Model Output Discussion 19th January 2014-18z onwards.

[weather eater]

I am very confused here - I am still trying to get to grips with the models but am struggling to see how everyone on here is seeing this very wintry weather but every forecast I have seen be it the NW or Met office or TWO there is nothing really to suggest this - why are they not at least showing something close to what is suggested here yet. Sorry I know not strictly model related but I am very confused having looked at Met office and thought a downgrade but then looks like an upgrade on here.

 

 

Thanks 

No reasonably responsible weather agency or site is going to get sucked into making any kind of clear-cut forecast that an extended period of cold and snow is an odds on favourite to hit the UK starting next week, things do remain balanced on a knife edge at the moment. However there remain some encouraging signs this morning, slowly slowly the models appear to be trending that way, better in my book as we want to see the projections evolve into something decent and not appear in the mid range fully formed with the only evolution possible back towards something milder, which is the usual way of things 99 times out of 100.

Edited January 24, 2014 by weather eater

[Jayces]

I am very confused here - I am still trying to get to grips with the models but am struggling to see how everyone on here is seeing this very wintry weather but every forecast I have seen be it the NW or Met office or TWO there is nothing really to suggest this - why are they not at least showing something close to what is suggested here yet. Sorry I know not strictly model related but I am very confused having looked at Met office and thought a downgrade but then looks like an upgrade on here.

 

 

Thanks 

 

I think the fairest thing to say is that the knowledgeable posters here are posting what could happen depending on how things pan out whereas people like the Meto have to forecast the most likely outcome.

 

It's no good for the Meto saying it might snow everywhere next week if a change in the models suddenly wipes it out. They have to forecast based on the % chance of something happening and I don't think it's currently high enough for snow everywhere. Also they need to concentrate on this weekend I guess.

[snowmadchrisuk]

I am very confused here - I am still trying to get to grips with the models but am struggling to see how everyone on here is seeing this very wintry weather but every forecast I have seen be it the NW or Met office or TWO there is nothing really to suggest this - why are they not at least showing something close to what is suggested here yet. Sorry I know not strictly model related but I am very confused having looked at Met office and thought a downgrade but then looks like an upgrade on here.

 

 

Thanks 

Because the detail is not decided yet , but what seems to be getting close is the general theme of things for next week, which is looking like slider lows heading NW/SE . In general at this time of year this aids in pulling the Cold air out East further West and usually late Jan this brings Snow. long way to go but the theme looking good on nearly all models this morning .. 

Edited January 24, 2014 by snowmadchrisuk

[TEITS]

I am very confused here - I am still trying to get to grips with the models but am struggling to see how everyone on here is seeing this very wintry weather but every forecast I have seen be it the NW or Met office or TWO there is nothing really to suggest this - why are they not at least showing something close to what is suggested here yet. Sorry I know not strictly model related but I am very confused having looked at Met office and thought a downgrade but then looks like an upgrade on here.

 

 

Thanks 

Morning.

 

The simple answer is us members can afford to be less cautious than the Met O. Take todays output for example. Now for days I have been saying the Met O forecast appears out of kilter with the output and this is especially true today. What is happening in the output is the models have backed away from what appeared at first to be a brief E,ly followed by milder W,lys. The output has been trending towards a more prolonged E,ly due to the block being stronger followed by sliding LPs.

 

Take for example the ECM at +168.

 

http://www.wetterzentrale.de/pics/Recm1681.gif

 

What we have here is a low pressure moving SSE rather than W-E. This is a snow event as the fronts will be encountering cold air already over the UK but due to the track it will also pull in colder air on its N flank.

 

Another trend im beginning to see is at +240 the models are wanting to increase heights towards Greenland.

 

So in summary the main theme of todays output is a stronger block to our NE, Sliding LP systems.

[Cecil Hogmanay Melchett]

Fantastic output this morning with GEM taking top prize.

ECM looks cold and wintry as we move through next week.

All in all the meto surely have to move towards something more wintry,surely..

wow tiets,we posted at the same time,same thinking..

Edited January 24, 2014 by Cecil Hogmanay Melchett

[Nick F]

I am very confused here - I am still trying to get to grips with the models but am struggling to see how everyone on here is seeing this very wintry weather but every forecast I have seen be it the NW or Met office or TWO there is nothing really to suggest this - why are they not at least showing something close to what is suggested here yet. Sorry I know not strictly model related but I am very confused having looked at Met office and thought a downgrade but then looks like an upgrade on here.

 

 

Thanks 

 

Is quite a complicated picture as we go into next week, it has to be said!

 

Basically, all models agree on low pressure system across the UK early next week dropping into mainland Europe, a weak ridge develops to the N and NW of the UK to allow a raw northeast flow by mid-week - which should be cold enough for some snow - particularly higher ground initially - but perhaps to lower levels too. Too far off to say how far south the snow risk will be to lower levels, GFS furthest north with coldest air, EC further south with colder air. The flow looks to become quite slack once the coldest air digs in, with the UK between low pressure to the NW and to the SE and HP to the NE and SW, so without a strong cold feed, going to be marginality involved with evaporative cooling probably a big player in snow/rain margin wherever there are fronts/troughs trapped across the UK.

 

Then later in the week, low pressure is suggested by GFS and EC to slide SE across the UK, bringing another wave of cold air with potential for snow, this time from the northwest. Again GFS more reluctant to bring in the colder air than EC.

 

So, lots happening next week, with the usual suspects higher up most likely to see snow daytime, but perhaps some snow surprises at lower levels too and not necessarily confined to the north. As others have said, it's not clear cut, so forecasters will be busy!

Edited January 24, 2014 by Nick F

[Polar Maritime]

Some very snowy charts this morning with the block holding on strong, I have woken to snow cover this morning which is nice to see, lot's of surprise falls over the next week as Winter gathers momentum. As  has been said, will be nice to see the Meto update today fall in line with the output, It has been fascinating watching this unfold with such uncertainty, hopefully next week we will see plenty of surprise Snowfalls in many areas.

Edited January 24, 2014 by Polar Maritime

[snowblizzard]

Model output continues to support colder regime and possible snowy period in places for a time next week, let's hope it continues today with some upgrades!

Isobel Lang on Sky weather (ex BBC) has just said massive Scandi high with cold air looks like coming into affect UK from middle of next week! "So, big change to the feel of things next week"

Edited January 24, 2014 by snowblizzard

[Severe Siberian icy blast]

Morning. The simple answer is us members can afford to be less cautious than the Met O. Take todays output for example. Now for days I have been saying the Met O forecast appears out of kilter with the output and this is especially true today. What is happening in the output is the models have backed away from what appeared at first to be a brief E,ly followed by milder W,lys. The output has been trending towards a more prolonged E,ly due to the block being stronger followed by sliding LPs. Take for example the ECM at +168. http://www.wetterzentrale.de/pics/Recm1681.gif What we have here is a low pressure moving SSE rather than W-E. This is a snow event as the fronts will be encountering cold air already over the UK but due to the track it will also pull in colder air on its N flank. Another trend im beginning to see is at +240 the models are wanting to increase heights towards Greenland. So in summary the main theme of todays output is a stronger block to our NE, Sliding LP systems.

Yes I noticed that this morning , especially in the gem , it seems the models over estimate the strength of the vortex in fi , they always have done , and given the strength of it this year it was more believable than most , but the tide is turning , we have minor warmings continuing to hit the stratosphere over the next week and while it's certainly not a SSW I think this will have a further knock on affect in the next few weeks. With more wave 2 activity forecast in about 8 days time I believe , the -AO setting up is due to the contineous wave activity this season peeling the vortex like an onion slowly but surely , so whether people realise it or not this vortex split we have is stratospheric led , with the vortex weakening with the progression of seasons over the next few months , February is certainly looking interesting to say the least , at last ! Obviously things are never clear cut but their is tentative signs of hights from Russia/scandi moving west in time toward Greenland , which as we all know could be the wholy grail if blocking is your thing. The gem shows what could happen in the latter time frames if things go our way . But in the mid term next week is looking potentially snowy . Not too mention heavy wintry showers rattling through on a strong westerly wind Sunday nignt into Monday .

[Average Joe]

Is quite a complicated picture as we go into next week, it has to be said!

 

Basically, all models agree on low pressure system across the UK early next week dropping into mainland Europe, a weak ridge develops to the N and NW of the UK to allow a raw northeast flow by mid-week - which should be cold enough for some snow - particularly higher ground initially - but perhaps to lower levels too. Too far off to say how far south the snow risk will be to lower levels, GFS furthest north with coldest air, EC further south with colder air. The flow looks to become quite slack once the coldest air digs in, with the UK between low pressure to the NW and to the SE and HP to the NE and SW, so without a strong cold feed, going to be marginality involved with evaporative cooling probably a big player in snow/rain margin wherever there are fronts/troughs trapped across the UK.

 

Then later in the week, low pressure is suggested by GFS and EC to slide SE across the UK, bringing another wave of cold air with potential for snow, this time from the northwest. Again GFS more reluctant to bring in the colder air than EC.

 

So, lots happening next week, with the usual suspects higher up most likely to see snow daytime, but perhaps some snow surprises at lower levels too and not necessarily confined to the north. As others have said, it's not clear cut, so forecasters will be busy!

On behalf of those who don't understand the more technical references and comments on here, thank you for that very well written explanation. Much appreciated!

[Frosty.]

Before I post the Ecm 00z op run I just thought all the coldies on here would like to see the GEM 00z, it looks like one of those classic archive charts that coldies will look back on with fond memories but it's actually for next week and beyond, it's absolutely sensational, It would bring blizzards, severe drifting, ice days and severe penetrating frosts with sub -10 T850 hPa across the uk, and at least -5 or lower...the ukmo 00z is also a peach, no downgrade there..just waiting to hear something now from the television forecasters about next week..that will be the icing on the cake.  I can feel a mighty BOOM on the way.

[nick sussex]

No major dramas overnight apart from the GFS which looks a bit halfhearted, the main thing is the UKMO is still onside. Still some early differences with how the models deal with the sinking low.

 

Thereafter its down to the slider and what could possibly turn into one of the best snow events for a long time, really very unusual set up, especially as you see low pressure sliding se and deepening.

 

There looks like a good enough cold undercut on the ECM to develop snow on the eastern flank of this but at this stage where that boundary will be is up for revision, thats still not a given however because shortwave energy to the north continues to cause complications.

 

The less energy up there and the further west the block will then change which areas would be in line for that snow.

[Cecil Hogmanay Melchett]

Before I post the Ecm 00z op run I just thought all the coldies on here would like to see the GEM 00z, it looks like one of those classic archive charts that coldies will look back on with fond memories but it's actually for next week and beyond, it's absolutely sensational, It would bring blizzards, severe drifting, ice days and severe penetrating frosts with sub -10 T850 hPa across the uk, and at least -5 or lower...the ukmo 00z is also a peach, no downgrade there..just waiting to hear something now from the television forecasters about next week..that will be the icing on the cake.  I can feel a mighty BOOM on the way.

Erm,can i see that pic with the 10 out of 10 card please,its my favourite

Rampppppppppede

[ZONE 51]

Can I just show this after reading some posts about the MetO forecasts, this updated earlier..

 

 

 

Outlook for Sunday to Tuesday:

Wet and windy on Sunday. Colder thereafter, with showers or longer spells of rain, much of this turning increasingly wintry, particularly across northeastern parts. Staying windy across most areas.

Issued at: 0400 on Fri 24 Jan 2014

http://www.metoffice.gov.uk/public/weather/forecast/city-of-london-greater-london#?tab=regionalForecast

 

Expect from looking at the increasingly exciting (cold) FAX charts that an upgrade (if you like) coming soon. See no reason that this cold and snowy snap or spell.. is going to not be anything but just that! The signs been building over the last say 2 wks or so with more occluded fronts on the FAX's and the building Scandi high. Seeing such a deep low BLOCKED from entering the Northeastern territory they usually head up too then that is really quite something! 

Edited January 24, 2014 by ElectricSnowStorm

[Cecil Hogmanay Melchett]

EC Ensembles awaited,hopefully even colder than yesterday with the operational on the mild side of the mean..

[nick sussex]

The ECM preferred upstream, the GFS thought too fast and too east and the UKMO and GEM a little too slow for the period upto T84hrs.

 

HOWEVER THE 12Z ECMWF MEAN HAS TRENDED WWD FROM EARLIER RUNS ANDIS CLOSE TO THE 12Z ECMWF BY 00Z THU... AND GIVEN RECENT HISTORYIN THIS PATTERN THE GFS SCENARIO MAY BE TOO FAR OFFSHORE.  THEPREFERRED INITIAL BLEND STAYS BETWEEN THESE TWO EXTREMES WHILENUDGING THE POTENTIAL FOR PCPN OVER THE SOUTHEAST/SRN MID ATLC ALITTLE HIGHER THAN CONTINUITY.

 

That won't have included this mornings ECM but will include the GFS 00hrs output.

 

 THE 00Z GFSBY THE END OF THE PERIOD BECOMES THE FASTEST SOLN. THE 00Z UKMETIS GENERALLY THE FARTHEST NORTH THROUGH THE PERIOD AND EVENTUALLYBECOMES SLOW LIKE THE GEM GLOBAL. THE 00Z ECMWF AND 00Z NAM SPLITTHE DIFFERENCE WITH RESPECT TO LATITUDE AND WITH TIMING. THE 00ZECMWF OFFERS A VIABLE SOLN GIVEN ITS PLACEMENT IN THE MIDDLE OFTHE MODEL SPREAD WITH RESPECT TO TIMING AND LATITUDINAL PLACEMENTOF THE LOW. THE 00Z GEFS MEAN SUGGESTS THE 00Z GFS IS A LITTLE TOOFAST BY THE END OF THE PERIOD AND ACTUALLY LENDS SUPPORT FOR THE00Z ECMWF. SO...THE 00Z ECMWF WILL BE THE PREFERRED SOLN ATTMGIVEN MORE FAVORABLE SUPPORT. 

[nick sussex]

EC Ensembles awaited,hopefully even colder than yesterday with the operational on the mild side of the mean..

The ECM postage stamps do show quite a variation in the placement and orientation of that low, certainly expect to find some colder solutions than the operational run after T120hrs .

 

http://www.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2014010912!!/

 

Its clear from the ensemble mean that the operational run is one of the milder solutions!

 

We do need however the operationals to start going with the colder cluster otherwise they will eventually move over to support the  operational which is good but could be even better!

Edited January 24, 2014 by nick sussex

[snowice]

Has anybody noticed at 240h on the ECM12z the H-PRESSURE IS 1060MB.That’s going to make it hard for the Atlantic to break through, and February could spring lots of snowy surprises!

[weather eater]

Yes I noticed that this morning , especially in the gem , it seems the models over estimate the strength of the vortex in fi , they always have done , and given the strength of it this year it was more believable than most , but the tide is turning , we have minor warmings continuing to hit the stratosphere over the next week and while it's certainly not a SSW I think this will have a further knock on affect in the next few weeks. With more wave 2 activity forecast in about 8 days time I believe , the -AO setting up is due to the contineous wave activity this season peeling the vortex like an onion slowly but surely , so whether people realise it or not this vortex split we have is stratospheric led , with the vortex weakening with the progression of seasons over the next few months , February is certainly looking interesting to say the least , at last !Obviously things are never clear cut but their is tentative signs of hights from Russia/scandi moving west in time toward Greenland , which as we all know could be the wholy grail if blocking is your thing.The gem shows what could happen in the latter time frames if things go our way . But in the mid term next week is looking potentially snowy . Not too mention heavy wintry showers rattling through on a strong westerly wind Sunday nignt into Monday .

I’m not sure the models over do the PV so much as underestimate blocking, as I say things remain on knife edge, stray just a little and all shall fall to ruin, or rather I mean we remain on the milder side of any cold and thus any snow will be localised and the cold not entrenched across the whole UK.

[Troubleatmill]

Concentrating on the Azores high we have good looking postage stamps from the GEFS at T240, the majority have it displacing south or SW allowing pressure to drop in that region, vital as it allows energy to slide SE into the Biscay area.

 

One of the problems we have been seeing is that there has been (and continues to be) so much energy coming to us from the PV in the US that there has been too little room for maneuver, with the block to our east and the azores high to our SW some energy going below but too much left to our west or over us. One has to give eventually with that much energy trying to force through, you would expect the block to our east to give, but the stamps look to be going for the Azores.....  

[A.J]

very interesting model runs this morning lead me to one conclusion.........

 

"Must...........resist........urge......to.....tell.......the family.........& kids........that....snow......is.......coming......"

[Cecil Hogmanay Melchett]

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

A pretty chart if its cold you are after with a huge anticyclone over NW Russia moving westwards and a pretty significant Artic high moving out the Arctuc circle of 1040mb.

The deep purples have also drained away from Greenland.

I doubt the Atlantic will be going anywhere but SE moving forward from that.

[Trom]

I think the fairest thing to say is that the knowledgeable posters here are posting what could happen depending on how things pan out whereas people like the Meto have to forecast the most likely outcome.

 

It's no good for the Meto saying it might snow everywhere next week if a change in the models suddenly wipes it out. They have to forecast based on the % chance of something happening and I don't think it's currently high enough for snow everywhere. Also they need to concentrate on this weekend I guess.

 

Lets face it the models and the Meto were forecasting heavy rain for the South East all today, as late as yesterday, and now it looks to be dry day. 

[beng]

One of the things to watch for now over the next 48-72 hours or so (hopefully) is a gradual drop in the project 850 temps for the end of next week.  My reasoning is that I'd expect the models to begin to factor increasing European Snow cover causing a cooling feeding back.

 

Right now it looks like we've got Snow over Ukraine, Poland and East Germany - but I think this will increase from around Tuesday next week.

 

http://www.wetterzentrale.de/pics/Reursnow.html

[nick sussex]

Given the ECM ensembles and the GEFS trend I would be shocked if the UKMO didn't change their outlook to at least include more uncertainty and more possible snow.

 

If we can get the low to sink favourably and the blocking  a bit further west then it does look like even with another pulse of a stronger jet out of the USA that this could be diverted se.