Model Output Discussion

[snowlover2009]

No need to swear in nearly every post you have made tonight, i thought last night you said you understand the charts??

Lewis

i am sorry but it seems you want to start an argument with me.

firstly i do understand the charts

secondly the only swearing in their is crap and if i swear it is usually mild.

edit: thirdly you said you would ignore me so why are you doing the opposite. don't waste you time saying things then asking a question what does not make sense to what i have said previously.

finally what on earth are you getting at by asking me if i understand the charts. If you are talking about the missing data then i presumer you think i don't understand this. well who does? stop been so picky you made it clear last night you would ignore me. so please just do that instead of asking me a question what doesn't exactly makes sense to what i said in that quote.

What`s wrong with charts like this I must be missing something.

http://91.121.93.17/pics/Rukm1201.gif

http://91.121.93.17/pics/Recm1441.gif

http://91.121.93.17/pics/Recm2161.gif

They`re brilliant,mild air is struggling you have to remember that,not doom and gloom posts.

its people in the sfar south moaning and groaning in particular. they forget the snow would still fall somewhere further north.

Edited December 26, 2009 by snowlover2009

[Harsh Climate]

i am sorry but it seemsyou ant to start an argument with me lol.

firstly i do understand the charts

secondly the only swearing in their is crap and if i swear it is usually mild.

thirdly what on earth are you getting at by asking me if i understand the charts. If you are talking about the missing data then i presumer you think i don't understand this. well who does? stop been so picky you made it clear last night you would ignore me. so please just do that instead of asking me a question what doesn't exactly makes sense to what i said in that quote.

its people in the sfar south moaning and groaning in particular. they forget the snow would still fall somewhere further north.

Im afraid the south look like taking a hit of rain and mild tue/wed for us to see snow... A small price I would be willing to pay...

[snowlover2009]

Im afraid the south look like taking a hit of rain and mild tue/wed for us to see snow... A small price I would be willing to pay...

yes i know. but why would we have a price to pay, unless you just mean that the south would just have to be hit with rain lol.

[keithlucky]

Im afraid the south look like taking a hit of rain and mild tue/wed for us to see snow... A small price I would be willing to pay...

Not what rob mackelwee said 3 days of snow m4 northwards.

[snowlover2009]

I but they will get there chance when the lp slips south east all get snow everybody happy, then a n eastly to follow

yes that is right. but rain at first for the far south at least i think, then snow larer as it falls south. so people shoudln't be too disappointed.

[Harsh Climate]

yes i know. but why would we have a price to pay, unless you just mean that the south would just have to be hit with rain lol.

The price is wede have to put up wi them moaning lmao

[Tom D]

I think a few people have had a little too much to drink and should have a lie down before the 18z comes out!

[Harsh Climate]

Not what rob mackelwee said 3 days of snow m4 northwards.

To be honest I havent made a conclusion of where the snow will be, it could mainly be northern england/central england or least likely southern england. We probably wont know exactly where till the day itself

I think some places could rival the 10 inches shrewsbury got a couple of years ago as the situation will be very similar..

Edited December 26, 2009 by Jed Bickerdike

[johnny1972]

Guys

Missing data or no missing data i find it incredible some of the negativity in some posts. The UK as a whole has had up to yesterday the coldest spell of weather for many years. The charts have been up and down but have trended towards a generally cold to v cold pattern well into the new year. Variations on a day to day basis are inevitable but having read some of GP's posts and some others from the more experienced members on here, one of the things to look for was a combination of the -AO and -NAO set up. The forecast indexes for both remain very negative -2 in the case of the NAO and sub -4 in the case of the AO, well into the new year. Blocking is extensive in the Northern Hemisphere, which many of the LRF's pointed to.

I don't think we have a great deal to worry about re the cold pattern sustaining. Some get very hung up on snow for their area. This is very hard to predict as has been said on here time and time again. I have watched TV footage of some of the snow events on the mainland and parts of N.I. away from were I live and trust me many of you have done really well so far. I only wish the area I lived in saw the amount of snow some have experienced.

Look forward to the remainder of the winter and I for one will take great interest in GP's, SM's NS, BFTP, RJS upcoming posts. These guys seem confident in what they see in the charts so im happy with that !!!!

[keithlucky]

3 days of snow idoubt it more like a metre.

[Snowyowl9]

its people in the sfar south moaning and groaning in particular. they forget the snow would still fall somewhere further north.

Mr HD lives further NW by quite away from here so he`s had more snow to what

I`ve seen as to one or 2 of his posts last week.

Anyway I`m looking to seeing a frost tomorrow night,

there will still be snow waiting for more to come and take it away,and next week a blizzard is still in the making.

http://91.121.93.17/pics/brack2.gif

Goonight all.

[lukemc]

Hi,

Just wondering what would happen if FI to deep FI on the ECM and GFS where to come off somebody posted that on the GFS 12z run the Greenland high fails to link up with the Scandinavian high and this could open the door the the Atlantic coming back in but I can't see why if this happened it would necessarily mean a quick return to zonality can anyone explain as the greenland high would still be in situ anyway can anyone explain? Anyway is their any zonality progged in FI in any of tonights 12z runs? And if we did get a return to zonality I don't necessarily think it will be of the mild variety for example last January was an example of "cold zonality" and we even got some lowland snowfall out of it where I live in Liverpool and could anyone see a January 1984 style scenario occurring that would be interesting!

[yamkin]

i find it very difficult to understand how the met office have come out with the kind of medium term forecast considering models are not in agreement,

The MetO have their private model we do not see, so maybe they have this end of December colder period agreed.

[swilliam]

The De Bilt ECMF ensembles are out.

Still a very strong trend downwards.

[johnny1972]

The price is wede have to put up wi them moaning lmao

Couldn't agree more Jed !!

[Thundery wintry showers]

Let's cut out the bickering and remember that in this kind of setup with northern blocking galore- an extreme rarity at this time of year over the last couple of decades- the models are rarely going to "nail" the correct outcome until 4 days out at most. I saw a post by Steve Murr a while ago saying that the shortwave that, for most of England and Wales, scuppered the February 2001 "very nearly easterly", was picked up at 3 days out (just as well I didn't join the "model watching rollercoaster" until a year and a half later!). Meanwhile, if you remember, the easterly of 17/18 December 2009 was not "nailed" until about 3 days beforehand, with continuous chopping and changing regarding its duration and intensity. In fact most of the runs underdid that easterly somewhat at 4-6 days out, showing the -10C 850hPa line struggling to cover the SE corner when in reality it covered most of eastern England and also SE Scotland.

The key point is that the models will continue to chop and change at this range. We are getting towards the time when prospects towards New Year should be being firmed up, but in reality we probably have a good two days to go before that happens. As often happens, I think a middle ground scenario is likely with some sort of battleground over the Midlands with sleet/snow on its northern flank, then a couple of days of north-easterly and northerly winds, and then, well, it's anyone's guess, but probably not particularly mild away from the south.

[Harsh Climate]

Let's cut out the bickering and remember that in this kind of setup with northern blocking galore- an extreme rarity at this time of year over the last couple of decades- the models are rarely going to "nail" the correct outcome until 4 days out at most. I saw a post by Steve Murr a while ago saying that the shortwave that, for most of England and Wales, scuppered the February 2001 "very nearly easterly", was picked up at 3 days out (just as well I didn't join the "model watching rollercoaster" until a year and a half later!). Meanwhile, if you remember, the easterly of 17/18 December 2009 was not "nailed" until about 3 days beforehand, with continuous chopping and changing regarding its duration and intensity. In fact most of the runs underdid that easterly somewhat at 4-6 days out, showing the -10C 850hPa line struggling to cover the SE corner when in reality it covered most of eastern England and also SE Scotland.

The key point is that the models will continue to chop and change at this range. We are getting towards the time when prospects towards New Year should be being firmed up, but in reality we probably have a good two days to go before that happens. As often happens, I think a middle ground scenario is likely with some sort of battleground over the Midlands with sleet/snow on its northern flank, then a couple of days of north-easterly and northerly winds, and then, well, it's anyone's guess, but probably not particularly mild away from the south.

I agree.

The way this winter is shaping at the moment, we COULD be on the verge of a classic. And if that was going to be the case the models would struggle just like they apparantly did in 1963. In the last week or so weve constantly had hints of much milder/zonal weather occuring, which just isnt happening. Me included have learnt a lesson during this cold spell that when the charts strongly hint at a brakdown or mild, you shouldnt just look into the past and think it will happen again. The difference this year as many have stated we have a strongly negative NAO/AO, the implications of this should herald more of the same

[swilliam]

The De Bilt ECMF ensembles are out.

Still a very strong trend downwards.

In the 'normal' format it can be seen that in FI the OP was very much on the mild side and the control went off on one again (much like the GFS control) - demonstrates the possibilities for this spell though.

So I think we should delay the razor blades for few more days and see what happens.

BTW I do not think the position of the low next week has a massive effect on the prospects for long term cold. It is more to do with the following depression, how much WAA it induces over Iberia/France and whether this links to the block from Greenland via the ridge over Scandinavia (i.e. as shown on the GFS OP). It seems to depend on the orientation of Greenland high. All very plausible but pretty marginal as to whether this occurs or not but has huge effect on the longer term prospects.

Edited December 26, 2009 by swilliam

[Stu_London]

Reading some of the posts on this thread and I do agree with Stu that the models have downgraded the potential of a prolonged cold spell. However I strongly disagree that just because they have downgraded doesn't mean the downgrades will continue. I have to laugh at such statements because have some forgotten what happened prior to our recent cold spell. We had a 24hr period where the models seriously downgraded the cold spell and I remember a particularly poor 12Z run. However as the cold spell came closer the models upgraded especially with regards to the intital E,ly.

You might well be right Dave and you are quite correct that we quite often get a series of small upgrades when a spell gets into the realms of the reliable timeframe.

I'm actually a little more hopeful that after viewing the ECM that the the cold snap wont get squeeezed any further.

[nick sussex]

The ecm ensembles are evident of why the early timeframe and the track of the low will impact greatly later. The ecm operational run is at the top of members for the crucial lows track period. Much later it becomes a mild outlier. For those point scoring regarding the snow please bear this in mind, the further north the low tracks the more likely any snow will be washed away within a few days!

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

[Geordiesnow]

If there was missing data in any of the runs, the models in my eyes have not shown it. The only chart i can find which might back up that possibility is the ecm 168 hour chart which does seem a little strange and unusual.

Anyways, going from the model output, the only place where i can say with a little bit of confidence that probably won't receive snow is the south coast, the cold uppers hardly get to this area even in the better runs but as we know things can change quickly.

UKMO is once again is on it's own regarding positioning of the low, whilst the GFS/ECM further south albeit in slightly different positions. Be interesting what the 18Z says, last night the low was positioned too far north but it did recovered later on in the run so it will certainly be a positive if it trends with the other GFS runs.

[Paul]

Hi all, before the 18z comes out just a reminder that everyone involved in here needs to remember the topic title (ie model discussion) and also remember the forum guidelines which state that you need to respect the other people using the forum.

It's Xmas and the team don't have the time to mess about deleting posts and dealing with people who ought to know how to behave, so anyone causing issues in here with off topic, incendiary or insulting posts will be stopped from posting until the new year without any further warning.

[Cecil Hogmanay Melchett]

The ecm ensembles are evident of why the early timeframe and the track of the low will impact greatly later. The ecm operational run is at the top of members for the crucial lows track period. Much later it becomes a mild outlier. For those point scoring regarding the snow please bear this in mind, the further north the low tracks the more likely any snow will be washed away within a few days!

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

NIck those ecm ensembles are a thing of beauty!!!

A LOT of those members going for a frigid Easterly .

Edited December 26, 2009 by happy days

[East Herts Snow]

I posted this earlier after the 6z run, as it is frustrating to see some of the downbeat posts tonight.

I think nowadays we are spoilt for choice with the amount of weather charts that we can now access on a whim.

I recall the days when I would be constantly refreshing the teletext weather page on TV! Now I can access up to date pressure, dew point, ground temperature, air thickness levels, upper stratosphere charts at will.

However as the atmosphere is so chaotic, charts that are showing events 96 hours out tend to not happen, or the event turns out to be a watered down version (as is possibly happening for next week). We were originally going to receive a couple of blizzard type events across a large area, but this now appears to be a watered down one snow event for a smaller area.

This is not having a pop at the various meteorological organisations and their computer programmed outputs, what they are trying to calculate accurately are probably the most complicated mathmatical/phyics formulas known to man! The more into the future the projections are, the lot less accurate they will be, i.e a volcano erupting in Indonesia can totally change the worlds weather patterns almost instantly.

I tend to now only concentrate on charts up to a maximum of 5 days (apart from snow forecasts which I only look up to 24 hours), anything after 5 days I use as a rough guide only.

Also look out for regular postings from the more senior technical posters (I refer to them as the Old School mob), AKA John Holmes, Glacier Point, Steve Murr, Nick Sussex, Nick F, Kold Weather, The Eye in the Sky, Blast from the Past, Thundery Wintry Showers). They mix their technical skills with good old previous experience. I sometimes find the experience helps more with these cold set-ups than possibly deciphering the many technical charts(although I have learnt so much from the above posters that I can now form my own basic weather forecasts for IMBY).

NB - Apologies if I have left anyone out from my Old School list of posters!

Remember past memorable cold spells tended to appear with very short notice.

Edited December 26, 2009 by North Londoner

[nick sussex]

In terms of the low a northerly track would indicate not enough blocking to the north with the curve of the jet taking the colder air into the Atlantic, the low tracking into France on a more west to east or preferably wnw/ese trajectory would suggest blocking further east to the north this down the line will help sustain the cold and with it more snow chances. For those slating some posters from the south for pointing the importance of a southerly track before doing this bear in mind it's not down to a bias but generally them wanting a colder pattern to last for the WHOLE UK!

I've made numerous posts saying much the same thing all day and am beginning to wonder whether some members understand English!