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Model Output Discussions 12z 01/09/2016


phil nw.

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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 thought there would be more comments about how unseasonably warm this week will become as we are almost at the end of october..it's going to become remarkably mild, especially across the south during the second half of this week..very pleasant indeed!:shok::D

Ecm 00z..

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Edited by Frosty.
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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

Another run from ECM which backs away from the cooler / colder air coming our way

Recm1442.gifRecm1682.gifRecm1922.gifRecm2162.gifRecm2402.gif

 

Nothing nailed on yet by any means before any colder air possibly comes our way this week will see temps trending up likely to be in the upper teens later this week in the south very pleasant indeed for the time of year

 

Edited by Summer Sun
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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk
32 minutes ago, Summer Sun said:

Another run from ECM which backs away from the cooler / colder air coming our way

Recm1442.gifRecm1682.gifRecm1922.gifRecm2162.gifRecm2402.gif

 

Nothing nailed on yet by any means before any colder air possibly comes our way this week will see temps trending up likely to be in the upper teens later this week in the south very pleasant indeed for the time of year

 

ive been on the fence the last couple of days,

 it certainly looking like a pretty big climb down although the gem still wants to at least put heights into the atlantic the only thing that maybe swinging recent runs away is that the vortex is awakening and perhaps anymore northern blocking may well not get established because of this very reason.

so easy to go down the garden path and read into fi charts lets hope we keep the trend we were seeing going.

but im staying on the fence. 

Edited by MR EXTREMES
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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

Mixed runs this morning from the main models. Timing is the main issue regarding how we access the colder flow with Arctic air mass mix. The GFS chart below interests me most of all from a cold perspective at 240 time span. Certainly a quicker route to a much colder flow than ECM but possibly more in line with UKMO thinking to turning much colder in the 7-10 day outlook period. Note the flow  of colder mass from Scandinavia towards Southern Britain with possible trough formation . Would eventually engage with warmer moist air from the developing circulation NE of the Azores as seen on this chart. All this in the longer term could produce some very wet conditions for Southern Britain with marginal snow boundary further north. Great chart viewing continues.

 C

hgt500-1000.png

Edited by carinthian
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Posted
  • Location: Nr Chelmsford, Essex
  • Weather Preferences: Hurricanes, Thunderstorms and blizzards please!
  • Location: Nr Chelmsford, Essex
12 minutes ago, Minus 10 said:

To puts things in perspective here is a chart from last winter

archivesnh-2015-12-5-0-0.png

Now here is the ECM 144 forecast

ECH1-144.GIF.png

No worries from me, as long as the northern hemisphere profile is looking like the latter then I am extremely happy going into winter (from a coldie point of view).

100% agree.  It's probably 3/4 weeks too early to expect any potent cold shot anyway, certainly away from the Highlands of Scotland.  The outputs will likely wax and wane until the strength and position of any blocking becomes established.  However, if the NH profile continues to look anything like this over the next couple of months, it will be just a matter of when, not if, we get some proper cold in.

We just don't want that PV to get it's act together anytime soon.

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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

The GEFS 00z mean shows an exceptionally pleasant outlook, initially across the south but then extending up across the rest of the uk as high pressure builds north with an air mass sourced from southern europe so it's goodbye cool Easterly and hello balmy warm Swly / Sly flow.:)

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Edited by Frosty.
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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk
15 minutes ago, MP-R said:

Perhaps a more direct comparison given the date:

archivesnh-2015-10-30-12-0.png

just to show what i was meaning if you run through the gfs run you see the larger part of the vortex swinging round to back up the cheesed of vortex.

now the azore heights need to be strong and quick enough to win the race for greenland blocking. and we need the low to our north to drop south or southeast to lower the heights to our south so this is why im on the fence and after days of eye candy i only see a slight chance of greenland heights,

although the nao and ao index do still go neg although suspect if the models continue to churn out charts like this mornings then you could safely say a steady rise in the nao.

this must have something to do with the vortex getting the hump and possibly pushing more back to its usual location.

modified gfs.png

 

Edited by MR EXTREMES
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Posted
  • Location: Camborne
  • Location: Camborne

A quick look at the hemispheric picture, if I may be so bold, with this morning's 6-10 anomalies

Regarding the overall pattern they are both on the same ball park with the Aleutian low, small vortex N. Canada, Russian ridge into the Arctic with continuation of the WAA in that area. and trough in eastern Europe. The differences lie in the Atlantic and this is causing a certain amount of uncertainty with the det runs and until this is sorted one feels a certain amount of chopping and changing will continue. Not that the differences are huge but enough to upset the kilter.

ecm_eps_z500a_5d_nh_11.pnggefs_z500a_5d_nh_41.pngecm_eps_t850a_5d_nh_11.png

 

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Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset
12 minutes ago, MR EXTREMES said:

just to show what i was meaning if you run through the gfs run you see the larger part of the vortex swinging round to back up the cheesed of vortex.

now the azore heights need to be strong and quick enough to win the race for greenland blocking. and we need the low to our north to drop south or southeast to lower the heights to our south so this is why im on the fence and after days of eye candy i only see a slight chance of greenland heights,

although the nao and ao index do still go neg although suspect if the models continue to churn out charts like this mornings then you could safely say a steady rise in the nao.

this must have something to do with the vortex getting the hump and possibly pushing more back to its usual location.

modified gfs.png

 

Oh yes absolutely. My post was in response to Minus 10's. Fortunately we don't have anything like the Atlantic bomb that lasted through November and December last year. In fact the amount of yellow/orange on last year's charts compared with the greens of this year's across Europe is noticeable.

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

Those Greenland blocks, such elusive beasts.

Just 12h between these GFS runs and only 6 days out.

gfsnh-0-162.pnggfsnh-0-144.png?6

Thank goodness it is October. :D

As others have said, it is a timely reminder that nothing is in the bag, when it comes to Greenland blocking anyway, until inside 120h at the latest. To be perfectly honest it would have been a bit of a waste of some fantastic cold potential so early in the season, let's just hope we get HLB in the right places when it counts.

It is still a case of big picture for the Winter which still holds more promise than recent Winters as far as cold and snow prospects go - yes patience is a virtue when it comes to Winter model watching. (Not saying I have any :closedeyes:)

On that note the charts still hold interest in the 10 to 15 day range for some time despite forecast easing of a strongly negative NAO - I still do not see charts with the jet roaring across the Atlantic and taking aim at us as is traditionally the case around early November.

 

All we need now, for the full winter warm up, is for the models to flip back to a Greenland high then back away again over the next 24h, that should have us all fit for Winter season model watching.

 

PS.

If there was one model that was never very keen on Greenland blocking (aside from UKMO which we don't really know about) it was JMA. That may or may not be relevant next time we see Greenland blocking being modeled. 

 

 

 

Edited by Mucka
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Posted
  • Location: Camborne
  • Location: Camborne
1 hour ago, Singularity said:

In terms of the possible initial chill-out to start Nov we do seem to have just witnessed a classic case of the 'shortwave spoiler'; a small low on the peripahery of an (usually) Atlantic trough that changes the angle of the jet stream enough for it to ride up over a blocking high rather than up the western flank to sustain it via movement of warm air to the high latitudes.

 

I'm sorry I'm not sure I follow what you mean and would be grateful for a quick illustration if possible. I ask because to my untutored eye it looks very much like the energy shooting out from the north Canadian vortex that is creating the very tight thermal gradient and the 160Kt west-east jet and not allowing the HP to ridge into Greenland.

gfs_z500a_natl_14.pnggfs_uv250_natl_14.png

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

Rukm1441.gif

It's this elongated low pressure throwing a spanner in the works really. I'm not sure if you've been watching the last 2-3 days (?), but this feature hasn't really been shown at all until this morning, with repeated output showing the high being pulled out west towards Greenland without interference. The joys of model watching! Expect the unexpected, don't be surprised when things like this happen :D

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

However you look at the models this morning, one thing that stands out towards the start of November onwards is the distinct lack of any PV - particularly around the Greenland and Canada area which is great to see from a coldies view at this point of the year .  The ENS currently coming out show this well but I can't load pictures, the mean beyond 240 looks fantastic for colder shots further into November and looks very interesting for sure (only 4 of the 20 show anything resembling the beginnings of stronger PV).

I wouldn't be too let down by the failing (not failed by any means just yet) northerly at the start of Nov, it would be kind of wasted anyway as no cold air close by to tap into, this may well change by mid November.

The latest GEM run shows a different way of handling the block, a big Greeny/Scandy high and the cold weather gathering up in Northern Europe - again, sorry I can't post pictures.

Edited by Ali1977
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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

well, re my post sometime yesterday about the anomaly charts, below is that from EC-GFS this morning. Certainly not a clear endorsement of the NOAA idea but EC goes some way towards it, not sure what the fairly intense cut off upper low is nw of the UK though; GFS still more ridge inclined but it again shows a flow  north of west into the UK, link below

I would still go for the 6-14 day OVERALL contour flow to be along the lines suggested by NOAA.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Edited by johnholmes
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Posted
  • Location: st albans
  • Location: st albans
9 minutes ago, johnholmes said:

well, re my post sometime yesterday about the anomaly charts, below is that from EC-GFS this morning. Certainly not a clear endorsement of the NOAA idea but EC goes some way towards it, ot sure what the fairly intense cut off upper low is nw of the UK though; GFS still more ridge inclined but it again shows a flow  north of west into the UK, link below

I would still go for the 6-14 day OVERALL contour flow to be along the lines suggested by NOAA.

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Hi John - the upper low is on the 00z ecm op run so it's bound to be on a chart showing the average of the run days 6/10 ??

remember that this Chart is a representation of the ecm /gfs op runs only. Nothing to do with the ensembles 

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)
3 hours ago, knocker said:

I'm sorry I'm not sure I follow what you mean and would be grateful for a quick illustration if possible. I ask because to my untutored eye it looks very much like the energy shooting out from the north Canadian vortex that is creating the very tight thermal gradient and the 160Kt west-east jet and not allowing the HP to ridge into Greenland.

gfs_z500a_natl_14.pnggfs_uv250_natl_14.png

Hi Knocker, thanks for the question.

h850t850eu.pngh850t850eu.png

What we've seen is a change to the behaviour of that little low to the west of the main one situated just N of Iceland; last night's 12z (left) had it absorbed into the parent low without causing trouble, while today's 00z (right) keeps it independent, which means it can interact with the low to the S of Greenland, their combined effect producing the undesirable jet stream alignment by the next day:

hgt300.png hgt300.png

Gone is the buckling jet arcing back to the NW in favour of a flat one heading NE - albeit not with all that much strength.

The strong jet that you've picked out is a part of the equation of course - a slight increase in its intensity has allowed the low S of Greenland to progress further east at the time that the shortwave low offers to dance. Without that, the two may still have been having nothing to do with one another in the model output.

With that shortwave's behaviour, it's actually not the most classic of examples to be honest, that being a shortwave on the eastern flank of a trough, but it may be the second or third-most classic, so to speak? :ninja::laugh:

Anyway - I'm not yet seeing reason to entirely rule out (or expect, for that matter) the low S of Greenland being slower, or the shortwave low being absorbed into the parent low after all, either of which could prevent their interaction and reintroduce the colder outcome for the earlier part of next week. The situation is finely balanced.

Edited by Singularity
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