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Model Output Discussions 12z 01/09/2016


phil nw.

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Posted
  • Location: st albans
  • Location: st albans
1 minute ago, knocker said:

To be fair blue some of us do have an interest in the here and now as well as the forth coming deep freeze.

Seriously knocker - how long have you been here !  October weather just doesn't cut it in any direction 

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Posted
  • Location: Camborne
  • Location: Camborne
Just now, bluearmy said:

Seriously knocker - how long have you been here !  October weather just doesn't cut it in any direction 

Perhaps we should just suspend the thread for a month then.

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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

As expected the ECM is markedly different to the GFS run, keeping things blocked and mainly dry and settled. More runs needed!

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Posted
  • Location: Camborne
  • Location: Camborne

Naturally the ecm run bears no resemblance to the GFS.

It does have the deep upper low west of Iberia midnight Monday but it has strong ridging in mid Atlantic which moves east cutting off the low in situ which has the affect, with HP stretching from the west around Scotland to the NE of leaving the UK more or less in an easterly flow for the rest of the run. The evolution from the weekend still isn't sorted.

ecm_mslp_uv850_natl_8.png

 

Edited by knocker
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Posted
  • Location: Wakefield, West Yorkshire
  • Location: Wakefield, West Yorkshire
8 hours ago, bobbydog said:

They are forecast to go slightly positive though, before tanking into negative. As is the mean zonal wind.

nao.sprd2.gifu_65N_10hpa.png.5d1b7e381c8ec0f6d3ba00e9c7adbb6e.png

Like a deep breath before the plunge into winter...

Interesting, thank you very much.

:-)

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Posted
  • Location: Wakefield, West Yorkshire
  • Location: Wakefield, West Yorkshire
7 minutes ago, mb018538 said:

As expected the ECM is markedly different to the GFS run, keeping things blocked and mainly dry and settled. More runs needed!

Wow, ECM and GFS couldn't be more different if they tried. 

ECM keeping the Easerly type component, and GFS bringing the Atlantic back. 

FI as early at T+120 based on the overnight output  

 

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Posted
  • Location: Newton Poppleford, Devon, UK
  • Weather Preferences: Snow, Thunderstorms, High Winds.
  • Location: Newton Poppleford, Devon, UK

The GFS model and the ECMWF model show a high over Ireland and SW parts of the UK bringing light NW winds and cool temperatures to all parts of the UK tomorrow and a high over Ireland and NW parts of the UK bringing light N winds and cool temperatures to all parts of the UK on Thursday.

gfs-0-24.png gfs-1-24.png gfs-0-48.png gfs-1-48.png ECM1-24.GIF?18-12 ECM0-24.GIF?18-12 ECM1-48.GIF?18-12 ECM0-48.GIF?18-12

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Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK

.Morning all. Yes, big difference between Euros and American models as we head to the month end. I think this picture from ECM is a safe bet and probably backed by UKMO outputs this far out ( 240 hours ) The block continues with the jet deflected away from much of Europe with the far SW of Britain only at risk for a short time from Atlantic frontal systems. Will be interesting to see if GFS and to lesser extent the Canadian model back the Euros and the UKMO thoughts to 10day forecast period. I think they will come on boorad with later runs today. In the shorter term here in the Alps, a fall in temperature expected in line with much of Europe during the rest of the week . Our fine mesh snow model goes for 21cm of fresh snowfall byThursday morning at our specific grid reference. Now that's being precise ! I will take a measurement on Thursday Hope its spot on.

ECMOPEU00_240_1.png

Edited by carinthian
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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

Won't be much snow left if that ECM comes off Carinthian! 850s of 10-15c certainly aren't what the doctor ordered this late in the year! :blink2:

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Posted
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Ski Amade / Pongau Region. Somtimes Skipton UK
12 minutes ago, mb018538 said:

Won't be much snow left if that ECM comes off Carinthian! 850s of 10-15c certainly aren't what the doctor ordered this late in the year! :blink2:

Yes, the upper flow at 2000m height is too warm for lasting snow. Strange thing is the valley will be much colder with a surface flow. However, I expect the temperature height differentials boundary to be quite acute with Austrian resorts closer to single digit 850s.

 C

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Posted
  • Location: Camborne
  • Location: Camborne

The EPS mainly supports the det. run with low pressure to the south west and high to the NE thus a flow from the easterly quadrant with temps around average although rather depending on wind strength as to how that feels. As we move into the later period the main area of HP retrogresses but low pressure weakens and slips away as well allowing pressure to rise adjacent to the UK and the upper flow veering from easterly to the south west.

ecm_eps_z500a_5d_natl_11.pngecm_eps_t850a_5d_natl_11.png

Edited by knocker
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Posted
  • Location: st albans
  • Location: st albans

It just occurred to me knocks that you are viewing the SLP/anomaly rather than heights/anomly

At a range post day 10 I could never use slp without any clustering charts or spreads. Too much reversion to climatology imo.

The height anomaly days 10/15 look to offer support for further mid Atlantic height rises to our wnw in conjunction with potential trough west of Iberia- ergo more of the same

 

 

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Posted
  • Location: Camborne
  • Location: Camborne
1 hour ago, bluearmy said:

It just occurred to me knocks that you are viewing the SLP/anomaly rather than heights/anomly

At a range post day 10 I could never use slp without any clustering charts or spreads. Too much reversion to climatology imo.

The height anomaly days 10/15 look to offer support for further mid Atlantic height rises to our wnw in conjunction with potential trough west of Iberia- ergo more of the same

 

 

Actually no I'm not blue. I use the 500mb anomaly but I do cross check it with the 850mb streamlines chart ( It does give some indication of the possible surface set up). I never use the SLP anomaly. I also appreciate that there is a tendency to default to climatology which is why it's wise to keep in mind that we are just looking for trends here and should always be used in conjunction with other anomalies and even keeping an eye on the det. outputs.

Having said that this is what I actually said:

Quote

but low pressure weakens and slips away as well allowing pressure to rise adjacent to the UK and the upper flow veering from easterly to the south west.

Looking at the 10-15 chart I think with the HP retrogressing to the NW and the trough becoming ineffectual surface pressure will build over or adjacent to the UK veering the wind to the SW quadrant. You obviously disagree with my interpretation of this so we will have to agree to differ.

In a nutshell what I'm suggesting is that around T276 the low to the SW begins to weaken and with that HP is being pushed from central Europe which will off the SE flow.

eps_z500a_5d_exatl_61.png

EDIT

I also note that seven others think I am wrong as well. Such is life but I must admit I'd be interested in their reasoning.

Edited by knocker
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Posted
  • Location: Batley, West Yorkshire
  • Weather Preferences: Heat and Snow
  • Location: Batley, West Yorkshire

The trend has been continuing to build throughout October for significant blocking over Scandi. The latest ECMWF monthly and GLOSEA5 confirm this trend will continue into November. The PV looks a totally different shape than it did this time next year and I remain convinced this winter will be far better than last year based on the models and background signals

Edited by Barry95
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Posted
  • Location: Manchester
  • Weather Preferences: Sunny and warm in the Summer, cold and snowy in the winter, simples!
  • Location: Manchester

A bit of a confused picture this morning but overall the output is less inclined to build heights into Greenland with the old winter enemy, low heights SW tip of Greenland, refusing to be banished.

Generalising further for end of Oct/early Nov this "may" lead to a more traditional pattern emerging for a while (based on GFS) with low pressure systems crossing to the N of the UK - how far N these are deflected is uncertain but if GFS is correct there is potential for a wet and windy spell for NW UK. However it does not currently look like this pattern would settle into a typical zonal spell and there is a clear signal within GFS ensembles to have the jet push South and an Atlantic ridge rebuild early into Nov.

ECM wants to b more stubborn with the blocking but it has clearly moved toward the idea of the jet going over the top of the block from mid to late term with spoiler lows SW of Greenland so no possibility of retrogression or heights building into Greenland proper if that is correct either.

 

Based on all the  output I would say that a decline in blocking through the last week of October and into early Nov looks likely before blocking reestablishing itself in the Atlantic (possibly introducing a cold snap/spell later first week of Nov except Fergie's update somewhat contradicts that with the UKMO and Glosea5 having a blocked signal through this period. 

This apparent contradiction within the output could be reconciled by a reduction in blocking  but with high pressure generally remaining in control over the UK before it is displaced West by a trough digging into Scandinavia to produce the positive height anomaly to the NW of the UK Fergie mentions.

All in all plenty to watch for over the coming days and to see if the models gain any real appetite for a possible cold snap/spell early Nov.

Personally I will be happy just to see some form of blocking persist or reestablish itself into early nov.

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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
1 hour ago, knocker said:

Actually no I'm not blue. I use the 500mb anomaly but I do cross check it with the 850mb streamlines chart ( It does give some indication of the possible surface set up). I never use the SLP anomaly. I also appreciate that there is a tendency to default to climatology which is why it's wise to keep in mind that we are just looking for trends here and should always be used in conjunction with other anomalies and even keeping an eye on the det. outputs.

Having said that this is what I actually said:

Looking at the 10-15 chart I think with the HP retrogressing to the NW and the trough becoming ineffectual surface pressure will build over or adjacent to the UK veering the wind to the SW quadrant. You obviously disagree with my interpretation of this so we will have to agree to differ.

In a nutshell what I'm suggesting is that around T276 the low to the SW begins to weaken and with that HP is being pushed from central Europe which will off the SE flow.

eps_z500a_5d_exatl_61.png

EDIT

I also note that seven others think I am wrong as well. Such is life but I must admit I'd be interested in their reasoning.

I thought you would have enough on your plate locking horns with bluearmy without bringing another 7 into the mix lol. Anyway, you did ask so here goes. Any wind veering to the SW quadrant would be very transitory to say the least and still questionable. What would be far more significant is what comes after - a good chance of an early north easterly blast.

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Posted
  • Location: Camborne
  • Location: Camborne
15 minutes ago, blizzard81 said:

I thought you would have enough on your plate locking horns with bluearmy without bringing another 7 into the mix lol. Anyway, you did ask so here goes. Any wind veering to the SW quadrant would be very transitory to say the least and still questionable. What would be far more significant is what comes after - a good chance of an early north easterly blast.

As a matter of interest I'm not locking horns with bluearmy but I reserve the right to defend and explain my position if someone disagrees with it.. If what they say makes sense to me I do not have a problem with that and moving on but in this particular instance I do not agree and have explained why. In the process I noted that others agree with him so I do not feel it unreasonable to wonder what their meteorological reasoning is behind their disagreement with my original comment And the question isn't about whether it is transitory or not but what the EPS is actually saying about the evolution between 10 and 15 days..

Edited by knocker
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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL

No point thinking too much about FI, day 5-7 is where it's happening - will the high hold to our NE, will it retragress NW , or will the Atlantic make some form of inroad - a fair few ENS go with the middle one so I'm hoping they're right. Anyway, when was our last country wide cold bonfire night? I seem to remember wrapping up in the 80s, that may have been due to me being a young lad and my Mother flapping however.

Edited by Ali1977
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Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire

It will be interesting to see if the gfs goes back towards building heights to our north west in week 2. The operationals were very keen on this not so long ago. I wonder if it is going to be one of those ocassions when an idea is picked up on, then ditched and then picked up again. All the models are prone to this and I suppose that makes sense when all the variables are constantly changing.

Edited by blizzard81
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