Model Output Discussion - 1st February Onwards 12z--->

[Ali1977]

Sunny and frosty would be nice, this set up may give us the coldest nights of the year,especially down south.

[IDO]

Nice to see the GEFS continue the trend to lose the lower heights from Tuesday next week with the majority going for a prolonged pressure rise. Where the core heights sits remains up for debate but the most likely option by far and that has been the case for the last few days is a UK HP:

 

 

The GFS and ECM ops are notorious for over doing amplification so I am wary of endorsing the ECM yet, especially as the GFS op has corrected this morning to the usual scenario of the Atlantic ridge toppling, this time to sit over the UK. GEM has gradually reduced the amplification over the last few runs and it is similar in synoptics at D10 for the GFS:

 

 

 

Still plenty of time for flip flopping, as FI starts about 7 days away, but a UK high with winds initially from the SW from around D8-11, then the flow from the E/SE from D12-16 plus, is my view on developments. I am not seeing very cold weather from the Scandi high from week 2 of March, though way to early to be confident about that. Losing the zonality is the main benefit of the upcoming pattern change. The CFS mean for March tallies with the likely developments:

 

 

 

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS.

THE CURRENT GENERAL SITUATION A cold front will clear SE over England later today followed by a ridge of High pressure tonight and at first tomorrow before a further trough approaches the West later tomorrow.

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

MODELS-2 WEEK HEADLINE Changeable and windy at first with rain at times and hill snow across the North. Becoming brighter and drier everywhere later.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream Ensemble Forecast shows a strong West to East flow across the Atlantic through this week before it disrupts and splits North and South just to the east of the UK. The flow then weakens later in the run with the main thrust of the flow moving NE well to the NW of the UK later.

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

GFS OPERATIONAL The GFS operational today shows a very changeable week to come with spells of rain and followed by spells of colder and more showery conditions where some of these could fall wintry over the hills. Then late next week High pressure is shown to move up from the SW with fine and chilly weather with frosts at night quite widespread for the remainder of the period though cloud amounts would likely vary and the far NW could continue to see occasional rain on a SW breeze.

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

http://www.wetterzentrale.de/pics/Rtavn3841.gif
 
THE GFS CONTROL The GFS control run is broadly similar in the short to mid term but instead of showing High pressure persisting close to the UK it is shown to migrate it North later and allows cold continental air to gradually infiltrate UK air space with he increasing risk of wintry showers towards Eastern Britain later as High pressure sets up to the West and North with cold Northerlies across the UK.

THE GFS CLUSTERS The GFS Clusters illustrate a lot of High pressure in close proximity of the UK in two weeks time. The positioning of such a High is less clear with a slight preference to it being either across Southern Britain or just to the East of the UK holding preference. Only 5% of the group show any major Low pressure influence from the Atlantic.

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 UKMO this morning still shows a strong and chilly WNW flow early next week with slowly rising pressure from the SW in the final frame of the run. A rather chilly and showery period will accompany this synoptic setup.

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

THE FAX CHARTS The Fax Charts this morning continue to show an unstable Westerly flow from off the Atlantic with frequent troughs crossing the UK bringing rain and showers in fluctuating temperatures for the next 4-5 days at least.

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

GEM GEM this morning shows a  continuing spell of windy and changeable weather across the UK with rain and showers for all in alternating colder and milder phases of temperature. then towards the end of the run High pressure builds steadily up from the SW settling things down for most eventually with bright, sunny days in average temperatures but with cold and frosty nights.

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

NAVGEM NAVGEM too shows an unsettled period still to come in blustery West winds before drier and brighter weather will start to move North at least across Southern Britain by next weekend as High pressure edges up from the South.

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

ECM ECM once again this morning indicates that the prolonged spell of unsettled and windy Westerly airflow of late will come to an end next week as High pressure gains control of the UK weather. Following the spell of sometimes wet and windy weather and wintry showers in the North High pressure is then shown to ridge across the UK later next week ending up close to Scandinavia and this sets up the risk of a cold Easterly feed reaching SE Britain later perhaps with wintry showers and frosts for all by night.

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

ECM 10 DAY MEAN The 10 Day Mean Chart shows High pressure well in control across the UK and western Europe at the 10 day mark with fine and dry weather for most in light winds and temperatures held to at least reasonable levels by day.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend towards drier and more anticyclonic weather later in the period has increased to almost all output this morning from the 7-10 days range. What is also increased is the chance of High pressure near Scandinavia later.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.5 pts followed by UKM at 97.2 pts and GFS at 96.4. At 5 days ECM  continues to lead the field at 90.1 pts over UKMO at 88.4 pts and GFS at 86.7. At 8 days ECM remains the leader with 66.1 pts over GFS's 60.1 pts. Then at Day 10 ECM retains superiority at 47.1 pts over GFS at 41.1.

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.prig
 

MY THOUGHTS There is still a strong signal for High pressure to become much more influential across the UK from later next week but positioning and effects this has at the surface over the UK is very dependent on where this developing feature lies come the time. In the interim period there is still around a week of the current pattern to run with fast changing conditions in sometimes strong Westerly winds and fluctuating temperatures. It's then as we move beyond the middle of next week that pressure builds from the SW. Some output then shows this to lie over the South of the UK with benign and fine conditions with variable cloud cover. However, some output especially the GFS Control and ECM operational with some support from ensemble data show the High steadily migrating North and NE towards and eventually over Scandinavia throwing the door open for the first time this season on a cold Easterly flow to develop across the South. The GFS control run then takes this blocking High towards Greenland with further polar North winds invading the East later and no doubt snow showers should this verify. However, despite this wintry talk there is still a lot of output that shows High pressure based close to the British Isles but more benign weather over the UK with frosts at night but bright sunny days but as I'm sure all would agree a move out of the pattern that has been responsible for much of this season's weather will be a welcome change whatever change that might be. As for my final thoughts I think a period of typical early Spring High pressure will bring a spell of quiet and settled weather with the centre of High over the South of Britain but I am mindful of the increasing options of a Scandinavian High dragging cold East winds across the South later and I strongly believe with a much weakened Jet flow and other synoptic Northern hemispheric changes likely this is a possibility with time.  

Issued at 09:00 Thursday February 26th 2015

[Polar Maritime]

The GFS continues this morning to show a cool sometimes cold unsettled N/W Pm flow for the turn of the Month, As Lows push S/E over the UK with bands of rain/sleet and heavy Snowfall over the Scottish Mountains adding to some already very deep depths for the Ski Resorts up there.. By the 3/4th High Pressure pushes North towards Greenland drawing a slack cold Northerly over the UK, With signals suggesting some kind of Easterly.  

 

The GFS has been toying with this idea for a good few days now, And hopefully will firm up on detail as to exactly where the block will end up in the near future. 

 

Edited February 26, 2015 by Polar Maritime
Charts are all to cock.

[Daniel*]

E'ly is not going to have a rest. Morning ECM steady as she goes.

[stodge]

Morning all

 

Lots of permutations for the longer range positioning of the HP but in the shorter term two small depressions crossing the country as the jet turns more southerly:

 

GEM 0Z at T+78:

 

http://modeles.meteociel.fr/modeles/gem/runs/2015022600/gem-0-78.png?00

 

Would be a pell of wet and possibly very windy weather especially for the borders and northern England.

 

http://modeles.meteociel.fr/modeles/gem/runs/2015022600/gem-0-90.png?00

 

Just 12 hours later and another shallower secondary feature further south crossing the Midlands - less wind but another deluge. 

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015022606/gfs-0-72.png?6

 

From the 6Z (rolling out now) at T+72 - not a million miles from the GEM as you might expect but perhaps less windy in the specific and more windy in the general.

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015022600/gfs-0-102.png?0

 

The 0Z at T+102 so soon to be upgraded but a more significant feature than GEM with another spell of wet and windy weather likely.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015022600/ECM1-72.GIF?26-12

 

ECM at T+72 has the first depression more as a trough contained within the main LP rather than a secondary featire but the 24-hour progression (why not 6 hours like the other models) makes it hard to track the second feature.

 

It looks as though Monday and Tuesday could well be very wet and windy days for much of the country and the south in particular may face some local flooding issues before pressure rises and the fun starts (perhaps). I'm yet to be convinced of the very cold option but it's there on the table though resolution may yet be five days away.

[Winter Cold]

Still positive output on the whole this morning. The ECM is a very nice run, and as UKMO is now into the T144 range its good to see it throwing up the ridge so looks like all main 3 models do have similar ideas.

 

GFS 0z is a downgrade on last nights run, but with the 6z rolling out now, lets see where it goes.

 

Even before the easterly debate is settled, we are still on course for a very potent PM blast early next week, with very cold 850s being dragged down. In fact ECM this morning keeps England in the cold air from T120 to T240!

 

   

A few charts for example.

 

 

And then the final frame sees some lovely looking -9s over much of England. That must be the coldest air of the winter I think if it verifies:

 

 

[stodge]

The key is the evolution of the Euro trough which will ultimately "support" any higher level blocking. As the jet turns southerly and forces the secondary features into Europe the falling pressure there, combined with the amplification upstream, forces the HP (hopefully for some) to the north than north-east.

 

If the Euro-trough fails to set up strongly enough, the HP goes east and sets up over Germany (at best) or central Europe (at worst)

 

http://modeles.meteociel.fr/modeles/gfs/runs/2015022606/gfs-0-174.png?6

 

The current 6Z output - in the balance but the core of the HP perhaps too far south to ridge into Scandinavia but plenty of time for that to change.

[mushymanrob]

i dont buy it....  ill not be convinced that theres a scandinavian cold snap on the way until these charts agree.

 

 

that chart would, i think, produce a synoptic chart closer to this

 

 

then this

 

 

the noaa charts have a far better (but not perfect) track record for this period then ever changing fi charts from the ecm or gfs.

so they are either going to make a marked change as they re-adjust (which they do from time to time) or the ecm/gfs (some runs) fi scandi high solution will be dropped. and how many times this winter has these fi cold snaps come to nothing?...

[IDO]

JMA going with my expectations. Week 2 high pressure builds over the UK: 

 

I would expect temps to return to above average for most with mainly dry weather.

 

Week 3-4 anomaly and heights migrate to Scandinavia but the mean suggests nothing very cold, in fact average to above:

 

 

 

Remaining dry right through to late March. The GFS 06z continues to backtrack from the colder pattern of yesterday, which is predictable based on previous performances and bias. Am expecting ECM to also revert to closer to its mean as its bias is slowly eroded as the change comes into its more reliable period. D10 ECM mean:

 

  D14 GFS 06z: 

 

So looking like a settled March on current output. 

Edited February 26, 2015 by IDO

[Frank Trough]

I was just thinking along the lines of the above two posts (mushy and IDO, which are better illustrated than mine). I would quite like an opportunity for some snow from the east but to be honest i expect the ECM op to back away from the cold easterly scenarios over the next couple of runs. Its mean seems more in line with the general direction of travel of the other model runs which seems to be away from significant cold from the east:

 

 

 

At least the options still look drier in the medium term, especially after what could be a fairly wet upcoming period over the weekend/post weekend. 

[Ali1977]

I agree with those saying a cold snaps unlikely, no real HLB and any MLB get bowled over. Latest GFS going away from the idea also, I think by this time tomorrow we should have a better idea of where're weathers going by the end of next week...Be nice to have a high of any type, this rain is awful....and slightly depressing after the winter we've had.

Edited February 26, 2015 by Ali1977

[SMU]

the last GFS Mean runs have moved to further amplification than first thought.

 

People above forecasting the same ol same ol, may as well summise that the UK will never get any cold spell ever again. Pointless persistence forecasting if you ask me.

 

S

[Daniel*]

Yes it seems a consistent theme to underplay?

I am fairly confident the best cold spell to date meaning this winter - is in the pipeline.

Possible snow event for Monday? quite a messy picture with shortwave features. I feel if this came to fruition someone/somewhere would get buried in white stuff, the Peak District springs to mind.

Back edge snowfall for Eastern England as LP treads into low counties.

850s

Edited February 26, 2015 by Daniel*

[Captain Shortwave]

the last GFS Mean runs have moved to further amplification than first thought.

 

People above forecasting the same ol same ol, may as well summise that the UK will never get any cold spell ever again. Pointless persistence forecasting if you ask me.

 

S

Model output going for a cold easterly  - ECM operational

Model output going for UK high - ECM ens, GFS, GEFs, GEM, GEM ens, minor models (JMA/NAVGEM), anomaly charts, longer range models (JMA, EC32) and of course the metoffice forecasts.

If going with the majority model view and basing the usual ECM bias to over-amplifying the week 2 synoptics over and over again is described as pointless forecasting. Then we might as well close this thread to be honest.

 

The model output continues to suggest that March might be another one for the drier than average camp (seems to be a trend of recent Marches, both warm and cold). Where the high sets up will determine how sunny it will be and how the temperatures will pan out. Any easterly at this time of year will be below average in terms of temperatures, but again there are more likely options than cold and snowy (more likely cold and cloudy or chilly and sunny depending on the flow around the high). Of course if the high ends up over the UK or over central/northern Europe then we could see above average temperatures as the spring sun really gets to work.

 

That said, prior to this, as the Atlantic ridge builds there is a window for some wintry showers through a good part of next week as the initial westerly is pretty potent in terms of cold and the cold air hangs around as the ridge builds in resulting in shower activity transferring from western areas* to eastern coasts over time as the flow veers to the north.

 

*The initial west/north westerly may bring more widespread wintry showers if home grown convection can kick off.

 

Summed up nicely by Daniels charts actually, we might be looking at the wrong timeframe. Chasing the easterly and ignoring the potential wintriness from the west/north westerly preceding it. I can't say that lying snow will be likely but if there are some beefy showers, then it is perfectly plausible that precipitation could fall as snow and provide transient accumulations if it is heavy enough.

 

Final edit - GFS ens for the 06z are out, looks like a continental south/south easterly will set up at the later stages of week 2 and into week 3, in line with the JMA forecast. Probably a dry, sunny and chilly set up.

Edited February 26, 2015 by Captain shortwave

[mushymanrob]

the last GFS Mean runs have moved to further amplification than first thought.

People above forecasting the same ol same ol, may as well summise that the UK will never get any cold spell ever again. Pointless persistence forecasting if you ask me.

S

Of course the uk will get a cold spell again and when one is seriously on the cards and supported across the board then i and others will post accordingly. the uk's weather is often 'somewhere in the middle' (or same ol same ol) . look how many times this winter chart that far out show a cold spell only for it to disapeear closer to day 1.

i dont buy it (YET) because i trust the noaa charts as being the most reliable in suggesting what the upper flow will be. (following on from john holmes's observations ). all winter weve had pattern changes here, pattern changes there, and non have become reality. but the accuracy of these noaa charts has been quite remarkable, only once that i can recall have they had to make a sharp adjustment. the rest of the time they have been spot on.

so in my very humble opinion, ill stick with what they predict, knowing that most of the time theyll be accurate, but not always and the scandi high MIGHT yet occur and give us all a frosty cold (but dry) spell.

Edited February 26, 2015 by Polar Maritime
To move discussion on..

[IDO]

The GFS snow accumulations for the next 8 days show that the westerly favours the usual suspects:  

 

Temps are not too bad for the south as a whole, just below average, though I suspect they will feel cooler when the colder uppers blow through early next week.

 

The 06z D16 mean remains very promising for a prolonged dry period:

 

 

[legritter]

Yes we have some nice charts today IF its cold weather your keen on .But i,m fast becoming a stickler  for Met office outlook and not looking to far ahead as the weather at Ten days or so ahead can be very hard to predict with the charts We have available .

Mushymanrob on post 1475 mentions NOAA I too find their site interesting .But what is interesting at the moment for me is the fact that going back a week or so ago it looked like high pressure would move in and set up shop in a position bringing us mild dross .

And here we are in a Possibility of possibly seeing high pressure eventually to our north or north east .when i first joined Net weather ,i would watch Gfs every run and must admit would run with some of the Pack chasing every available cold chart only finishing up completely emptying my pram ,A great Forum and great learning site ,and i,m pretty sure the best on offer and its FRee ,catch up with you all later for tonights eye candy i hope ,cheers   

[johnholmes]

the last GFS Mean runs have moved to further amplification than first thought.

 

People above forecasting the same ol same ol, may as well summise that the UK will never get any cold spell ever again. Pointless persistence forecasting if you ask me.

 

S

 

Unkind and unfair Steve, if they provide charts to illustrate their viewpoint. All of us are entitled to our viewpoint if it is backed up by charts and for others to refrain from 'having a dig' if it does not fit with a cold perspective.

 

my own view based as usual on the 3 anomaly charts and for 6 days onwards not the next 72 hours

 

Differences between them continue;ec suggests a colder outlook than previously while gfs looks almost to be suggesting similar; there is little consistency with either of them. So until noaa 6-10 shows something similar, which last evening it did not, and we have at least 2 outputs subsequent to that from ALL 3 then doubt must persist as to just what the upper flow may be in 6-10 days time. There does seem to me looking closely every day at these 3 outputs a suggestion of some kind of upper ridge developing centred on or east of the meridian. If the EC version occurs then a cold spell could, note, could develop. We should have a better idea in 48-72 hours. That is beyond the cold following behind today’s’ low and another one through the weekend. Certainly some interest for weather fans and perhaps more so with a cold inclination than those wanting mild

Edited February 26, 2015 by johnholmes

[Snowman.]

I'm not surprised with the possible indication in March as the CFS spotted this two months ago and it is still here today.

 

 

 

 

 

 

Many find the CFS useless but this signal and consistency is amazing.

 

Since around the end of December it showed two re-accruing things. With 3/4 runs showing synoptics that could deliver.

 

1 - A cold march

2 - Above heights North/North-East of the UK.

 

What's beginning to trickle its way into the current output.

 

A cold march and heights North/North-East of the UK.

 

These things can't be ignored simply because there is very little support inside the main models. I stick by the CFS as I believe it is onto something here.

 

The CFS also picked March 2013, now I'm not saying that we can get a repeat but still a cold march may be in order.

 

I shall now retreat back to the shadows and stay away from this thread but will continue to look at the models. Just remember if this happens it was the "useless" CFS that spotted it first.

 

 

Have a nice day.

Edited February 26, 2015 by SN0WM4N

[Captain Shortwave]

The GFS builds heights over the UK by day 7

 

GEM for the same time

After some blustery wintry showers on Tuesday and Wednesday it will dry up and become sunny with frosty nights (maybe a few scattered showers for a time in the east). The GFS follows up with a north/south split as weak fronts push through Scotland, the GEM keeps the high centred over southern England and would deliver pleasant spring time conditions with sunny spells for most by day and chilly nights with frost in places.

Still out of the range of the UKMO at the moment, it's day 6 chart showing a showery north westerly flow.

 

GFS for comparison

Edited February 26, 2015 by Captain shortwave

[IDO]

Too far out to be confident but very Spring like weather from the GFS 12z from around D10:

 

D11 D12

 

UK HP in charge from around D7 to D16, and it continues to correct its earlier over amplified Atlantic ridge runs. GEM is very similar at D10:

 

 

Expect ECM to correct accordingly later.

 

Dr Cohen's latest blog: https://www.aer.com/science-research/climate-weather/arctic-oscillation

 

Offers little prospect of any late cold wintry spell for our region, with any cold pools continuing to be favoured as per this winter's repeating pattern.

Edited February 26, 2015 by IDO

[Daniel*]

ECM is cold dominated except from the final frame when Azores High starts to build in, turning milder from the west there will be snow opportunities on this run too. It is not a HP fest especially for the east. GFS seems overly progressive, I'm going with ECM on this. I'm astounded by how quiet it is considering.

Edited February 26, 2015 by Daniel*

[Winter Cold]

ECM is cold dominated except from the final frame when Azores High starts to build in, turning milder from the west there will be snow opportunities on this run too. It is not a HP fest especially for the east. GFS seems overly progressive, I'm going with ECM on this. I'm astounded by how quiet it is considering.

image.jpgimage.jpgimage.jpg

image.jpgimage.jpgimage.jpg

 

Yep its another beauty of a run for me! was just going to post the same thing. Plenty of snow chances id say, the really cold upper air and stronger sun should set off some nice snow showers I hope.

 

GFS has been poor today for coldies, moving away from the scandi high solution. Weve seen it move away from a scenario many times though after being the model to pick it out and then return to it later so its not all over yet!

[Milhouse]

ECM is cold dominated except from the final frame when Azores High starts to build in, turning milder from the west there will be snow opportunities on this run too. It is not a HP fest especially for the east. GFS seems overly progressive, I'm going with ECM on this. I'm astounded by how quiet it is considering.

 

Probably because most have noticed the cold easterly in FI has now been replaced by the onset of milder Atlantic air. No one can be sure of anything when there has been such a shift in the space of 24 hrs.