it turns into an unsettled run from later in the week ahead and lasts around a week or so with the heaviest rain and strongest winds in the north of the uk but some rain and windy but mostly mild weather for other areas too, the occasional burst of polar maritime air but blink or miss it and then the dreaded B word, the models continue to frustrate most of the time.

My advice is to ignore anything the models are showing beyong the 96 hrs timeframe - no point in beating yourself up at charts being shown for 2 weeks ahead - you'll just turn into a nervous wreck. Indeed this is sound advice for anyone.

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Posted
  • Location: Thornaby-on-Tees
  • Weather Preferences: Snow Showers, Snowy Periods , Blizzards, Cold Weather
  • Location: Thornaby-on-Tees

Funnily enough RJS mentioned in his LRF that during Dec there'll be talk of the weather not knowing what it wants to do. Maybe the GFS is looking plausible???

BFTP

Don't say that BFTP I actually fancy a nice cold shot late Nov / Early Dec with some snow :')

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Posted
  • Location: Abingdon - 55m ASL - Capital of The Central Southern England Corridor of Winter Convectionlessness
  • Weather Preferences: Winter: Snow>Freezing Fog; Summer: Sun>Daytime Storms
  • Location: Abingdon - 55m ASL - Capital of The Central Southern England Corridor of Winter Convectionlessness

TWS' prediction that the late autumn warmth/dryness would persist for the majority of November has been borne out so far: http://www.netweathe...e=monthly;sess=

As a rule of thumb, the longer a pressure pattern has been knocking around, the more likely a change to a different pattern is overdue. This is anticipated by the long range forecast: http://www.netweathe...longrange;sess=

Echoing the thoughts of others, November snow should be seen as a bonus, rather than an expectation (albeit that a dusting was all that was received here last November, but welcomed nonetheless). I'd settle for a pattern change bringing cold air into Europe rather than a short-lived high ground only UK snowfall that fails to lead to an established cold pool of air on the nearby continent. Applying the principle of looking for cold first and synoptics afterwards, I believe this would be a better outcome in the longer run.

GP's preliminary winter forecast webcast type thingy I saw earlier this month suggested that February would herald the best opportunity for seasonal winter weather, however, as this is at the back-edge of the forecast period and heeding the caveats about conflicting signals and low confidence, events in the preceding months could easily skew this element of the forecast off course.

Edited by The Enforcer
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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
Why do we seem to always have the cold weather in the Atlantic and in Europe and anywhere other than us?

That's just the way the cookie crumbles, the uk got lucky last november with the late nov freeze but no chance of a repeat this time, a few minor polar maritime incursions is about the best we can hope for until sometime in december, if the mild looking high on the 18z pushes into the uk it will wipe out the first few weeks of winter very easily.

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Posted
  • Location: @scotlandwx
  • Weather Preferences: Crystal Clear High Pressure & Blue Skies
  • Location: @scotlandwx

..., if you look to the USA you can see the jet is totally flat right the way out into the Pacific, theres nothing there to interrupt the flow and until we see changes upstream with much more amplification then its a case of moving from the recent Euro ridge/ trough to the west stalemate to Euro ridge to the south/troughing to the north stalemate.

This amplification change is what I had hinted at earlier at around the 150 mark with the jet responding to a weak high on the NW US Seaboard creating some energy above a slow Greenland high. Very, very weak signal completely over ridden with the main falt picture you describe.

Is this straight across the US from W>E flat jet common in La Nina Winter or are we flirting with a non determinate base state.?

From Scandi High to flat Jet - there is not a lot of promise at all in the models for cold, looking hopefully at the strato charts leads to warming at phases that will not carry down welling and the MJO appears to have weakened. All points back to GPs winter thoughts, that slide run is on the money right now.

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

This amplification change is what I had hinted at earlier at around the 150 mark with the jet responding to a weak high on the NW US Seaboard creating some energy above a slow Greenland high. Very, very weak signal completely over ridden with the main falt picture you describe.

Is this straight across the US from W>E flat jet common in La Nina Winter or are we flirting with a non determinate base state.?

From Scandi High to flat Jet - there is not a lot of promise at all in the models for cold, looking hopefully at the strato charts leads to warming at phases that will not carry down welling and the MJO appears to have weakened. All points back to GPs winter thoughts, that slide run is on the money right now.

Regarding La Nina it's effected by so many other teleconnections,in terms of that upstream pattern a negative PNA isn't great for cold lovers over there or here.

The stratosphere is getting colder:

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_MEAN_OND_NH_2011.gif

As you can see yet more grim news!

Generally the only way you get temps below average in the UK with a positive AO and NAO is by the much maligned Euro high, if the jet kicks so far ne it can allow it far enough north to give that surface cold, but you need it orientated in a way that cuts off the warmer southerly component.

Given the strat signals if I had to choose a plausible route to some frostier conditions it would be through the Euro high.

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

Hello Summer blizzard,

Would you say la nina was more typical to the blocked anticyclonic conditions we have seen for the past month or so then?i was under the impression la nina was more associated with slightly more atlantic dominated weather patterns?for the uk.i am a little naive so any advice would be much appreciated,cheers.

For a strengthening La Nina like we have now, cooler temperatures and higher pressure over the UK is usually indicated especially in the November-December period.

The current pattern has seen the block much further east than normal due to above average GLAMM readings.

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet

This amplification change is what I had hinted at earlier at around the 150 mark with the jet responding to a weak high on the NW US Seaboard creating some energy above a slow Greenland high. Very, very weak signal completely over ridden with the main falt picture you describe.

Is this straight across the US from W>E flat jet common in La Nina Winter or are we flirting with a non determinate base state.?

From Scandi High to flat Jet - there is not a lot of promise at all in the models for cold, looking hopefully at the strato charts leads to warming at phases that will not carry down welling and the MJO appears to have weakened. All points back to GPs winter thoughts, that slide run is on the money right now.

The chart shows a flat Jet Stream in the Pacific but a fairly amplified in the USA with a western trough and eastern ridge which is indeed the default pattern for the strengthening La Nina/-PDO combination.

In regards to the models this evening we do see a divide between the ECWMF and GFS in the 5-10 day range.

At day 5 both models do have a negatively tilted Azores High (a positive in my opinion as the Jet orientation is NW/SE even if it cannot undercut the block) however at day 10 while the ECWMF retains this pattern, the GFS has a positively tilted Azores High resulting in a zonal pattern.

In regards to the ensembles there are some that offer scope of cooler weather from the 19th although none are cold enough for lowland snow until the 23rd and the mean is not below average until the 29th.

For those interested in early December check out the technical thread in about ten minutes.

Edited by summer blizzard
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