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Model Output Discussions 18z 31/01/2016


phil nw.

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Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
1 hour ago, nick sussex said:

In an effort to find a window of opportunity the overall USA set up expected of amplified trough in the east and ridge in the west is one which can deliver something wintry to the UK if we could see a bit more amplitude in the Atlantic area.

The movement of the MJO could see more amplitude develop in the west Atlantic. Theres still divergence between the models especially with the GEFS which is reluctant to move this through the phases.

NCEP have however effectively disregarded the GEFS and have based their  forecast on the ECM:

Dynamical model forecasts of the MJO index support an increase in amplitude of the MJO but differ on its eastward propagation. The favored ECMWF model solution, which had better forecast skill with the previous MJO event during December 2015 through early January 2016, indicates that a strengthening MJO propagates east across the Maritime Continent during the next two weeks. Beyond Week-2, the monthly ECMWF model solution on January 29 predicts a robust MJO signal with eastward propagation across the Pacific Ocean.

We'll have to see whether the outputs can find something that includes a bit more snow and less rain over the coming days!


 

 

 

 

Nick....I always love your posts....I bloody love them!    But will you please share with me, because I haven't checked, how many times you think   the NCEP have been right in their assessments this winter....,..because to me it doesn't seem that much!!!   (but I do take on board that I'm after a result rather than a development!) 

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Posted
  • Location: Rotherhithe, 5.8M ASL
  • Location: Rotherhithe, 5.8M ASL

Just for fun - much of the UK seeing 'snowfall' on la GFS 18z tiny amounts for much of Britain but quite big depths in Scotland the ski industry will be happy - the Welsh uplands & the Pennines ect look to see a change of fortune well it has been quite barren, even knocker's back yard seeing a sprinkling I wonder how Sidney will react to that. :spiteful:

image.thumb.jpeg.6d53b6ad524d6ed0ad634baimage.thumb.jpeg.02321cc5bd212627db40e78

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Posted
  • Location: Puddletown, Dorset
  • Location: Puddletown, Dorset

Thanks for picking that chart Daniel, it shows snow for Africa but not the S Coast of UK.

Ok there is Continental climate and height ASL to consider, but even so it is interesting

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

GFS 00z gives us a colder PM flow in the more reliable which might allow for snow to low levels at times, more especially further North.

Despite conditions being stormy the really treacherous storm on the 18z has disappeared from 120 but another has popped up at 156 - it is like "thwackamole"

gfs-0-156.png?0

However because we are under colder air on this run it produces a real snowstorm for some.

gfs-2-156.png?0

And the dose is repeated a couple of days later

gfs-2-210.png?0gfs-2-216.png?016021300_0300.gif

It will very likely disappear on the next run but it does at least show the possibility of a surprise widespread snowfall event if the trough aligns itself as to give us a colder PM flow and any runner lows are further South.

Something else of note this run is that the strat warming is more prolonged and another event is signalled toward the end of the run.

gfsnh-10-384.png?0



GFS ensembles

Most runs probably keep us in a cooler/colder PM airflow out to mid term more than previously and there are a few more signs of blocking trying to develop mainly via an Atlantic ridge which allows one or two cillier runs - some more realistic than others perhaps.

p1 seems quite plausible for example although not a great deal of support.

gensnh-1-1-252.png

While p14 would certainly shake things up here, but seems far less likely. :nea:

gensnh-14-1-300.pnggens-14-0-372.png

 

graphe3_1000_256_86___.gif

Edited by Mucka
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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.

One way or another the 144-168z time frame is looking to change the game

GEM 00z following the METO medium range script of more in the way of snow then a cold short settled period

gemnh-0-210.png?00

As Mucka says GFS has a couple of runners which would bring snow for many.The first around 144-168z and a few perturbs are toying with these disturbances which may cause some surprises.

UKMO develops a feature at 144z which is as far as we can see

UW144-21.GIF?03-05

It is also becoming quite clear now that shortly after these disturbances is when our ridge will build to our west. Whilst doing so some cold /v cold air may enter the mix. Here are the GEFS

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=0&ech=240

Lets see if we , for once this winter , can get x model support on that time frame. So over to you ECM.I will be interested in the period I mentioned above.

 

 

 

Edited by winterof79
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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL

Well the ECM isn't very good for coldies , no real ridging or transient Northerlies!! Still looks very windy for Monday morning though, I'd imagine winds gusting 60-70 in the South, possibly higher in exposed places.

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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.

ECM the least desirable outcome in the latter stages,in fact its rubbish.....typical

C__Data_Users_DefApps_AppData_INTERNETEXPLORER_Temp_Saved Images_ECH1-240.gif

C__Data_Users_DefApps_AppData_INTERNETEXPLORER_Temp_Saved Images_gfsnh-0-240.png

C__Data_Users_DefApps_AppData_INTERNETEXPLORER_Temp_Saved Images_gemnh-0-240(1).png

C__Data_Users_DefApps_AppData_INTERNETEXPLORER_Temp_Saved Images_gfsnh-0-264.png

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Posted
  • Location: Edinburgh
  • Location: Edinburgh
8 hours ago, Jimmyh said:

Sorry pdiddy yes I guess imbyism is coming into play where the most populated part of the country is concerned. I didn't think my post was that imbyism I call it as I see it. Let's hope the winds are further south as we don't want this here. 

On weather front models still going for wot could turn into damaging winds. 

No worries!

I think we can all hope for downgrades to the excessive wind and rain.  GFS throws out some eye-candy for coldies at the end of the run:

MT8_Aberdeen_ens.png

 

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Posted
  • Location: West Sussex
  • Weather Preferences: Extreme cold & snow
  • Location: West Sussex

Yes please Matron :yahoo:

gens-14-1-336.png

gens-14-0-360.png

Otherwise the Op runs (GFS, ECM, UKMO) are still looking pretty unsettled and very windy in the reliable timeframes this morning.

The trend later on is looking a bit more promising - possibly.

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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk
52 minutes ago, winterof79 said:

ECM the least desirable outcome in the latter stages,in fact its rubbish.....typical

C__Data_Users_DefApps_AppData_INTERNETEXPLORER_Temp_Saved Images_ECH1-240.gif

C__Data_Users_DefApps_AppData_INTERNETEXPLORER_Temp_Saved Images_gfsnh-0-240.png

C__Data_Users_DefApps_AppData_INTERNETEXPLORER_Temp_Saved Images_gemnh-0-240(1).png

C__Data_Users_DefApps_AppData_INTERNETEXPLORER_Temp_Saved Images_gfsnh-0-264.png

Interesting to see a wedge of heights to our east/northeast trying to build towards Iceland.

then an attempt to our west a ridge trying to build north northeast towards Iceland southern Greenland!

although my towel still firmly in the ring there's slight signs of possible block of sorts.

although as u can tell by the charts in this quote the vortex much more robust and stuck over the north east of the states and Canada and another development north of the Azores although this looks to be a weak lower pressure development but nothing to developed just yet.

i suspect the vortex will continue to dominate but slight slight chance of a slow progression to perhaps a blocked Atlantic set up .

although I suspect in my opinion more Atlantic storms being produced by the big chunk vortex.

still very hard to find a crumb of something either more settled or more wintry.

 Although these pretty intense Atlantic storms are most likely to be throwing the models in lots of different directions!

so I'd be inclined to suggest fi is up until storm systems have moved on.

as we can see vast difference in last nights gfs 18z to this mornings.

but overall tiny steps of hope for coldies although certainly not of the opinion of Ian f and the settling situation mid month as without a decent Atlantic block will be very difficult to establish itself with main vortex core close to Canada Greenland area and fear that we are stuck in the vortex storm production zone.

lets hope the vortex weakens alot and sooner but as it stands not showing just yet.

 

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Apart from the obvious disappointment over the lack of any proper cold so far this season, the other thing that stands out about it is when on the rare occasion we did see the chance of some better prospects, we have never got any proper cross model agreement. This morning GFS looks promising, ECM has swung the other way, yesterday the polar opposite was true. The other frustration is that on several occasions we have seen 2 out of the 3 main models carrying a colder senario at 144, but each time they have backtracked to the milder one....and that has happened with all of them at some point. I guess in truth these colder prospects have always been 'rather longer term', so changes were not exactly unexpected, but even by the law of averages you would have though one of these colder set ups would have come to fruition. How much faith we can have in GFS over ECM this morning is frankly anyones guess, but given what has happened so far this winter the smart money is probably on a much less cold 12 GFS and a much colder 12 ECM...:wallbash:

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Posted
  • Location: Kilmersdon Radstock Somerset
  • Weather Preferences: None Really but a snow lover deep down
  • Location: Kilmersdon Radstock Somerset

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON WEDNESDAY FEB 3RD 2016

THE CURRENT GENERAL SITUATION   A cold NW flow across the UK will weaken through the day as a ridge of High pressure crosses East over the UK tonight followed by a couple of warm frontal systems tomorrow and a mild West then SW flow. 

http://www.wetterzentrale.de/pics/Rtavn001.gif

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the British Isles is around 2000ft to begin the day rising later today and tonight as milder uppers spread in from the SW taking the freezing level up to 5500ft across the North and as high as 7000ft across the South tomorrow. Some snowfall is likely over the mountains of the North tonight before turning to rain later tonight and tomorrow.

http://www.snow-forecast.com/maps/dynamic/uk

http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif

MODELS-2 WEEK HEADLINE  Mostly unsettled and windy with rain or showers. Fluctuating temperatures with some snow at times over higher ground especially in the North.

THE GFS JET STREAM FORECAST  The Jet Stream will ridge across the UK today before settling into a strong and vigorous flow across the South of Britain and France later this weekend and next week. This continues for some considerable time before the flow inches a little further North later, but every bit as strong and still blowing across the UK in two weeks time.

http://www.netweather.tv/index.cgi?action=jetstream

GFS OPERATIONAL The GFS Operational Run today shows a very volatile period of weather to come over the UK as active Low pressure areas crossing the heart of the UK deliver rain, gales and potentially stormy conditions on occasion through the next 10 days with temperatures up and down like a yo-yo as each system passes. The end of the run sees us returning to a point where we have been all Winter with Low pressure to the North and High to the South with mild SW winds and further rain at times especially by then across the North and West. 

GFS CONTROL RUN The theme of the Control Run follows a similar route with strong winds and rain featuring regularly over the next week to 10 days with some snow on Northern hills at times as colder air tucks in at times from the NW. The pattern changes are small towards the end of the run but do feature a hint of some colder air for a time before milder Westerly winds return at the end of the period in Westerly winds.

http://www.wetterzentrale.de/pics/Rtavn1441.gif

http://www.wetterzentrale.de/pics/Rtavn3841.gif

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=144&mode=0&carte=0

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=384&mode=0&carte=0

GFS ENSEMBLE DAY 14 DATA  The GFS Clusters were not available at the time of issue of my report today.

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

UKMO The UKMO model this morning shows deep Low pressure moving in across Scotland over the weekend and start to next week with strong to gale Westerly winds and squally and thundery showers embracing all Western and Southern coasts and hills, perhaps wintry on the hills and prolonged too all this following a spell of mild and eventually wet conditions leading up to the weekend.

http://www.wetterzentrale.de/pics/Rukm1441.gif

THE FAX CHARTS The Fax Charts today continue to show the unsettled theme continuing as further troughs, both warm and cold cross the UK from the West bringing rain at times and strong winds at times especially over the weekend. With deep Low pressure moving in pressure is shown to fall quickly with more complex troughing over the UK maintaining the very unsettled and windy theme continuing well into next week.

http://www.weathercharts.org/ukmomslp.htm#t120

GEM GEM today shows a wet and very windy week to come with gales and heavy rain at times from the weekend across all areas with gale or severe gales at times for all. In between the rain bands colder showery conditions will replace the rain falling as snow over the hills at times. Then towards the end of next week a cold Northerly flow develops as pressure builds North over the Atlantic and the previous deep UK based Low pressure systems move away to the East. This would bring snow showers South to all areas with the return of frost at nights under clear skies in shelter of the still brisk north wind.

http://www.wetterzentrale.de/pics/Rgem2401.gif

NAVGEM NAVGEM today also continues the windy and very volatile Low pressure based pattern with spells of heavy rain and showers crossing the UK on regular occasions over the next week with temperatures above average at first, falling somewhat later as colder air mixes into the airflows across the UK with some wintry showers over the hills.

http://www.wetterzentrale.de/pics/Rnvg1681.gif

ECM ECM today looks very windy and wet at times across all areas of the UK as Low pressure moves quickly East across Northern Britain with a strong to gale Westerly flow on it's Southern flank. The brighter air behind rain-bands will bring showers which could turn wintry over the hills at times. Later in the run signs of pressure rising again to the South and a less vigorous Westerly flow becoming more established looks possible from this run.

http://www.wetterzentrale.de/pics/Recm2401.gif

ECM 10 DAY MEAN The 10 day mean chart today indicates that things may be reverting to a less vigorous Westerly flow across the UK in 10 days time as the Jet stream begins to feed further North towards the UK as High pressure builds to the South and Low pressure displaces further to the NW too off Southern Greenland and Iceland with High pressure near the Azores and Iberia.

http://www.wetterzentrale.de/pics/Reem2401.gif

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The models continue to indicate total Atlantic domination over the period today perhaps weakening in volatility later.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.6 pts with GFS and UKMO at 99.5 pts each.  At 3 days ECM is leading with 97.7 pts to UKMO's 97.1 pts while GFS lags behind at 96.6 pts. At 5 days ECM leads with 91.0 pts to UKMO at 89.6 pts and GFS at 88.8 pts. Then at 8 Days ECM has the leading spot from GFS with 69.3 pts to 66.6 pts. Finally at Day 10 ECM is ahead of GFS at 50.6 pts to 47.6 pts respectively. 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.png

MY THOUGHTS   No real changes in the overall message from the models this morning though if I had to be picky I would say that they look overall somewhat less concerning that those that were shown yesterday and also now indicate a trend towards a less vigorous pattern developing later as pressure rises over the UK somewhat. For the here and now today's cold theme changes to mild tomorrow and Friday with mild SW winds bringing rain and drizzle in from the West tomorrow and Friday. Then through the weekend things turn distinctly unsettled and windy with gale or severe gales at times and heavy rain or showers affecting all areas. Things do turn colder with time too with showers turning wintry at times over the hills next week. The pattern then remains locked in this very windy and at times cool phase with boisterous showers which could fall as anything at times with some longer periods of rain too almost anywhere. Then as we move out of the first week and into the second week things do seem to change slightly towards less stormy and a more changeable and standard pattern as High pressure seems themed again back towards the South of the UK with Low pressure further North. While some rain still seems likely for all then too the North and West look like seeing more of this by then while the South and East see somewhat drier weather at times. Temperatures look like returning towards nearer average or a little above in the South if the High pressure to the South positions itself favourably enough. Finally today there looks very little evidence of more settled or colder weather across the UK turning up on a widespread or long lasting period over the coming two weeks, that is if this morning's output is to be used in evidence so for those wanting change in this locked Winter pattern the hunt for cold continues today.      

Next Update Thursday February 4th 2016 from 09:00

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

Using the anomaly charts, I now have had 3+ days to assess them, suggests that all 3 support the idea of a Pm type airflow from an overall westerly direction. There is continuing difference between ECMWF and GFS but NOAA remains pretty solid at 6-10 and 8-14 outputs.

Obviously they are averages and the 500mb direction will swing from about WSW to NW possibly briefly to even N in the periods. Thus a variation in surface temperatures as this occurs. No sign of any prolonged cold weather nor, using the anomaly charts, a more settled period of cold in the 14 day period.

http://www.cpc.noaa.gov/products/predictions/814day/500mb.php

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

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

The ECM is pretty awful this morning. It flattens the upstream pattern, breaks down the west USA ridge and pushes the PV and low heights east into the Atlantic.

The operational run is towards the top end of its ensembles days 9 and 10 but we really need the ECM to backtrack tonight because if the upstream flattens as the ECM suggests then its really a long way from cold at day ten.

The GFS is better with more amplitude upto T240hrs.

The GEM is the best of the outputs in terms of trend with more amplitude in the Atlantic.

Unfortunately we seem to be stuck in a rut with any more promising trends imploding the next run which I suppose sums up this winter so far.

Will something actually go right before the end of winter? I think we're now totally reliant on the MJO doing us a favour because the strat warming is not looking sufficient at present to cause enough disruption to the PV.

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Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby
45 minutes ago, johnholmes said:

Using the anomaly charts, I now have had 3+ days to assess them, suggests that all 3 support the idea of a Pm type airflow from an overall westerly direction. There is continuing difference between ECMWF and GFS but NOAA remains pretty solid at 6-10 and 8-14 outputs.

Obviously they are averages and the 500mb direction will swing from about WSW to NW possibly briefly to even N in the periods. Thus a variation in surface temperatures as this occurs. No sign of any prolonged cold weather nor, using the anomaly charts, a more settled period of cold in the 14 day period.

http://www.cpc.noaa.gov/products/predictions/814day/500mb.php

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

..... theres nothing particularly mild either

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Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset

Prize for most interesting chart of the GFS 00Z run goes to this one:

h850t850eu.png

Classic rain-to-snow event for many with plenty of precipitation around as cold uppers arrive on the scene. A correction south of the low zipping through on the 11th/12th would bring more widespread snow. It will interesting to see whether the 06Z continues this - I believe this would be a more likely/possible outcome than a full blown northerly or easterly.

By the way, what models/data are the N-W ten-day forecasts based on? The current one for my location echoes the GFS but I would guess it considers a variety of models?

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Posted
  • Location: warwick 74m. asl
  • Weather Preferences: WHITE GOLD
  • Location: warwick 74m. asl

Unfortunately we seem to be stuck in a rut with any more promising trends imploding the next run which I suppose sums up this winter so far.

This quote from you nick sums up winter 15/16 .

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44 minutes ago, MP-R said:

Prize for most interesting chart of the GFS 00Z run goes to this one:

h850t850eu.png

Classic rain-to-snow event for many with plenty of precipitation around as cold uppers arrive on the scene. A correction south of the low zipping through on the 11th/12th would bring more widespread snow. It will interesting to see whether the 06Z continues this - I believe this would be a more likely/possible outcome than a full blown northerly or easterly.

By the way, what models/data are the N-W ten-day forecasts based on? The current one for my location echoes the GFS but I would guess it considers a variety of models?

But it won't be there on the next run...and therein lies the problem of late, but thankfully we are not seeing the Dec pattern so if nothing else there is at least some hope for now.

Edited by coldcomfort
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Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset
3 minutes ago, coldcomfort said:

But it won't be there on the next run...and therein lies the problem of late, but at least we are not seeing the Dec pattern so if nothing else there is at least some hope for now.

Haha, you're probably right, or not exactly the same anyway. However, the theme of a low running through or over the southern UK next Thurs/Fri followed by a chiller settled spell has been a common theme over the last day or two. High rainfall totals would certainly be an issue for many. The main difference on that particular run was the clearance eastwards and undercut of cold air.

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23 minutes ago, MP-R said:

Haha, you're probably right, or not exactly the same anyway. However, the theme of a low running through or over the southern UK next Thurs/Fri followed by a chiller settled spell has been a common theme over the last day or two. High rainfall totals would certainly be an issue for many. The main difference on that particular run was the clearance eastwards and undercut of cold air.

Agreed, but once again it's all a week and more away. Just looked at the 06 (I still can't used to it starting at 09.30!!) and to be fair it's not a million miles away overall, but it does look like the pattern would quickly flatten again during the following weekend.

EDIT: It does and FI looks hideous as a result...back to the drawing board!

Edited by coldcomfort
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Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset
42 minutes ago, coldcomfort said:

Agreed, but once again it's all a week and more away. Just looked at the 06 (I still can't used to it starting at 09.30!!) and to be fair it's not a million miles away overall, but it does look like the pattern would quickly flatten again during the following weekend.

EDIT: It does and FI looks hideous as a result...back to the drawing board!

Yes indeed. Looks like the low is much further north on this run - perhaps the track of which won't be sorted until very close to the actual occurrence, if it happens at all lol. Equally though, FI doesn't look 'quite' as tropical as before with mild and cold air not lasting more than a day each time. Certainly changeable in an otherwise monotonous pattern. I may just have to reserve next weekend to go walking in the Welsh hills to see my snow this winter.

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

Just to add to John's post - for easy comparison of runs, you can use Meteociel's "archive" options; here is the GFS link: http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&carte=0&mode=0&archive=1&runpara=0

On to the current charts - the period 10th-12th February has been the recent focal period for cold, and the GFS 06Z shows a fairly cold set-up at this point:

gfs-0-204.png?6

Control run isn't too far off:

gens-0-1-192.png

GEFS ensemble mean is also pushing heights up to Iceland

gens-21-1-216.png

Pretty cold

222-583UK.GIF?03-6

ECM ensembles not falling over themselves in support, but some members supporting a colder period around this time

ensemble-tt6-london.gif

OK - moving from the cold to the wind - the ECM ensemble wind chart nicely demonstrates how the GFS completely overblows lows in comparison to the mean. See if you can spot the GFS 00Z on this chart (Clue: It's the one that goes off the scale at the top ;) )

ensemble-ff-london.gif

 

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Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset
56 minutes ago, johnholmes said:

Folk can take this or ignore but it might help some of you that are relatively 'new' to model watching.

Beyond about T+144 hours do NOT compare each new run to the last one, such as 06 to 00. Nine times out of 10 at those ranges you will get variations from run to run. To get some coherent idea using just the GFS or ECMWF or any other model compare like with like. Compare the 06z this morning with that from yesterday. Is there some kind of consistency? If there is then the model may be picking p a consistent signal. Then look at another time output, 00 or 12z and see if either of them are showing a similar consistent pattern. If they are then it would be fair to assume that the model at all 3 times has probably got the overall pattern correct. Detail would become more apparent as T+00 approaches. If this pattern seems to fit the overall upper air pattern that others are showing, in my case, the anomaly charts, then it is a pretty good indicator that the indicated weather pattern will evolve.

Try it over a few days to see how you feel about it.

Thanks John. This is something I've only really started to appreciate over the last six months. It's more just a bit of fun literally comparing run to run in view of what conditions might be delivered at the surface e.g. my conversation with coldcomfort this morning from an 'interest' point of view.

Taking what you say into consideration, there does look to be some agreement on a 'colder' period to come in my eyes from mid-late next week. How cold/snowy remains to be seen. Liking MWB's charts that he posted!

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