Model Output Discussion 12hrs. 01/10/13

[johnholmes]

make of these two charts what you will, especially the deep vortex in the west of the chart on both models. Previously, not unlike NOAA issues, they had a deepish trough. I doubt what they show this morning will verify but we will have to wait and see. It does suggest even if it is less dramatic in reality that a form of meridional type is possible and again it is possible that the UK may be on the cold side of it this time?

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

Until the NOAA 6-10 days shows something similar I will be somewhat sceptical though.

this is its version last evening, not a million miles away mind you, less the dramatic deep vortex the two show this morning!

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

[Frosty.]

Stunning..BBC weather says strengthening Northerly winds as the week goes on, the first of many cold spells hopefully. :-)

PS...great post Lorenzo.

[phil nw.]

Certainly a cooler outlook for this coming week than was shown a couple of days ago.

That Scandi trough much more influenclal in bringing that colder air south midweek.A cut off pool of cold upper air around the near continent then could give the SE quarter quite a damp end to the week.

Not a straightforward outlook beyond with the energy split and still a weak looking jet across the Atlantic. 

Who would have thought that the often criticised UKMO T144hrs output would be the first to pick out the change? 

Edited October 6, 2013 by phil nw.

[Summer Sun]

But Gavin it does go on to say this...

Partly due to this the sixth update reduces the chance of a White Christmas. However, they remain above the long term average, especially in the south because background signals still seem to favour high pressure blocking to the north of Britain and this usually means cold weather during the winter months.

In summary the chances of snow this Christmas are thought to be above the long term average.

Only fair to give the whole picture ,dont you think??

 

This is the model thread not the white Christmas thread which is why I didn't copy it all and the computer says part offers a lot of mild weather for xmas days

[*]It's expected to be too mild for snow in the south.

[*]It's expected to be too mild for snow in Wales.

[*]It's expected to be too mild for snow in the Midlands.

[*]It's expected to be too mild for snow in the north.

[*]Cold but dry conditions are expected in Scotland

[*]It's expected to be too mild for snow in Northern Ireland.

[*]It's expected to be too mild for snow in the Republic of Ireland.

[*]Cold but dry conditions are expected in the Netherlands

Anyway after Thursday's northerly the high starts to drift east so the wind will fall light again this could increase the risk of Frost and Fog with clear calm conditions

 

 

ECM shows a similar set up though the uppers do recover but the risk of frost and fog with clear calm conditions can't be ruled out especially in the north

 

 

ECM ensemble at day 10 also keeps pressure high over the UK

 

[Summer Sun]

Latest from Gibby

 

Good morning folks. Here is the report on the midnight outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Sunday October 6th 2013.

 

The General Situation. All models are in fairly sound agreement on the course of events over the next 5 days or so. A High pressure area in the English Channel is bathing Southern areas of England and Wales in fine and dry weather today with sunny spells making it feel warm after the clearance of chilly early morning  mist and fog. Further North winds are more defined from the SW with cloud and patchy rain at times, heavy in the NW. Through the next few days the North will stay changeable with some rain at times and the South will become cloudier but still mostly dry until midweek. High pressure then is likely to transfer towards the West and NW of the UK allowing a cold front in association with Low pressure moving South to the East of Britain to bring a spell of light rain to all followed by much colder and brighter skies. This then sets up a much colder regime than we have seen thus far this Autumn with sunny spells by day but very chilly night when frost and fog become probable, more so in the North and West. The South and East may become rather chilly and unsettled by next weekend as showers from a Continental Low advances across from the East. Winds are expected to freshen too from the NE accentuating the cold feel here.

 

GFS then shows the UK remaining under cooler and more changeable conditions thereafter with the Atlantic bringing further Low pressure in to join our own home based model during Week 2 with rain at times and temperatures lower than of late. The rain could be heavy at times with strong winds locally.

 

UKMO shows High pressure up to the NE of the UK with a ridge towards Scotland next weekend. Southern England would be afflicted with a chilly and strong ENE flow with cloudy skies and the risk of a little rain at times in association with a Low pressure area over the near Continent. Mist, frost and fog would be likely in the North.

 

GEM holds High pressure closer in, over NW Britain next weekend limiting the effects of any cool NE flow over the South for a while longer before it too shows it making inroads into the UK from the East early the following week with some showers and temperatures close to normal. Cool night would result in mist, fog and a touch of frost too. that most likely in the NW.

 

NAVGEM concludes it's run with High pressure receding East over scandinavia with a ridge to Scotland weakening. An Easterly drift is shown to be strengthening over Southern britain with cloudy, grey skies likely and temperatures having fallen back to average late this week. Again mist, fog and a touch of frost are all possible by night, especially in the North.

 

ECM brings a strong ENE flow over the South at the end of the week which would no doubt feel cold under the likely cloudy skies with occasional rain as Low pressure settled close to the SE. the north would stay dry and brighter close to receding High pressure to the NE with bright days and the chance of mist, fog and frost patches by night. At the end of the run the winds have decreased as pressure has become slack over the UK with a few showers still floating around in misty and rather cloudy conditions as well as quite cool conditions too overall.

 

The GFS Ensembles show a marked drop in uppers midweek behind the cold front. thereafter a slow recovery to more average conditions at the surface look likely with occasional rain or showers following a fine start to this week. in the South. No huge amounts of rain are indicated though by any model at this range and certainly not much in the way of strong winds considering we are well into October.

 

The Jet Stream to the NW of Britain is now expected to turn sharply South over the UK midweek with a cut off Low developing close to the SE with the main flow well North of the UK over Iceland and Northern Scandinavia. There are signs thereafter this morning that it could realign much further south towards Southern Europe in week 2.

 

In Summary a change to the weather is on the way. The models were quite late in picking up this change but have now all come together in their prognosis. A cold front slipping South on Wednesday will pull in much colder Autumnal air to all areas. The North and West close to repositioned High pressure close by will become dry with the early week rain having moved away while Southern areas though dry for a while become under attack from Low pressure over Europe which looks like feeding rather cold raw and perhaps strong NE winds and occasional rain or showers. Longer term it looks like changeable conditions will ensue with not much sign of a return to the current warm uppers across Britain though it doesn't look like turning particularly chilly as yet. Nevertheless, some areas particularly in the North could see their first frosts of the season later this week but at least with the injection of drier air midweek fogs look less likely to be widespread from this morning's output.

 

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

[smithyweather]

I notice that between the runs the cold keeps getting pushed west and over me/rest of British isles with time. The 528dam touches central Scotland for a time which did not happen in 18z so perhaps in the 6z the 528dam will touch here. hmmmm

 

If it verifies we may see hill snow.

[bluearmy]

make of these two charts what you will, especially the deep vortex in the west of the chart on both models. Previously, not unlike NOAA issues, they had a deepish trough. I doubt what they show this morning will verify but we will have to wait and see. It does suggest even if it is less dramatic in reality that a form of meridional type is possible and again it is possible that the UK may be on the cold side of it this time?http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.htmlUntil the NOAA 6-10 days shows something similar I will be somewhat sceptical though.this is its version last evening, not a million miles away mind you, less the dramatic deep vortex the two show this morning!http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php

 

john, re noaa cpc output for yesterday - bin it re our little part of the NH !  i posted 24 hours ago that the ecm op solution was questionable as neafs wasnt in the lest bit interested in bringing the trough this far west and ultimately western europe as a shallow upper cold pool. the main reason for naefs being wrong was the gefs. given that on a saturday, noaa cpc is raw naefs, i wouldnt bother with yesterday's chart. todays should be a tad different although sometimes, mean charts covering 5 day periods can be quite deceptive.

 

and Crewe, re gefs being a useless tool as it is prone to flipping - ecm ens suites are often skewed towards the theme of the op. i dont recall many ecm members from fridays 12z run dropping temps to 11c this thursday in london. i'm afraid that all output has to be viewed with some caution - a lesson we should be aware of as we head towards winter. 

Edited October 6, 2013 by bluearmy

[Methuselah]

I've always been under the illusion that all of the model flip-flop past 7-10 days, most of the time...? 

[Captain Shortwave]

john, re noaa cpc output for yesterday - bin it re our little part of the NH !  i posted 24 hours ago that the ecm op solution was questionable as neafs wasnt in the lest bit interested in bringing the trough this far west and ultimately western europe as a shallow upper cold pool. the main reason for naefs being wrong was the gefs. given that on a saturday, noaa cpc is raw naefs, i wouldnt bother with yesterday's chart. todays should be a tad different although sometimes, mean charts covering 5 day periods can be quite deceptive.

 

and Crewe, re gefs being a useless tool as it is prone to flipping - ecm ens suites are often skewed towards the theme of the op. i dont recall many ecm members from fridays 12z run dropping temps to 11c this thursday in london. i'm afraid that all output has to be viewed with some caution - a lesson we should be aware of as we head towards winter. 

I think this post says things well. By all means bash the GFS over this, but frankly the ECM did little better here, it only got it right 12 hours before the GFS but a full 48 hours after the UKMO. 

How often do you see the ECM badly wrong at just 96 hours out, once in a blue moon probably. Also how often is a rogue T144 chart from the UKMO right, based on the last few months it would have to be the first one I think in a long time.

This shambles pretty much sums up the previous 2 months of model watching to a key. 

As for the output this morning, well it looks bad for the south east next week. Still no Atlantic undercut showing at the moment on any model for a week or so time. I wonder whether any model might try and play that card. The ECM day 10 chart shows some very cold air to the north east (for this time of year), if heights were to establish more robustly to our north, there might be a chance of dragging it our way. Just a thought and nothing else at the moment.

Edited October 6, 2013 by Captain shortwave

[Tamara]

john, re noaa cpc output for yesterday - bin it re our little part of the NH !  i posted 24 hours ago that the ecm op solution was questionable as neafs wasnt in the lest bit interested in bringing the trough this far west and ultimately western europe as a shallow upper cold pool. the main reason for naefs being wrong was the gefs. given that on a saturday, noaa cpc is raw naefs, i wouldnt bother with yesterday's chart. todays should be a tad different although sometimes, mean charts covering 5 day periods can be quite deceptive.

 

and Crewe, re gefs being a useless tool as it is prone to flipping - ecm ens suites are often skewed towards the theme of the op. i dont recall many ecm members from fridays 12z run dropping temps to 11c this thursday in london. i'm afraid that all output has to be viewed with some caution - a lesson we should be aware of as we head towards winter. 

Yes I think we need to be careful with revisionism. The simple fact is that no-one at all saw these changes coming.  A couple of months time, this coming week would have an air of anticipation about it, but in the first half of October it simply adds up to chilly and damp disappointment.

 

The week itself looking much more certain this morning - with a quiet and pleasantly warm first couple of days being replaced by much cooler conditions as a cold front comes south eastwards across the country midweek and then a couple of days of sunshine and showers and many eastern and south eastern parts of the UK look like receiving most of these with the driest conditions to the North West closest to the migrated High pressure.

 

The weekend is uncertain - best hope that the upper trough on the nearby continent is being over played at this distance and the High pressure starts to regain its influence once again.

Edited October 6, 2013 by Tamara תָּמָר

[Cloud 10]

Almost certainly MJO related given the difference in projection from these 2 models, UKMO very progressive here..

 

 

 

 

Plenty of support for the UKMO's phase 7 MJO prediction as we approach the middle of October,with those two blue -ve anomalies near the mid Atlantic and Russia.

 

UKMO MJO forecast..  Phase 7 composite..

 

The GFS/ECM mean height comparisons posted by JH further up the page have those anomalies,as does the ECM ensemble mean.

 

  ECM..

 

 

Looks like a more settled the further north you are scenario as we head for mid month,with the south being affected by any small euro trough,although as we have seen over the last few days nothing is exactly set in stone when it comes to model output.!!

[johnholmes]

john, re noaa cpc output for yesterday - bin it re our little part of the NH !  i posted 24 hours ago that the ecm op solution was questionable as neafs wasnt in the lest bit interested in bringing the trough this far west and ultimately western europe as a shallow upper cold pool. the main reason for naefs being wrong was the gefs. given that on a saturday, noaa cpc is raw naefs, i wouldnt bother with yesterday's chart. todays should be a tad different although sometimes, mean charts covering 5 day periods can be quite deceptive. and Crewe, re gefs being a useless tool as it is prone to flipping - ecm ens suites are often skewed towards the theme of the op. i dont recall many ecm members from fridays 12z run dropping temps to 11c this thursday in london. i'm afraid that all output has to be viewed with some caution - a lesson we should be aware of as we head towards winter.

hi baThe old chestnut re weekend, well let's wait to compare Monday with Friday before following that.It has to be said that nothing in any model output, synoptic, anomaly or anything else picked up this colder slot until UK Met T+144 came up with it.The anomaly charts have been less use than a chocolate fireguard until the last 3-5 days and even then only a little better. Their poor showing is something I have not encountered for this length of time, well over 2 weeks, since I started checking them every day over 3 years ago. No idea why the seasonal change this year has taken them so long to settle down.Just adding to this aboveI have now gone back and closely checked every anomaly chart from ECMWF-GFS and NOAA 6-10 and 8-14 back as far as those issued around 23-24 September, the 6-10 and 8-14 would cover the period of later this week and NONE, including several NAEFS I had saved suggest anything like what the synoptic models now suggest for later this week.Even with the so called failed easterly last winter, when I went back and checked 2 out of the 3 main anomaly charts then, when closely looked at, did show this, that is the non existent easterly 10 days before it did not happen, if you see what I mean! So an unusual sequence, in that none of them showed any sign of this, always assuming that the cold snap with the Scandinavai/N Sea trough does actually happen? Edited October 6, 2013 by johnholmes

[nick sussex]

The GFS 06hrs run is even more amplified than the 00hrs so now that the GFS has joined the party its determined to have a good night out.

Of more interest later on is how much energy goes underneath any blocking from that expected troughing to the west.

Edited October 6, 2013 by nick sussex

[East_England_Stormchaser91]

Wow!! Who would've thought it? This has to be one of the biggest flips I've seen yet in model watching, all 3 were nailing the warmth to continue a few days ago. So amazing to see the Atlantic still so quiet at this time of the year. Normally we would be seeing a polar vortex establishing itself easily by now. Seems as though this year it has been binned and skipped away!! 

Lack of Hurricanes are definitely playing a big part in this IMO. As a result, at the usually most active time of the year for big depressions, we are seeing unusual blocking replacing it, which is what could lead the way to a significantly cold winter I think. Never seen that much snow over Siberia and the rest of Russia this early.

[Frosty.]

always assuming that the cold snap with the Scandinavai/N Sea trough does actually happen?

I have my fingers crossed it does actually happen 

[J10]

To me an improvement to the weather pattern form next week with some Northerlies / North Easterlies, giving some decent bright sunny weather .much better than pesky South Westerlies.

Quite an an unusua; pattern though for early Ocotber, this tends to occur more often in November.

[Frosty.]

To me an improvement to the weather pattern form next week with some Northerlies / North Easterlies, giving some decent bright sunny weather .much better than pesky South Westerlies.

Quite an an unusua; pattern though for early Ocotber, this tends to occur more often in November.

Hoping the potency of the cold continues to upgrade, strengthening Northerly winds from the arctic will make a nice change.  

[Captain Shortwave]

To me an improvement to the weather pattern form next week with some Northerlies / North Easterlies, giving some decent bright sunny weather .much better than pesky South Westerlies.

Quite an an unusua; pattern though for early Ocotber, this tends to occur more often in November.

Except for the south east where they could see rain on and off for the majority of the output, in fact anywhere south of a line from Merseyside to the Humber could be susceptible to outbreaks of rain over the coming period with the low over Europe pushing bands of rain in from the continent.

For many southern and eastern areas this is a massive downgrade on conditions from potential warm and sunny southerlies to cyclonic north easterlies and outbreaks of rain. Going to be very bleak from Thursday onwards.

The 06Z GFS actually beats lasts nights ECM in terms of awfulness with the low actually re-invigorating at the end of high resolution.

I guess I should get some sandbags in preparation........

Edited October 6, 2013 by Captain shortwave

[Mr Frost]

Except for the south east where they could see rain on and off for the majority of the output, in fact anywhere south of a line from Merseyside to the Humber could be susceptible to outbreaks of rain over the coming period with the low over Europe pushing bands of rain in from the continent.For many southern and eastern areas this is a massive downgrade on conditions from potential warm and sunny southerlies to cyclonic north easterlies and outbreaks of rain. Going to be very bleak from Thursday onwards.The 06Z GFS actually beats lasts nights ECM in terms of awfulness with the low actually re-invigorating at the end of high resolution.

Just as well some of us don't live in in the South East then or South of Merseyside. :-)Glorious Autumn weather coming up IMBY. (If it actually happens of course!) Edited October 6, 2013 by Mr Frost

[Scorcher]

 

Lack of Hurricanes are definitely playing a big part in this IMO. As a result, at the usually most active time of the year for big depressions, we are seeing unusual blocking replacing it, which is what could lead the way to a significantly cold winter I think. Never seen that much snow over Siberia and the rest of Russia this early.

 

It looks like it will warm up significantly for a time though in western Russia from midweek with this pattern change- Moscow is going to be in the mid teens by Thursday by the looks of things. I wouldn't have thought this was something to celebrate in terms of winter cold prospects. If it has to be colder here I'd say keep that warm air flowing up towards Siberia!

[East_England_Stormchaser91]

Just a quick question regarding myself and other East and South-Easterners, with that low heading down the Benelux countries and into France, will there be any chance of some North Sea convection giving storms to the Eastern counties? Say E Yorks/Lincs all the way down to Kent? As we know, the sea is still warm and those uppers are going to be around 0c. Surely there will be some electrical activity possible.

 

P.S Apologies if slightly off topic.

[smithyweather]

Hoping the potency of the cold continues to upgrade, strengthening Northerly winds from the arctic will make a nice change.  

It has been upgraded since 00z.

[Captain Shortwave]

Just a quick question regarding myself and other East and South-Easterners, with that low heading down the Benelux countries and into France, will there be any chance of some North Sea convection giving storms to the Eastern counties? Say E Yorks/Lincs all the way down to Kent? As we know, the sea is still warm and those uppers are going to be around 0c. Surely there will be some electrical activity possible.

 

P.S Apologies if slightly off topic.

To be honest from the rainfall charts though not very reliable show most of the rain being of the frontal variety, hence my rather negative slant on the output. To be honest if the rainfall looked convective this might actually be quite exciting.

My question is to those celebrating further north, would you really want over 5 days of cloudy skies and persistent rain?

Edited October 6, 2013 by Captain shortwave

[smithyweather]

Just a quick question regarding myself and other East and South-Easterners, with that low heading down the Benelux countries and into France, will there be any chance of some North Sea convection giving storms to the Eastern counties? Say E Yorks/Lincs all the way down to Kent? As we know, the sea is still warm and those uppers are going to be around 0c. Surely there will be some electrical activity possible.

 

P.S Apologies if slightly off topic.

 

No uppers are going to -4c here and about -2c there.

[East_England_Stormchaser91]

No uppers are going to -4c here and about -2c there.

With the sea at around 15c, surely that will provide steep lapse rates offshore?