Model Output Discussion

[graupel]

ITS FI , not F1... it's not a grand prix chart watching contest!

Besides i'm waiting till atleast friday to see if we get this nailed or not , awaiting the 18Z

And it all started with an innocuous little area of high pressure over northern france ridging northward - january 18th 1946, couldnt resist it B) Ten days later

[NorthNorfolkWeather]

A couple of points.

First, it looks b^&**y cold next week, especially in Copenhagen (plug for the competion in the World General Discussion Forum) But Lake Effect Snow could be a problem in many eastern areas from late Monday onwards

Secondly, From the (late FI) what are the chances of a Polar Low from this?

As I understand them they are convective mesoscale systems. This cold is happening early, North Sea is VERY warm compared to the 'normal' time we'd get this.

Whoops sorry ramping

Arghh where's the piccy? Answer next post but one down

It's supposed to be the T+384 GFS 850's +SLP

Edited December 9, 2009 by NorthNorfolkWeather

[Geordiesnow]

I'm also like a few others not going to get carried away with the current charts, it's all a little too far out and as PP says, the models have not decided how to handle the shortwaves. Also note that we could end up what the JMA is showing and i'm sure some could well be disappointed if something like the JMA is showing occurs.

I said a few days ago today/tomorrow output may give me more confidence if we get a cold/snowy spell but i feel this will have to be put back until the weekend at least so this shows that the proper snow potential has been put back. Although to be fair, as i said loads of times, only a few runs have shown a full blown easterly in the 180 hour timeframe recently so i suppose this could potentially be the big test.

Also remembering that the GFS 06Z run shows how snow potential can be very limited thanks to those shortwaves so a snowy spell for the UK is far from certain.

[NorthNorfolkWeather]

try this

see the post but one above

Edited December 9, 2009 by NorthNorfolkWeather

[bluearmy]

I'm also like a few others not going to get carried away with the current charts, it's all a little too far out and as PP says, the models have not decided how to handle the shortwaves. Also note that we could end up what the JMA is showing and i'm sure some could well be disappointed if something like the JMA is showing occurs.

JMA is fabulous ???? have you an old run in your cache ?

try this

not sure that the chart you showed is what you wanted to NNW as there isnt even a polar flow. also, pretty pointless to ask about detail on a chart two weeks away. look at the output a week away - its much more interesting and far more likely

[Optimus Prime]

Yeah the JMA is probably the best run out of them all for wintryness.

I do find the 25th December charts interesting...I can all but hope.

[snowlover2009]

Makes me laugh in here, people telling people to calm down. what do you want us to do, turn are noses at the charts when they are absolutly superb and so much agreement even if the models are suggesting different places on where the really cold and snowy stuff will be in the uk, there is some of the strongest agreements i have ever seen on these charts for a potentially very cold and snowy spell. if we didnt discuss it, then we would have people moaning at us asking why we aint speaking about it, so we can not win. we are allowed to get excited and i will get exicted because that is the way i feel. it would take a lot now to go back to square one with the mild atlantic weather after all these exceptionally good runs. and i agree stop calling it f1 its bloody annoying.

[Snowaddict]

Hi SA,

How do you think things are shaping up for us in Ireland. Great charts again today,im starting to get really excited i must say. Great potential for a great cold spell the like we have not had for many a year.

Hi Sundog.

Well, as ever with any cold spell that originates from the variable east, eastern, northeastern and southeastern areas will have the best chance of seeing some snowfall.

However, Ireland would be a good T+16 to T+24 hours behind the UK in receiving such snowfall as the cold upper air would need to successfully back west...

If the setup as modelled on tonight's ECMWF or other guidance does indeed occur I would expect snowfall off the Irish sea, with the possibility of more sustained outbreaks from embedded troughs in the flow..

In addition, if the cold air becomes entrenched enough across the British Isles, southern areas of the country in particular would be at risk of a significant snowfall even if fronts were to approach from the Atlantic. In fact, all areas would be at risk of frontal snowfall if the cold air was deep enough and became entrenched for long enough.

Overall, I'm very pleased with the latest NWP guidance, however I would say that caution is still very much advised.

For example, if the GFS evolution was to occur we would be at risk of flurries early next week, however it would be mid week before snow would arrive in line with the ECMWF evolution.

Unfortunately it's too early regarding snow etc but the general idea of cold, potentially sustained and severe cold, has strong credence tonight...

By next Sunday into Monday it should begin to feel rather cold.

Just think, with so many fields flooded after the weeks of rainfall we may have quite a few frozen landscapes around if the latest output were to verify.

SA

Edited December 9, 2009 by Snowaddict

[snowlover2009]

Yeah the JMA is probably the best run out of them all for wintryness.

I do find the 25th December charts interesting...I can all but hope.

which charts are you talking about?

[NorthNorfolkWeather]

not sure that the chart you showed is what you wanted to NNW as there isnt even a polar flow. also, pretty pointless to ask about detail on a chart two weeks away. look at the output a week away - its much more interesting and far more likely

I wasn't talking about the south, talking more of Scotland, and yes, it is two weeks away, it is FI, it will change.

But once in a while.....

[bluearmy]

now we have x model agreement, none of the output should be dismissed re the likely path of the shortwaves. i recall it was GME which first spotted that our frigid shortwave in early feb was going to set up shop in the sw approaches after it had passed through the south of the country.

[LomondSnowstorm]

I'm also like a few others not going to get carried away with the current charts, it's all a little too far out and as PP says, the models have not decided how to handle the shortwaves. Also note that we could end up what the JMA is showing and i'm sure some could well be disappointed if something like the JMA is showing occurs.

I said a few days ago today/tomorrow output may give me more confidence if we get a cold/snowy spell but i feel this will have to be put back until the weekend at least so this shows that the proper snow potential has been put back. Although to be fair, as i said loads of times, only a few runs have shown a full blown easterly in the 180 hour timeframe recently so i suppose this could potentially be the big test.

Also remembering that the GFS 06Z run shows how snow potential can be very limited thanks to those shortwaves so a snowy spell for the UK is far from certain.

I think we're clutching at straws when we're relying on yesterday's JMA (see below for today's one) for a down to earth view - what next, hauling the old WMC out ?

Also, I'm not sure if the cold has really been put back all that much, as the first snow showers were shown a few days ago for Sunday/Monday and there does seem to be the potential for wintryness on Sunday, at least in the south east, before the real cold comes in on Tuesday evening.

[Tom Quintavalle]

After the euphoria of the 12zs, I totally agree with the above posters, this is far from a "done deal" yet. It looks like the trigger low that is expected to run south down the N.Sea, that eventually unleashes the real cold, doesnt arrive till Weds at the earliest.

http://charts.netweather.tv/gfsimages/gfs.20091209/12/171/h500slp.png

http://212.100.247.145/ecmimages/20091209/12/ecm500.192.png

http://www.wetterzentrale.de/pics/Rjma1681.gif

http://91.121.94.83/modeles/nogaps/run/nogaps-0-168.png?09-18

IF these scenarios are still being shown Sat/Sun (t96/t72), then I will feel a lot more confident at the prospect of a decent cold spell with snow for many areas. So that leaves us around 3 to 4 days to get through and us we know from bitter experience, thats plenty of time for things to pear-shaped.

As has been stated to get cold to back far enough west across the U.K, all the jig-saw pieces have to slot into place, much more than say for Cent./East Europe, who have the cushion of a cold land-mass in their favour.

The analogy has been made before, we are near the end of the line for the Polar Continental Express. I just hope that this particular service doesnt behave like some London bus routes, you wait and wait for a service thats been delayed, only to realise thats its been curtailed short of its journey and sent back from whence it came!

Regards,

Tom.

[jonathon]

I think we're clutching at straws when we're relying on yesterday's JMA (see below for today's one) for a down to earth view - what next, hauling the old WMC out ?

Also, I'm not sure if the cold has really been put back all that much, as the first snow showers were shown a few days ago for Sunday/Monday and there does seem to be the potential for wintryness on Sunday, at least in the south east, before the real cold comes in on Tuesday evening.

yeah i saw that

[Eugene]

lol not sure what geodiesnow is on about GFS 06Z was a snow making run, i assume he must mean the GFS 12Z and then he mentions JMA which is great tonight also i would say the runs are great tonight with the faulty looking UKMO 00Z being corrected on 12Z so every model is aboard now so what more do you want people.

[Cecil Hogmanay Melchett]

ECM ens are not all that great.There is huge uncertainties here guys.

I was hoping for uniformity but no sign of it.

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

Edited December 9, 2009 by happy days

[LomondSnowstorm]

18Z about to come out, let's make it a clean sweep with every run today, barring the 00Z UKMO possibly, showing a cold and snowy spell next week.

[ribster]

ECM ens are not all that great.There is huge uncertainties here guys.

I was hoping for uniformity but no sign of it.

http://www.knmi.nl/exp/pluim/Data/PLUIM_06260_NWT.png

I think you're in cloud cuckoo land if you thing you are going to get absolute uniformity across all models, with them singing from exactly the same hymn sheet. Perhaps you would be happier if we were being battered with south-westerlies? The general theme is there or there abouts, what we get from it is as yet unknown.

[Geordiesnow]

Thanks to those who corrected me regarding the JMA run, i'm not sure what the PPN charts would be on the JMA 192 hour chart and seeing as the easterly flow gets cut off by a shortwave, i probably jumped the gun and thought it was "bad".

In responce to snowlover2009's post, theres nothing wrong with getting excited but when you have posts saying that a snowy spell of weather is certain, then you know we have to remind people that it is far from certain and take a step back a little bit. Plus the over ramping posts are mis-leading to those who may not know how to read the models.

lol not sure what geodiesnow is on about GFS 06Z was a snow making run, i assume he must mean the GFS 12Z and then he mentions JMA which is great tonight also i would say the runs are great tonight with the faulty looking UKMO 00Z being corrected on 12Z so every model is aboard now so what more do you want people.

06Z run showed a very slow shortwave making Southwards i recall, it's not too bad of a run but the easterly flow i seem to recall was rather slack consequently not the coldest run one will ever see.

In terms of your last line of your post, i want to see these nice cold snowy charts going from 168 hours to under 120 hours, then i might start to get a tad excited. No good having all those nice cold snowy charts at 168 hours because they will more than likely to change.

[Harsh Climate]

Thanks to those who corrected me regarding the JMA run, i'm not sure what the PPN charts would be on the JMA 192 hour chart and seeing as the easterly flow gets cut off by a shortwave, i probably jumped the gun and thought it was "bad".

In responce to snowlover2009's post, theres nothing wrong with getting excited but when you have posts saying that a snowy spell of weather is certain, then you know we have to remind people that it is far from certain and take a step back a little bit. Plus the over ramping posts are mis-leading to those who may not know how to read the models.

06Z run showed a very slow shortwave making Southwards i recall, it's not too bad of a run but the easterly flow i seem to recall was rather slack consequently not the coldest run one will ever see.

In terms of your last line of your post, i want to see these nice cold snowy charts going from 168 hours to under 120 hours, then i might start to get a tad excited. No good having all those nice cold snowy charts at 168 hours because they will more than likely to change.

I agree, while the snowy charts are past 120h we have absolutly no guarantees. Inside 120h then we can get excited

[snowlover2009]

Thanks to those who corrected me regarding the JMA run, i'm not sure what the PPN charts would be on the JMA 192 hour chart and seeing as the easterly flow gets cut off by a shortwave, i probably jumped the gun and thought it was "bad".

In responce to snowlover2009's post, theres nothing wrong with getting excited but when you have posts saying that a snowy spell of weather is certain, then you know we have to remind people that it is far from certain and take a step back a little bit. Plus the over ramping posts are mis-leading to those who may not know how to read the models.

06Z run showed a very slow shortwave making Southwards i recall, it's not too bad of a run but the easterly flow i seem to recall was rather slack consequently not the coldest run one will ever see.

In terms of your last line of your post, i want to see these nice cold snowy charts going from 168 hours to under 120 hours, then i might start to get a tad excited. No good having all those nice cold snowy charts at 168 hours because they will more than likely to change.

yes i agree.

this for example in a way is an absolutly crazy post tbh

'I've mentioned in another thread but will do so one more within the Model output, that Snow will fall and settle and that

is 100% guarenteed, most especially in the North east, the east and again the south east. The pre christmas period will see

a good fall, followed by shall we call it a lul in the weather during the 24 - 28th before bitter cold weather and once again

snowfall arrives in the east and most especially south east, in fact the post Christmas snow could be a lot heavier and possibly prolonged for the east and south east. Look to the 28th Dec for the onset of the next snowy cold spell. and 16/17 to 20th for the first snowy spell. Again this is not a matter of doubt, the models are for once correctly predicting what

will be the outcome. For snowlovers, a real feast awaits you within 10 days !

Cheers

PE '

anyone agree

18z rolling out now i cannot wait, pub run of all pub runs.

[Harsh Climate]

yes i agree.

this for example in a way is an absolutly crazy post tbh

'I've mentioned in another thread but will do so one more within the Model output, that Snow will fall and settle and that

is 100% guarenteed, most especially in the North east, the east and again the south east. The pre christmas period will see

a good fall, followed by shall we call it a lul in the weather during the 24 - 28th before bitter cold weather and once again

snowfall arrives in the east and most especially south east, in fact the post Christmas snow could be a lot heavier and possibly prolonged for the east and south east. Look to the 28th Dec for the onset of the next snowy cold spell. and 16/17 to 20th for the first snowy spell. Again this is not a matter of doubt, the models are for once correctly predicting what

will be the outcome. For snowlovers, a real feast awaits you within 10 days !

Cheers

PE '

anyone agree

18z rolling out now i cannot wait, pub run of all pub runs.

Mate if you can predict whats guna happen after the 28th december Leeds are guna win the FA cup.. Every model is struggling past 5 days, the truth is nobody knows whats guna happen. Lets just hope we get lucky this time!

http://www.wetterzentrale.de/pics/Rtavn662.png

Out to 66h, a better draw of cold air into Russia but less WAA into greenland, lets see how this turns out.

[SLEETY]

Mate if you can predict whats guna happen after the 28th december Leeds are guna win the FA cup.. Every model is struggling past 5 days, the truth is nobody knows whats guna happen. Lets just hope we get lucky this time!

Despite the fact every single model is showing virtually the same output past 5 days ,never seen such model agreement before regarding a cold spell

What models are you looking at then

Edited December 9, 2009 by SLEETY

[LomondSnowstorm]

Mate if you can predict whats guna happen after the 28th december Leeds are guna win the FA cup.. Every model is struggling past 5 days, the truth is nobody knows whats guna happen. Lets just hope we get lucky this time!

To be honest the models have been far more consistent lately than I think I've ever seen them, with the gfs parallel in particular having shown roughly the same outlook for days now. As many experts on the forum have already said, the building blocks are in place, with only a few details to work out. When JH says he is 90% certain of this cold spell, with as good model support as we could possibly expect, I think people have a right to get a bit excited about what are, after all, exceptional charts. After all, it's what most model watchers have been looking for since they first started model watching! Although it still could all fall apart, I think it is more likely than not to happen.

LS

[wysiwyg]

Despite the fact every single model is showing virtually the same output past 5 days ,never seen such model agreement before regarding a cold spell

What models are you looking at then

I think the statement relates to the fact that model output over the last few days has changed (flip-flopped in some cases) post 5-days. They may well continue to do so and today may just be one of those days when they all align and agree nicely on the same run (based on how the models compute data - rare I would say)

Tomorrow could see a return to disagreement. I hope not.

Edited December 9, 2009 by wysiwyg