Model Output Discussion 12hrs. 01/10/13

[smithyweather]

In what way? Do you mean in a 2010 style? I.e warm and suddenly get very cold?

[damianslaw]

In what way? Do you mean in a 2010 style? I.e warm and suddenly get very cold?

 

 

No not quite on that scale, more to something like which occured in late October 2008 and 2012 i.e. a northerly plunge thanks to a split jet with energy being reinvigorated into the southern arm - with heights transferring to our NE sending the trough on a NW-SE path twith subsequent height rises to the NW - if energy in the polar vortex remains in current situ - such a synoptical evolution is very probable.

 

The key determinant factor at present is the position of the polar vortex.

[johnholmes]

I know some do not have the same trust in the anomaly charts WHEN they are consistent from day to day and with one another but the 2 below give an indication of what the upper air is most liely to be similar to in the 6-15 day time scale, that is late October. Nothing there in the charts suggests major changes in the pattern or wavelength. They are being consistent over the last 3 days so I would be very surprised if the upper air pattern is markedly different come 19 October or indeed by 5-7 days after that.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php

 

Does anything further out suggest they may change after this?

The MJO is currently in 6,

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/whindex.shtml

 

the forecast is for this

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foroper.shtml

 

again a low orbit so its effect is unlikely to have any effect on what we already have.

 

and a fairly low orbit, which suggests 

http://www.americanwx.com/raleighwx/MJO/MJO/OctoberPhase6500mb.gif

 

The AO and NAO (yes i know only a mirror in a way of the synoptic patterns on the models) but neither do they support any marked change from what we have.

 

So I cannot yet see when the current upper pattern is going to change, the major troughs are around the areas west of Alaska and south of Greenland, then way off the northern end of the chart, showing a very large amplitude. Once this type of 3 main trough set up occurs it is quite a long process to change it. I do not have the knowledge to even suggest when or how this might happen. It MIGHT be a tropical storm/Hurricane develops at last. This would certainly have some effect on this long wave pattern. Is there one around?

answer=http://www.nhc.noaa.gov/archive/2013/al11/al112013.discus.020.shtml?

 

That seems unlikely, from present data, to be the one but who knows one may develop in the next 2-3 weeks. Their development coming off western Africa is an unknown quantity, only once they have begun to show certain characrteristics do NOAA get a grip on what they may do. Certainly none of the other models do at that stage and the anomaly charts are notorious at showing anything at 500mb until late in the day.

Edited October 3, 2013 by johnholmes

[Bristawl Si]

Will the UK end up with one of the most calm weatherwise October's in recent years?

[Frosty.]

Well although my name on here is Frosty, I'm enjoying this extended warmth and looking forward to an anticyclonic and very warm spell by october standards. The charts today are again choc full of potential for a memorabe spell of indian summer weather....BRING IT ON I say : - )

[Captain Shortwave]

 

 

That will do nicely, high now positioned further east, better upper, continental flow. Warm and sunny once mist and fog clears each morning

[Geordiesnow]

Why are people saying the current pattern is blocked? Its not, its a pattern for cold lovers should be glad its happening now and not in the middle of winter! Cold air is finally filtering through Svalbard and for a change, Northerly winds could be dominating in this area for the foreseeable instead of Southerlies. This tends to suggest low pressure at higher latitudes and thats what we are seeing.

 

All the blocking highs are at mid-latitudes which is more normal so in essence it is a normal pattern we are seeing here. Got to say, this current settled spell coming up does look quite cloudy because of such a moist airflow with the best of any breaks occuring in sheltered eastern areas. 

 

Theres a small possibility of the high heading NW'wards to perhaps allow something cooler to come down from the North as we head into the medium term but this is only a small risk at this risk, most models suggest the high staying over the UK and heading eastwards allowing the warm Southerlies to continue. 

[Frosty.]

Ukmo 00z shows a classic retrogressive pattern with the first strong Northerly blast of the season incoming as high pressure is sucked west/nw and a trough dive bombs south through scandinavia, this would bring showers south and they would turn to snow on scottish mountains and wintry on higher hills in the north but the Ecm 00z is having non of that and looks very anticyclonic, high pressure slap bang on top of the uk, so the euro models are rather conflicting at T+144 hours. or my money would be on

Edited October 4, 2013 by Frosty.

[Captain Shortwave]

Models this morning at day 6

GFS

 

UKMO

 

GEM

ECM

GFS ens

 

So a nice scrambled mess of disagreement then 

[shedhead]

Once again plenty of great looking charts there for very warm, sunny weather if it were Summer CS, especially the GFS mean, but much as during the last spell mist, low cloud and fog is bound to play a part for many. That said I will be more than happy with another lengthy benign spell, hopefully allowing what is now saturated ground around here to dry out a bit, because the westerly gales and rain are coming.....it's just a matter of when.

 

My fear is if they don't come in autumn though they'll almost certainly come in Winter.

Edited October 4, 2013 by shedhead

[draztik]

The Thursday night update of the ECM monthly shows increasingly unsettled weather from around the middle of the month onwards, esp for N.I. and Scotland. The SE may be protected by slight ridging, as has been the case since May. Temperatures look to be around average, with above average conditions slated for Glasgow, tho with the caveat that a lot of rain is expected here. So as we move into November, the ec32 offers little hope of very cold weather at this stage.

[Summer Sun]

The ECM ensemble agrees with the Op by keeping pressure right over the UK at t144 not interested in UKMO's northerly

 

 

Op

 

 

Basically its as you were from ECM with high pressure dominating for the foreseeable future

 

Day 10 shows no end in sight and this continues to have ensemble support

 

 

ensemble

 

 

GFS ens at day 10 also has the high dominating

 

 

Not interested in UKMO's northerly either

 

Edited October 4, 2013 by Summer Sun

[Frosty.]

Just as I thought, the ukmo 00z is avin a laff

[Summer Sun]

Latest from Gibby

 

Good morning folks. Here is this morning's trip through the midnight outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Friday October 4th 2013. Sorry about the wide paragraphs my normal pretty troublefree transfer method failed me this morning.

 

All models show the remnants of this weeks warm and moist airflow exiting Northern Britain to be replaced by a fresher West wind and fast rising pressure today from the South. By Tomorrow and Sunday Southern areas will of become under the influence of High pressure close by with fine and dry weather with the risk of overnight mist and fog patches. Further North a Westerly breeze will persist carrying cloud in association with Atlantic troughs with occasional rain through these areas for the weekend and start of next week. From then all models diversify in the way they show High pressure affecting the UK.

 

GFS quickly builds High pressure through all of Britain early next week with fine and dry days but potentially foggy night which would likely be slow to clear each day. the nights would be cooler than of late and this will extend to the days too if fog fails to lift significantly enough. Later in the week and Easterly breeze may lift fog to low cloud in the South which could prevent it from forming overnight here otherwise little change is expected next weekend. through the second half of the run High pressure drifts far enough East at times to allow some ingress of Low pressure from the Atlantic with occasional rain at times almost anywhere. However, as shown it would not be a significant breakdown with mist and fog in the continuing light winds still likely with near to average temperatures.UKMO keeps the north rather changeable to start the new week before High pressure builds across all areas with a centre to the NW which would serve to carry colder and fresher air steadily South over the UK next week with mist and fog highly likely and maybe some ground frost in the North later.

 

GEM also shows a changeable start to the new week in the North while the South stays dry before a build of pressure from the North this time settles over Scandinavia towards the end of next week and the weekend with a mild ESE flow developing over Southern and Western areas. most places will stay dry throughout with fog at night becoming less likely in the fresher breeze at the end of the run.NAVGEM shows that after a few unsettled days for Central and Northern areas early next week as shallow Low pressure crosses the weather would settle down again for all as High pressure moves down from the NW covering the UK at the end of next week with fine and dry conditions but extensive mist and fog night and morning when it would feel cool.

 

ECM shows high pressure well established right over the top of the UK for much of next week before it slides away ESE next weekend as troughs edge in slowly from the SW in a slowly freshening SE breeze. despite this most places will hold dry through the latter stages of the run with the incidence of fog a major issue almost anywhere night and morning with the risk only slowly lessening into low cloud as the SE feed increases at the end of the run.The GFS Ensembles show remarkable consistency this morning for temperatures to hold 2-3C above normal aloft over the period of the coming two weeks with very little rainfall anywhere considering we will be deep into October.

The Jet Stream is currently realigning it's position to settle well to the NW and West of the UK over next week and probably beyond as it is steered around the High pressure which will become parked near or over the UK.

 

In Summary the weather next week and probably beyond remains set fair as High pressure becomes the dominant player in the weather over the UK. The main issue will be one of fog and temperature. If fog forms it will become hard to clear in the morning with the greatly weakened strength of the sun now and if that is the case the cooler nights than of late will extend through the days too making for typical quiet Autumnal weather. However, where it does clear with warm air aloft temperatures will respond well and the afternoon's could become quite warm. It is hard to see from this morning's output where the next significant unsettled weather will come from with a weak bias towards an ingress of the Atlantic late on in some extended outputs I've seen but there is hardly enough evidence to suggest this as a trend.

 

http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

[Summer Sun]

MOGREPS is going for this settled spell as well so I think we can ignore UKMO's northerly

 

@MattHugo81 

 

The persistence of pressure above 1020mb from the 12Z GFS ENS is quite remarkable - http://modeles.meteociel.fr/modeles/gens/graphe_ens4.php?x=250&y=40&ext=1&run=12&runpara=0 â€¦ - An high pressure outlook!

 

@nudeweatherman

 

@MattHugo81 MOGREPS-15 had the same signal today, maybe a tad less cyclonic week 2 as well. Looking good for a settled spell.

 

@MattHugo81

 

@nudeweatherman EC clusters have shifted that way as well generally with a far more anticyclonic pattern *almost* nationwide

 

[tempestwatch]

The ECM ensemble agrees with the Op by keeping pressure right over the UK at t144 not interested in UKMO's northerly

 

 

Op

 

 

Basically its as you were from ECM with high pressure dominating for the foreseeable future

 

Day 10 shows no end in sight and this continues to have ensemble support

 

 

ensemble

 

 

GFS ens at day 10 also has the high dominating

 

 

Not interested in UKMO's northerly either

 

Hi, it is sometimes confusing as a relative newby that you often see two posts like yours and Drazztic's together (186). One says relatively benign weather for the near future and no sign of change at day 10 and the other says increasing signs of unsetteld weather from mid month.I know that everyones comments are valid and i enjoy reading them, can you tell me what the differences are on the ECM that you both may be seeing differently? I am very much on a steep learning curve and would like to be able to recognise the differences that make people have different predictions.

[Captain Shortwave]

Hi, it is sometimes confusing as a relative newby that you often see two posts like yours and Drazztic's together (186). One says relatively benign weather for the near future and no sign of change at day 10 and the other says increasing signs of unsetteld weather from mid month.I know that everyones comments are valid and i enjoy reading them, can you tell me what the differences are on the ECM that you both may be seeing differently? I am very much on a steep learning curve and would like to be able to recognise the differences that make people have different predictions.

Draztik's post is referring to beyond mid-month, obviously the ECM 32 dayer is moving to a pretty standard October pattern of a north/south split in conditions.

I have to admit I'm a little disappointed by that update. Given the CFS/JMA/Beijing climate models are trying to push for a colder and wetter end to October (by cold I mean below to well below average) with a trough over central Europe, it seems the ECM is going for the exact opposite here.

[tempestwatch]

Draztik's post is referring to beyond mid-month, obviously the ECM 32 dayer is moving to a pretty standard October pattern of a north/south split in conditions.

I have to admit I'm a little disappointed by that update. Given the CFS/JMA/Beijing climate models are trying to push for a colder and wetter end to October (by cold I mean below to well below average) with a trough over central Europe, it seems the ECM is going for the exact opposite here.

Thanks CS!

[Frank Trough]

MOGREPS is going for this settled spell as well so I think we can ignore UKMO's northerly

 

@MattHugo81 

 

The persistence of pressure above 1020mb from the 12Z GFS ENS is quite remarkable - http://modeles.meteociel.fr/modeles/gens/graphe_ens4.php?x=250&y=40&ext=1&run=12&runpara=0 â€¦ - An high pressure outlook!

 

@nudeweatherman

 

@MattHugo81 MOGREPS-15 had the same signal today, maybe a tad less cyclonic week 2 as well. Looking good for a settled spell.

 

@MattHugo81

 

@nudeweatherman EC clusters have shifted that way as well generally with a far more anticyclonic pattern *almost* nationwide

 

I don't know if we should ignore it entirely - the GFS does show how we could have a (not cold) but cooler glancing blow from a northerly followed by high pressure building back over us and eventually drifting further east. But a full on northerly looks like a long shot at present. 

 

so no real change in the broad outlook, though. I wonder if the METO update today will ditch the "unsettled weather moving southeast" theme today? 

 

I'd take the ECM outlook at  the drop of a hat to be honest. Extends the fishing season nicely! 

[Tamara]

The EPS members, as ever, give a bit more insight into the potential model trends than the ensemble mean and show that, whilst support is quite low, there are a few amplified solutions not too dissimilar to the UKMO this morning - so it is not a complete outlier any means

 

 

The overall agreement is for high pressure dominance, and hence the straightforward look to the ensemble means, but the exact positioning and orientation of the high pressure has taken on a little uncertainty with the trough to the north east looking sharper and likely to pull down further south from the Siberain side of the arctic than was initially modelled. This means that colder uppers seem likely to advect through north eastern, and eastern/central europe at least. It is the westward extent of this airstream that will determine conditions under the high pressure close to the UK

 

This positioning and orientation of the high will be critical as to conditions at the surface in terms of cloud cover, wind source, amounts of sun etc etc. So its one of those situations where the closer detail actually shows that the upcoming high pressure may not mean straightforward warm autumn sunshine by day after misty mornings.

 

The probabilities remain low that the more amplified solutions will not verify, but it does seem possible that at least for a short time a slight north sea influence may mean that some north eastern parts may become cooler and rather cloudy before the high migrates slightly eastwards as the jet stream flattens the high somewhat and we start to pull in more south easterly continental sourced air once more.

 

So a settled outlook for sure, but the exact detail a little uncertain with some subtle variations from day to day quite possible

Edited October 4, 2013 by Tamara תָּמָר

[Frosty.]

The latest Fax charts show a big improvement in our weather by tomorrow as the azores high ridges into the uk with a dry and pleasant day with sunny spells and lighter winds, on sunday, a front slides slowly southeastwards from nw scotland down towards north wales and northern england with a cloudy zone but turning brighter behind it and it's the southern half of england and wales which look sunniest and warmest through the weekend and into next week with areas further north, especially n.ireland & scotland being more unsettled with fronts pushing across the north at times.

[Frosty.]

MOGREPS is going for this settled spell as well so I think we can ignore UKMO's northerly

 

@MattHugo81 

 

The persistence of pressure above 1020mb from the 12Z GFS ENS is quite remarkable - http://modeles.meteociel.fr/modeles/gens/graphe_ens4.php?x=250&y=40&ext=1&run=12&runpara=0 â€¦ - An high pressure outlook!

 

@nudeweatherman

 

@MattHugo81 MOGREPS-15 had the same signal today, maybe a tad less cyclonic week 2 as well. Looking good for a settled spell.

 

@MattHugo81

 

@nudeweatherman EC clusters have shifted that way as well generally with a far more anticyclonic pattern *almost* nationwide

That's GREAT NEWS Gavin, cheers mate

[Captain Shortwave]

The EPS members, as ever, give a bit more insight into the potential model trends than the ensemble mean and show that, whilst support is quite low, there are a few amplified solutions not too dissimilar to the UKMO this morning - so it is not a complete outlier any means

 

 

The overall agreement is for high pressure dominance, and hence the straightforward look to the ensemble means, but the exact positioning and orientation of the high pressure has taken on a little uncertainty with the trough to the north east looking sharper and likely to pull down further south from the Siberain side of the arctic than was initially modelled. This means that colder uppers seem likely to advect through north eastern, and eastern/central europe at least. It is the westward extent of this airstream that will determine conditions under the high pressure close to the UK

 

This positioning and orientation of the high will be critical as to conditions at the surface in terms of cloud cover, wind source, amounts of sun etc etc. So its one of those situations where the closer detail actually shows that the upcoming high pressure may not mean straightforward warm autumn sunshine by day after misty mornings.

 

The probabilities remain low that the more amplified solutions will not verify, but it does seem possible that at least for a short time a slight north sea influence may mean that some north eastern parts may become cooler and rather cloudy before the high migrates slightly eastwards as the jet stream flattens the high somewhat and we start to pull in more south easterly continental sourced air once more.

 

So a settled outlook for sure, but the exact detail a little uncertain with some subtle variations from day to day quite possible

Pretty much sums it up

In this mornings runs, again it's differences over in the States and Canada which causes the models to sway, the UKMO and GFS both develop a deep low over North East Canada (975mb centre) whilst the ECM is a lot less deep (around 990mb) and hence the upstream pattern is flatter and hence the interaction between the ridge over us and the ridge up the Eastern seaboard is less pronounce, this keeps heights nearer to the UK as opposed to the GFS/UKMO

For more fun the 06Z GFS is going to throw a different solution to the 00z run

Previous run

 

 

The upstream low is less deep and hence less amplification occurs resulting in an already very different day 5 chart.

GFS is going to get a south/south easterly going very quickly on this run

There we go 

Northerly on the 00z, southerly on the 06z

Edited October 4, 2013 by Captain shortwave

[AWD]

NAEFS spread at 240 hours;

Strong signal for high pressure just to the east of the UK with a warm easterly/south easterly flow. And at 384 hours;

That signal and pressure anomaly is still there. Could we be looking at an exceptionally dry October coming up? That's one strong Scandi high, oh if only it were 8 weeks later!

[Frosty.]

The Ecm 00z ensemble mean becomes fantastic, if, like me, you enjoy fine and warm weather with a large area of high pressure becoming centred over the top of the uk before slowly drifting further east, temperature wise it looks like becoming pleasantly warm and some areas turning rather warm to very warm for the time of year as warmer continental breezes gain access to the uk eventually. The bottom line is, this looks a very anticyclonic pattern on the way and it will probably last a long while, I expect today's met office update to finally jump on board properly for the first time.