Model Output Discussion

[Cheshire Freeze]

Eugene, I am not negative, I am just a realist and I am merely highlighting what may go wrong with the retrogression which is in FI. The ECM is not as good a run in the relaible as the UKMO or the GFS and I don't think may people can argue with that. Face it, the ECM is more likely to occur in the reliable time frame as was shown last night when the super dream charts of the UKMO and GFS were brought to a halt in their later outputs with the HP coming further south and that's how it stands now. If they follow the ECM again, the HP will be even further south than they show it ATM. IF that happens, who says they will follow the idea of the ECM and its retrogression.....and that's what we would be relying on to see a COUNTRYWIDE wintry spell.

Also I was actually rather optimistic WRT the last cold spell and defended the GFS over the woeful ECM. I just call it how I see it and try not to get caught up in sentiment and heartful wishes unlike some who have their fingers burnt time and time again. I don't think the weather bases itself on what people want to see

Edited February 6, 2010 by CreweCold

[TEITS]

the ECM is more likely to occur in the reliable time frame as was shown last night when the super dream charts of the UKMO and GFS were brought to a halt in their later outputs with the HP coming further south and that's how it stands now.

At the moment we cannot really say what is likely to occur. I remember back in Dec when the UKMO/ECM predicted a rather weak, slack E,ly and it wasn't until this moved into the +72 timeframe that this upgraded.

I would say the only pattern that is pretty much nailed is +72. Like I said last night there is a big difference between +72 & +120 timeframes. This might only be 48hrs but whilst the +72 timeframe remains consistent the same cannot be said for +120 especially with regards to details.

[Cheshire Freeze]

At the moment we cannot really say what is likely to occur. I remember back in Dec when the UKMO/ECM predicted a rather weak, slack E,ly and it wasn't until this moved into the +72 timeframe that this upgraded.

I would say the only pattern that is pretty much nailed is +72. Like I said last night there is a big difference between +72 & +120 timeframes. This might only be 48hrs but whilst the +72 timeframe remains consistent the same cannot be said for +120 especially with regards to details.

I totally agree, top post there. I find it amusing that when a mild breakdown to the cold is shown at 168 hours it's all 'oh well best not look beyond 96hrs as this is FI ATM' yet when cold charts featuring retrogression at 192 hours+ people are more willing to take it as gospel. The models don't work like that i'm afraid.

[J10]

Eugene, I am not negative, I am just a realist and I am merely highlighting what may go wrong with the retrogression which is in FI. The ECM is not as good a run in the relaible as the UKMO or the GFS and I don't think may people can argue with that. Face it, the ECM is more likely to occur in the reliable time frame as was shown last night when the super dream charts of the UKMO and GFS were brought to a halt in their later outputs with the HP coming further south and that's how it stands now. If they follow the ECM again, the HP will be even further south than they show it ATM. IF that happens, who says they will follow the idea of the ECM and its retrogression.....and that's what we would be relying on to see a COUNTRYWIDE wintry spell.

Also I was actually rather optimistic WRT the last cold spell and defended the GFS over the woeful ECM. I just call it how I see it and try not to get caught up in sentiment and heartful wishes unlike some who have their fingers burnt time and time again. I don't think the weather bases itself on what people want to see

Everyone is a realist from their point of view as it is how they see it. Some people are negative realists and other positive realists.

In my view, a cold spell is now pretty much certain. Much of the time, it may be dry for many areas especailly to the North and West, but I do think there is potential for some snow events in all areas from time to time. Will this event match January, maybe but probably not.

[cooling climate]

To add my pennies worth I would say the pattern is nailed to t168 whethere the high is

slightly further away allowing more unstable airflow or not is irelevent, the synoptic

pattern is pretty clear.

I would tend to agree with Teits that over the next two days or so we will see a slight

trend for the high to be held back slightly more to the northwest as I think heights will

remain that little bit higher over Greenland thus helping to support the block in the

Atlantic.

[Glacier Point]

http://www.meteociel...H1-216.GIF?06-0

Lol a bit progressive I think-

ECM 12z is always faster than the sister 00z,I think we end up with a northerly flow, but day 10 or 11 not 9...

S

Agree with this Steve.

I think there are two main considerations here, both of which increase the similarity with the December cold evolution, east flow to north-east and north.

Relative angular momentum continues to rise, reaching its highest value Feb value since 2005 (this time round colder continent and background hemispheric temps). Net contributions from the tropics, where anomalously strong west wids continue to build, place the global wind oscillation within high amplitude phases 5-6-7 which favour high pressure to the north-west. The fact that NCEP products all keep the Madden Julien Oscillation in the Pacific (phase 7/:whistling: out to20th February suggest that the global wind signal is going to get stuck in a phase favourable to blocking.

Downwelling from the upper atmopshere continus. Slight slowing as per tonight's data but typical of intermittant propagation waves, especially when the atmosphere above is still anomalously wam - no cold air to flush the warm air down. Slow and sure.

Put those together, and blocking signal becomes for retrogression from high centred north of the UK towards southern Greenland - as per previous cold patterns with notable trough solutions for Scandinavia and central and western Atlantic.

[TEITS]

Looking again at the models and it does look rather complicated for next week especially the end of the week. I shall use the JMA as an example.

Now towards the end of the week the JMA/ECM/UKMO suggest a SW tracking S down the N Sea. Now it isn't until this moves S that will pull in a colder E,ly flow although the GFS 12Z differs because we have a E,ly at +120!

http://www.wetterzentrale.de/pics/Rjma1441.gif

However even when this SW tracks S we already have upper temps around -7/8C. These drop to around -12C when the E,ly flow pulls in. I have to say im surprised the GFS 12Z didn't pick up on this because when it comes to SW I find the GFS is excellent in handling these.

So in summary there is some uncertainity with this SW and also worth mentioning the track of this may change. We could also require some patience as the much colder E,ly might not arrive until next weekend. On a more positive note even the JMA suggests the HP finally moving to Greenland.

http://www.wetterzentrale.de/pics/Rjma1921.gif

I still maintain week 2 might be even better than week 1 as I said earlier.

Edited February 6, 2010 by THE EYE IN THE SKY

[kev238]

Indeed week 1 will be a starting point- week 2 is when we could see some disruptive snowfall-- too far out for any detail though!

[lukemc]

Nothing wrong with cold frosty weather at all HD, infact it would be nice too see some sunshine! However, when you have fairly decent charts in the last few days then its sickening to see this current ECM run as snow risk is very limited. It increases later on in the run and has a decent FI but for 90% of the UK, it will be dry and that what most people in here don't want.

Still, it is cold weather and what the charts had to offer before this new trend came in was rather poor to say the least, so the output can and will change. I still think we will see some changes but it is looking less and less likely to cold snap will produce anything significant in terms of snow amounts. I also don't mean localised snow amounts, i mean more nationally.

So do you see the ECM being more plausible than the other models at the moment then? I would say even if we get a blend of the big 3 models some areas could see more significant snowfall further down the line and is it true that in these sort of synoptics snow situations can pop up at short notice e.g. a lot of people on here where saying the the January spell before it started was going to be dry; some even saying "as dry as a bone" - and look what happened then!

[Lewis]

Hi guys, not the best ECM 12Z in terms of precipitation the further North.

I'm still going with the GFS/UKMO on this one. Why? Because it was the GFS that showed this weeks ago, and it's the only model to really continue the pattern on the outputs.

If the 18z GFS is the same as last nights with regards the HP positioned much further SE, then I will maybe start to believe/favor the ECM, if it push's the high pressure further North, i think it's pretty clear whats going to happen.

Looking forward to the 18z, i'll be back for the run

Edited February 6, 2010 by Storm Force Lewis

[ANYWEATHER]

A cold pattern is certainly being established to the East of the Uk. Short term the NorthWest of the Uk looks as though it will remain cold and dry but harsh frosts at night. The rest of the Uk looks as though there will be Wintry weather, yes some snow,how much is still unknown....[Folks ],im going short term ..snow for Midlands and Eastern parts and perhaps southern central areas. [and only showers!] Remmeber this is short term and it will change! Just glad we have the cold coming through the front door, it will take its time but as [sTEVE M AND TIETS] as said it will take a time but when it comes from the back door.......watch this space

Edited February 6, 2010 by ANYWEATHER

[Frosty.]

Amazing ECM 12z for next weekend shame it's a week away but that has to be the most impressive looking Northerly I have seen for a while. The Easterly is looking a bit of a toothless affair it has to be said, although it does look cold next week but hopefully when or if the high retrogresses towards Greenland we should see something with more bite.

[nick sussex]

Well looks like I'm off to Lourdes tomorrow! those that read an earlier post will know why!

I'm quite surprised by the ECM following the UKMO as I thought the UKMO had been trying to morph into the GFS pub run!Anyway putting that aside it seems that we're having a recurring pattern in that the models prog an easterly this then gets shortened because they are already moving onto retrogression of the high to bring a northerly in, its happened several times already this winter.

So it looks like the models are evolving to a different cold set up,and yet again the easterly is really just a starter!Looking at the ECM it does however look a little too quick to retrogress the pattern, in terms of the GFS 12hrs still a very good run but the ensembles look a bit more messy in terms of that evolution so I think we're going to end up with a blend thats quicker than it but not as progressive as the ECM.

[Jason T]

Well looks like I'm off to Lourdes tomorrow! those that read an earlier post will know why!

I'm quite surprised by the ECM following the UKMO as I thought the UKMO had been trying to morph into the GFS pub run!Anyway putting that aside it seems that we're having a recurring pattern in that the models prog an easterly this then gets shortened because they are already moving onto retrogression of the high to bring a northerly in, its happened several times already this winter.

So it looks like the models are evolving to a different cold set up,and yet again the easterly is really just a starter!Looking at the ECM it does however look a little too quick to retrogress the pattern, in terms of the GFS 12hrs still a very good run but the ensembles look a bit more messy in terms of that evolution so I think we're going to end up with a blend thats quicker than it but not as progressive as the ECM.

NICK, hope you have a great time at LOURDES you poor man. ECM following UKMO who would have guessed that. ENJOY.

[bluearmy]

couple of things:

dave refers to the dec cold spell and notes that the models slackened the flow as we approached verification. this was because a scandi shortwave was progged to dive sw on the jet in earlier output and deepen, sharpening the flow. as we got below T120 down to T72, this shortwave was modelled not to deepen much and thus the flow looked slack. once we got within T72, the models started to pick up on this feature becoming more of 'a player' again and it indeed deepened markedly as it approaced the low countries, dragging in a stiff east/nor easter and delivering a decent dump.

secondly, nick s - have a look at these close in charts on ecm - any similarity to ukmo?

i see you already spotted it!! could be quite interesting if this feature does develop and swing sw as per ecm

Edited February 6, 2010 by bluearmy

[wee]

Hi guys am really sorry for posting here,but cant get on the london and south east thread,is anyone else having probs? been trying for the last 40 mins and not happening?

[Methuselah]

Hi guys am really sorry for posting here,but cant get on the london and south east thread,is anyone else having probs? been trying for the last 40 mins and not happening?

I'm not absolutely sure, wee...But try going through the Winter Discussions thingy???

[nick sussex]

couple of things:

dave refers to the dec cold spell and notes that the models slackened the flow as we approached verification. this was because a scandi shortwave was progged to dive sw on the jet in earlier output and deepen, sharpening the flow. as we got below T120 down to T72, this shortwave was modelled not to deepen much and thus the flow looked slack. once we got within T72, the models started to pick up on this feature becoming more of 'a player' again and it indeed deepened markedly as it approaced the low countries, dragging in a stiff east/nor easter and delivering a decent dump.

secondly, nick s - have a look at these close in charts on ecm - any similarity to ukmo?

i see you already spotted it!! could be quite interesting if this feature does develop and swing sw as per ecm

Yes its a lot easier to see the shortwave with those charts you posted. That could be interesting if it verifies, the UKMO certainly develops it further. Something to keep an eye on.

[LomondSnowstorm]

Yes its a lot easier to see the shortwave with those charts you posted. That could be interesting if it verifies, the UKMO certainly develops it further. Something to keep an eye on.

The UKMO also develops one a bit further north at +120 also - something to watch perhaps?

[wee]

I'm not absolutely sure, wee...But try going through the Winter Discussions thingy???

Have tried,but its only the london south east discussion that i cant get on? i can go everywhere else on the site but not there? and i want to know what ther talking about lol,sorry again for posting here ,cheers.

[Buzzit]

Have tried,but its only the london south east discussion that i cant get on? i can go everywhere else on the site but not there? and i want to know what ther talking about lol,sorry again for posting here ,cheers.

I got on to the L&SE thread a couple of minutes ago - just seems to be responding randomly....

[LomondSnowstorm]

Have tried,but its only the london south east discussion that i cant get on? i can go everywhere else on the site but not there? and i want to know what ther talking about lol,sorry again for posting here ,cheers.

I assume no one can get on as I tried to get in and it didn't work. At least you're not missing much!

Honorary membership of the Scottish one till the problem is fixed?

Anyway, to the models, and perhaps we are missing the easterly coming into NMM territory and with it snow potential for east and northern areas.

LS

[wee]

I got on to the L&SE thread a couple of minutes ago - just seems to be responding randomly....

Thanks for the reply,i can get on the thread,but for some reason cant view the last page it just wont load,anyway think i may give up for the night lol,cheers.

[Richard Lake]

Its just a server issue, I couldn't access this thread a second ago. It'll fix itself no doubt.

Edited February 6, 2010 by rikki

[Jason T]

Sincere apologises for this its the only thread ,i can barely get on. Big problems with internal server i think. Need a nw web guy to look at the problem, as you can get nw main page but getting in to threads big problem.

Help..................