Model Output Discussion

[carnun]

Well if we are going to pull in a colder NE/E,ly flow we're going to have to rely on the LP to our SW tracking to the S.

http://www.meteociel...M1-144.GIF?14-0

However I do fear the possibility of mild SW,lys!

As do I. I see that low to the South West being renewed by another low and eventually pushing back up over us.

[cooling climate]

I don't think so CC, the pattern is all wrong to get the cold air here - that's not to say we can't get snow events over the next week, but we already have HP over Greenland with reverse zonal winds to the South, from such a set-up we are not going to get HP to the North or North East.

You know I have never rated the ECM model, lol.

Seriously I know the way I see the synoptic pattern playing out over the next two weeks or so

goes against all nwp model output at the moment but lets see how it plays out for the next

two or three days.

Just to add today was the 10th consecutive day with the AO below -4SD. Today it actually

dropped back below -5SD. The MJO is also conducive to blocking to our north and yet the best

we in the UK can achieve at the moment is a rather cold north to northeasterly airflow across the

country. Add on to this a downward propagating negative zonal winds and warming that is likely

to affect and bring blocking into Svalbard and Scandinavia and to me that spells one thing. A

freeze is coming.

Lol I have actually been looking back through archive charts with similar blocking to the north to see

what degree of cold is still possible. If synoptics developed favorably then ice days etc are easily

achievable even into March, let alone lying snow.

[kold weather]

ECM from 192hrs onwards even gts rid of the risk for Scotland, the 12z models have certainly reduced the risk of a snow event further south this suite, though ther eis clearly still a real risk further north, hopefully if worst comes to the worst at least lets get a LP over England so places further north can have some fun and games!

On another note, that LP between 216-240hrs is INSANE how tight the western side, probably get winds close to hurricane force sustained from that if that ever came off!

[Frosty.]

ECM from 192hrs onwards even gts rid of the risk for Scotland, the 12z models have certainly reduced the risk of a snow event further south this suite, though ther eis clearly still a real risk further north, hopefully if worst comes to the worst at least lets get a LP over England so places further north can have some fun and games!

On another note, that LP between 216-240hrs is INSANE how tight the western side, probably get winds close to hurricane force sustained from that if that ever came off!

Definately a less wintry trend from the 12z models which could drag us out of the winter which we have mostly loved and into a milder regime, to be honest though, this winter has been generally on the slide since mid January and this coming week might be the last of the cold for a while although it looks like fighting harder in scotland before giving up by T+192 as the ecm shows.. I hope winter can have a sting in it's tail.

[Snowyowl9]

Lol I have actually been looking back through archive charts with similar blocking to the north to see

what degree of cold is still possible. If synoptics developed favorably then ice days etc are easily

achievable even into March, let alone lying snow.

Going by an acurate thermometer it`s not easy to get an ice in March, I havn`t but I`ve only recorded with that since 2005 come close March 2006,an old reading or a car yes which read lower.

Early March 1986 was the last widespread ice day,it`s got to be easterly.

http://www.wetterzentrale.de/archive/ra/1986/Rrea00119860301.gif

Early march 1st 1995 woudn`ve been one, and one day in 1996 was below freezing,an easterly I think.

[HighPressure]

I don't normally post in here I have watched the thread over the winter, but there are signs now that winter is on the way out. We may see some snow in the South this week with some cold nights but beyond that its hard to argue with a improving picture as we will be in the last week of Feb and serious cold is going to struggle to take hold.

Its been a good winter I think its all over folks the fat lady is clearing her throat!

[full_frontal_occlusion]

For what it's worth and IMHO:

Looking at the teleconnections for some guidance, mountain and frictional torques are toying with going +ve again. AAM seems fairly static and still significantly +ve. The highly -ve AO (-5 SD) shows no signs of abating. NAO remains significantly -ve at around -4/5 and anti-correlating +ve PNA at this time, all suggest no change in the reverse zonal winds.

Looking to the now locked in ENSO pattern eastwards of Panama, SST's in the Mexican Gulf, around the Florida peninsula as far out as the central North Atlantic belt are all below long term average. Whereas in contrast, SST's into the Norwegian Sea and into the far North Atlantic are anomalously +ve.

The consequential Rossby wave thereofore looks solid for the forseeable (at least out to early/mid March) with the implication of a suppressed Atlantic with no significant short wave features to introduce S/SW incursions of milder air.

Further cyclogenesis appears more likely from the North tracking south with continued building of high pressure over Greenland.

All of this suggests the models in FI are very much over cooking Atlantic attacks.

NEasterlies sourced from Scandinavia are a distinct possibility, however those cold air incursions may well end up continuing with returning Polar Maritime air mixing with SW continental air as repeated Arctic sourced lows meander around our western shores and over us. Track is all important. Further cold and snow events a distinct possibility with short lived less cold air thrown in. Favours snow the further north one gets, but those cold front battlegrounds will keep us on our toes.

Exciting times and plenty of learning opportunities with continued unusual synoptics. The models will continue to struggle into FI.

ffO.

[damianslaw]

Long term signals in the teleconnections still support extensive northern blocking maintaining a very southerly tracking jet, the cold air from the NE has a much higher chance of enveloping us during the last week of Feb. The signals are not conducive to any sudden atlantic onslaught. The next low pressure to hit us after this meandering low this week will take a southerly course and help aid the NE flow..

Its a cold and wintry outlook right through to at least the start of March... the models when they are unsure about medium-longer term prospects always seem to default to the atlantic influence as this is the norm, this winter has not been normal at all, and this is certainly not the time of year when you expect the atlantic to suddenly fire into gear, it is the time of year when it traditionally goes into slumber and often we look to the north and east for our weather.

[Jason T]

Evening everyone, Just like to say that i think i picked the worst time ever to learn about weather models, as it appears at the moment impossible. I can easily see how you can get very frustrated to say the least.

It would be perfect if we could get some sort of an upgrade and for models to come into agreement. For most on here that are far more XP than me at this i do read all posts but even for you it seems a mind boggling past 48 hrs of runs all round.

I see some have given up on any big events happening and some calling it a day from what current models are stating,and then the others who are not convinced by model outputs.

I would like to say that even i was really hoping for a further major event just for the learning principle through the model thread so i could see how it all comes together,but even I am not that optamistic now,but i keep telling myself well it is the UK and the weather can change quickly even if the models do not confirm or agree.

So i would like to shake all your hands and say best luck for a big change on the models ,big upgrades, big event.

GOODLUCK.

[Optimus Prime]

You know I have never rated the ECM model, lol.

ECM is the most accurate so I find it slightly bizarre you show so much unlikeness for it.

[damianslaw]

I don't normally post in here I have watched the thread over the winter, but there are signs now that winter is on the way out. We may see some snow in the South this week with some cold nights but beyond that its hard to argue with a improving picture as we will be in the last week of Feb and serious cold is going to struggle to take hold.

Its been a good winter I think its all over folks the fat lady is clearing her throat!

Just want to add, take note of full frontal occlusions post... You need to look at the long term signals and teleconnections which do not support an atlantic onslaught, far from it in fact.. there seems to be a feeling that if the atlantic does start to encroach from the SW that is it for winter, all the models are being far too progressive and will likely back away from such a sceanrio in the coming days, just as they have had to do all winter. It remains very much a cold outlook for the foreseeable future.

[cheeky_monkey]

I can't work out why some members keep saying "the models are struggling" - they've been showing almost exactly the same weather for this week coming for about 5 days now, so how can they be struggling?! i.e. a mixture of rain, sleet and snow.

agreed i have been saying this for a while now..but obviously its just thee and me that think this.

[Blizzard_of_Oz]

Just watched the latest weather forecast from the BBC and they only mentioned snow for the far corner of the SE, can some 1 explain to me what the latest model runs suggest because it seems a big downgrade. The Met. Office were issuing weather warnings for many parts of the SE and EA this morning it seems a big downgrade.

So can some 1 explain the latest model run and is this where the latest forecast has came from, this is a model related post.

[bluearmy]

OP, i think CC was being sarcastic re ecm as it doesnt show a good fi on the 12z.

i have cautioned against looking closely at the models beyond T144 with the complexities of reverse zonality, shortwave phasing and MMW, IMO, the models are bound to struggle.

what does concern me re the longer term is that the 15 dayer doesnt go for cold. when the ops and ensembles trended less cold two weeks ago, the 15 dayer didnt and promised the cold would return.

[aspire27]

You know I have never rated the ECM model, lol.

Seriously I know the way I see the synoptic pattern playing out over the next two weeks or so

goes against all nwp model output at the moment but lets see how it plays out for the next

two or three days.

Just to add today was the 10th consecutive day with the AO below -4SD. Today it actually

dropped back below -5SD. The MJO is also conducive to blocking to our north and yet the best

we in the UK can achieve at the moment is a rather cold north to northeasterly airflow across the

country. Add on to this a downward propagating negative zonal winds and warming that is likely

to affect and bring blocking into Svalbard and Scandinavia and to me that spells one thing. A

freeze is coming.

Lol I have actually been looking back through archive charts with similar blocking to the north to see

what degree of cold is still possible. If synoptics developed favorably then ice days etc are easily

achievable even into March, let alone lying snow.

Having a -AO dosent mean a cold spell is heading our way. This has been explained so many times here. Again there is no real cold in the models, very disappointing again. Another week will pass waiting for a trend to cold to appear in the Models, all the while we are heading towards march.

Sorry CC, but the above post is only a hopecast.

[MagicBat]

Just watched the latest weather forecast from the BBC and they only mentioned snow for the far corner of the SE, can some 1 explain to me what the latest model runs suggest because it seems a big downgrade. The Met. Office were issuing weather warnings for many parts of the SE and EA this morning it seems a big downgrade.

So can some 1 explain the latest model run and is this where the latest forecast has came from, this is a model related post.

Blizzards,

I agree, the bbc are now going for snow in the far south east (kent) and nothing but rain in our area. Are the models going for a downgrade? To warm for snow?

Could someone explain? Have the tables turned?

[gearbox1001]

Blizzards,

I agree, the bbc are now going for snow in the far south east (kent) and nothing but rain in our area. Are the models going for a downgrade? To warm for snow?

Could someone explain? Have the tables turned?

Tables not really turned, just people reading what they want in something that clearly is not there. Some people will see some brief snow, but that's not uncommon. The majority will see rain (me included). I think March is fast approaching and this month has been a lovely end to a lovely winter. I dare say we get brief cold spells between now and March, but nothing drastic and fleeting in my opinion.

Charts and moods appear to support that this is a blip in a long line of chilly blips, also like to add, no mild spells on the way either just chilly.

[HighPressure]

Just want to add, take note of full frontal occlusions post... You need to look at the long term signals and teleconnections which do not support an atlantic onslaught, far from it in fact.. there seems to be a feeling that if the atlantic does start to encroach from the SW that is it for winter, all the models are being far too progressive and will likely back away from such a sceanrio in the coming days, just as they have had to do all winter. It remains very much a cold outlook for the foreseeable future.

I am not really arguing with that summary, I am sure the cold will not give up without a fight but we are only 14 days away from March when we will see some warmth from the sun. I am not saying the Atlantic will suddenly coming flooding back but with each day that passes its gets more difficult for the cold to hang on and I think its grip will slowly loosen over the next fortnight?

[full_frontal_occlusion]

You know I have never rated the ECM model, lol.

Seriously I know the way I see the synoptic pattern playing out over the next two weeks or so

goes against all nwp model output at the moment but lets see how it plays out for the next

two or three days.

Just to add today was the 10th consecutive day with the AO below -4SD. Today it actually

dropped back below -5SD. The MJO is also conducive to blocking to our north and yet the best

we in the UK can achieve at the moment is a rather cold north to northeasterly airflow across the

country. Add on to this a downward propagating negative zonal winds and warming that is likely

to affect and bring blocking into Svalbard and Scandinavia and to me that spells one thing. A

freeze is coming.

Lol I have actually been looking back through archive charts with similar blocking to the north to see

what degree of cold is still possible. If synoptics developed favorably then ice days etc are easily

achievable even into March, let alone lying snow.

Agree with most everything you say. I'm not disputing your synopsis but am very interested in how you arrived at the MMW resulting in Scandi blocking?

ffO.

[Blizzard_of_Oz]

Tables not really turned, just people reading what they want in something that clearly is not there. Some people will see some brief snow, but that's not uncommon. The majority will see rain (me included). I think March is fast approaching and this month has been a lovely end to a lovely winter. I dare say we get brief cold spells between now and March, but nothing drastic and fleeting in my opinion.

Charts and moods appear to support that this is a blip in a long line of chilly blips, also like to add, no mild spells on the way either just chilly.

The BBC were predicting snow for many parts of the SE and the Met.Office issued warnings for my area and now the BBC are showing and saying snow for the far SE only, what I'm asking is can some 1 give me a clear picture in what the models are suggesting now like I said its a downgrade from the BBC so can some 1 looking for the Holy Grail in the model runs please explain the very latest situation with the model runs.

Thought so I guess not?

[TEITS]

Having a -AO dosent mean a cold spell is heading our way. This has been explained so many times here. Again there is no real cold in the models, very disappointing again. Another week will pass waiting for a trend to cold to appear in the Models, all the while we are heading towards march.

Sorry CC, but the above post is only a hopecast.

No a negative AO doesn't mean a cold spell however I feel your comment saying "no real cold in the models" doesn't really tell the whole story.

What we currently have is a pool of very cold air to our N with raging E,lys spreading across Scandinavia into Iceland and then into the Atlantic. The problem for us is we need LP to be tracking to the S of the UK to allow this cold to back SW. Now it isn't as though we have LP systems blasting into Scandi with a deep PV over Greenland which is why I disagree with your comment.

The models might be suggesting that the cold remains to our N/NE but model output can change and it would only require the LP to take a different track other than NE. I honestly believe the models have a bias that blasts away any blocking and are very progressive in moving LP systems NE. Some will disagree but its almost as though our default weather patterns are programmed into these models.

So whilst a mild SW,ly might occur I remain unconvinced at the moment. Remember the +144 timeframe can change significantly in these situations as last week proved. You have to remember our current pattern is far from the norm!

Excellent post by the way FFO, I enjoyed reading that.

[FENDER.]

Its very much a case of stuck in no-mans land, neither cold nor mild, been like that for most of Feb really. The charts suggest much of the same for the next week. Very boring

[nick sussex]

Regarding the situation for snow Tuesday into Wednesday its quite a complicated set up and this chart shows why:

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=nae&MODELLTYP=1&BASE=200912201800&VAR=taup&HH=48&ARCHIV=0&ZOOM=0&WMO=

To the se over France and the Low countries the dew points are much lower and its where the front stalls and begins to push back further west that the initial snow chance is, as this front pushes back west a surface feed develops from the Continent, at the same time you have relatively cold air heading south, areas along the front with heavy precip could see this change the rain to sleet and snow but the greatest risk isn't actually where the coldest upper air is,the front is expected to weaken hence I can understand why the far se is the area mentioned as highest risk as this is likely to have the heaviest precip and greatest chance to see those lower dew points before the front weakens. However even though its only 48hrs away the boundary between the PM and continental air is still open to some change either way.

http://www.wzkarten.de/pics/brack2.gif

The fax chart for midday Wednesday shows the occluded front heading back nw, areas along the front may indeed see some rain turning to snow but it depends on how well the front holds up before weakening,in these situations you really need the heavy precip to drag the snow level down.

NOAA discussions upstream suggest in typical model fashion as soon as they sang the praises of the ECM 00hrs its 12hrs decided to go with earlier GFS runs!

12Z GFS HAS MUCH MORE OF A CENTRAL CONUS TROF DAYS 5-7 COMING MORE

IN LINE WITH THE 00Z ECMWF AND 00Z ECMWF ENS MEAN. LATEST 12Z

ECMWF HOWEVER HAS GONE TOWARDS THE PREVIOUS GFS HAVING MUCH MORE

SRN STREAM ZONAL FLOW AND LESS NRN STREAM AMPLIFICATION. A TREND

OF BOTH GFS AND ECMWF TOWARDS EACH OTHER YIELSING A RESULT THAT IF

BLENDED WOULD STILL BE CLOSE TO THE ECMWF ENS MEAN USED EARLIER.

NO CHANGES TO AFTN FINAL PROGS.

However the ECM operational run in terms of the ensembles for the Netherlands is one of the warmest solutions for days 8 to 10.

http://www.weerplaza.nl/15daagseverwachting/default_pluim.asp?r=midden

[bluearmy]

NOAA discussions upstream suggest in typical model fashion as soon as they sang the praises of the ECM 00hrs its 12hrs decided to go with earlier GFS runs!

12Z GFS HAS MUCH MORE OF A CENTRAL CONUS TROF DAYS 5-7 COMING MORE

IN LINE WITH THE 00Z ECMWF AND 00Z ECMWF ENS MEAN. LATEST 12Z

ECMWF HOWEVER HAS GONE TOWARDS THE PREVIOUS GFS HAVING MUCH MORE

SRN STREAM ZONAL FLOW AND LESS NRN STREAM AMPLIFICATION. A TREND

OF BOTH GFS AND ECMWF TOWARDS EACH OTHER YIELSING A RESULT THAT IF

BLENDED WOULD STILL BE CLOSE TO THE ECMWF ENS MEAN USED EARLIER.

NO CHANGES TO AFTN FINAL PROGS.

However the ECM operational run in terms of the ensembles for the Netherlands is one of the warmest solutions for days 8 to 10.

http://www.weerplaza.nl/15daagseverwachting/default_pluim.asp?r=midden

shame the control is in good agreement. i guess the upstream change in amplification on the ecm 12z could result in the less promising fi this side of the pond. uncertain remains the watchword. i note Dave and Tamara referring to the models from two weeks ago when they were showing the jet blasting into scandi before the ecm realised that the shortwave would slide se and the other models followed like sheep a day later. given the flip flop ecm fi's currently on offer, i'd say the behaviour of the trough towards the end of the week is very uncertain - see that word again.

time to look at the 12z NAEFS though i'm not expecting anything exciting as the GEFS have been increasingly poor re the longer term.

[johnholmes]

Well I'm getting carried away-some might say not far enough, but I've done another update on the longer term trends, looking at the usual set of charts I use for lrf outputs, anyone interested then the link is below

http://forum.netweather.tv/topic/60173-lrfs-by-jh/