General Model Output Discussion

[keithlucky]

If you read the post again what evidence Keith is suggesting is the Met O, Micheal Fish forecast.

Some may read the Met O forecast and look at the model output and be somewhat confused. However im not and I can explain exactly why the Met O outlook is more wintry than the models suggest.

Like I say many times in some circumstances you have to look at the model output and figure out whether what they are suggesting is plausible and if not what is the likely outcome. Now the Met O outlook is probably more wintry for two reasons. The first one being the ECM ensembles and secondly the duty forecaster may feel the models are underestimating the block to our NE. This can clearly be seen as the Met O have discounted recent UKMO model output.

With this current pattern its quiet plausible to see a sudden shift in the model output towards a much colder E,ly and this could even occur within +96. This is why im not discounting the possibility just yet. Remember forecasting isn't just quoting what the models say because frankly even my mother could do this! The trick of forecasting is knowing when the models are wrong or right. Our current pattern requires something that is often lacking these days and thats called forecasting instinct. Unfortunately this forecasting instinct is being lost these days as we become more dependable on the models!

Im not saying an E,ly is on its way but im too old and wise to assume mild SW,lys will occur just because the GFS says so.

Thats what i am saying based on experience not computer predictions,as michael fish says hp over russia is huge and building and moving westwards cant beat gut instinct from sombody whos experience counts more than computer model predictions.

[Jack Wales]

If you read the post again what evidence Keith is suggesting is the Met O, Micheal Fish forecast.

Some may read the Met O forecast and look at the model output and be somewhat confused. However im not and I can explain exactly why the Met O outlook is more wintry than the models suggest.

Like I say many times in some circumstances you have to look at the model output and figure out whether what they are suggesting is plausible and if not what is the likely outcome. Now the Met O outlook is probably more wintry for two reasons. The first one being the ECM ensembles and secondly the duty forecaster may feel the models are underestimating the block to our NE. This can clearly be seen as the Met O have discounted recent UKMO model output.

With this current pattern its quiet plausible to see a sudden shift in the model output towards a much colder E,ly and this could even occur within +96. This is why im not discounting the possibility just yet. Remember forecasting isn't just quoting what the models say because frankly even my mother could do this! The trick of forecasting is knowing when the models are wrong or right. Our current pattern requires something that is often lacking these days and thats called forecasting instinct. Unfortunately this forecasting instinct is being lost these days as we become more dependable on the models!

Im not saying an E,ly is on its way but im too old and wise to assume mild SW,lys will occur just because the GFS says so.

TEITS, is this just not a case of dismissing the models because they do not produce what we want to see. I agree with you that human input very beneficial for the short term forecasts but I'm not sure if 'instinct' has ever been used by the meto etc, all forecasts must be underpinned by science regardless of how tentative the understanding of it is.

Edited January 14, 2010 by Jack Wales

[nick sussex]

Tonights freebie ecm info is the postage stamps for all 50 ensemble members upto 168 hrs. A lot of variation in terms of solutions, quite a few show a battle ground scenario, however not many go for a proper easterly at that stage.

http://www.ecmwf.int/samples/d/banner/page.html

It's a difficult call as modelling the boundary between cold and less cold at that timeframe will have a large margin for error, because of the set up a relatively tiny global distance of a hundred to two hundred miles could make a massive difference to the weather on the ground.

The models still can't really agree on the set up of the Atlantic trough and this is a major player and how much energy goes into the southern arm of the jet. The El Nino at present is expected to power up the southern arm of the jet but its really how the energy gets distributed towards western Europe that will make or break a possible colder spell of weather.

For the moment at least we see general model agreement in that a proper easterly is unlikely but a more probable colder surface flow from the se, to get colder upper air westwards I think its going to be whether the Atlantic trough disrupts with a shortwave running se into Europe.

In terms of any possible snow even allowing for what on the face of it doesn't shout snow there are actually several possible chances, for newer members don't worry too much about the 850's, the guidance for will it or won't it snow is a different ball game with continental air masses, you're looking for a flow drawn from mainland Europe, this is drier air with lower dew points and favourably there is a good surface pool of colder air to draw on.

However what is key is that the initial ridge from the east can at least get far enough west to bring some colder surface air into the UK. For the moment this is the main thing to look out for, also the Atlantic trough in terms of its tilt, simply put, north/south okay, running nw/se good, ne/sw bad!

Overall then it's on a knife edge and could go either way. Really hard to call this one so i think i'm sitting on the fence for the timebeing!

[Cecil Hogmanay Melchett]

oh no just read the regional threads are being shut at midnight

sure hope they are brought back before the end of winter i'll miss the regional threads.

Guess that really does mean its all over

ecm looks ok but apparently the ens aren't as good.

[snowingtequila]

TEITS, is this just not a case of dismissing the models because they do not produce what we want to see. I agree with you that human input very beneficial for the short term forecasts but I'm not sure if 'instinct' has ever been used by the meto etc, all forecasts must be underpinned by science regardless of how tentative the understanding of it is.

instinct probably hasn't been used by the metoffice but a reasoned opinion backed up by science probably has. I think only forecasts from the met have to be underpinned with science my forecasts certainly don't.

My father has correctly forecast this winter so far only for 3 to 4 days at a time but very accurately, he knows nothing of science b ut has worked outside all his life.

I think the models are struggling at the moment, maybe because of upstream changes which I do not understand or maybe because we are stuck between two areas in a no man's land which is why the models are changing a lot and will continue to do so.

[TEITS]

TEITS, is this just not a case of dismissing the models because they do not produce what we want to see. I agree with you that human input very beneficial for the short term forecasts but I'm not sure if 'instinct' has ever been used by the meto etc, all forecasts must be underpinned by science regardless of how tentative the understanding of it is.

Im sure forecasting instinct is used all the time at the Met O. I doubt the ECM just base their forecasts on the ECM ensembles and use instinct to see if what is being suggested is plausible.

As for dismissing the models and to be honest like I said earlier my boiler could be with a rest. However you cannot ignore a 1060mb Siberian HP. Fair enough at the moment it looks as though it will be too far E but what im saying is future model output may trend this further W. Assuming the mild runs will come occur and disregarding the colder runs is hardly scientitic either is it!

At the moment im keeping an open mind for next week because I can easily see how this could change more favourably in the model output. If this change does occur then its more likely within +144 and more especially +96. So who knows come Saturday the model output may look very different.

[winterof79]

johncoolj.PUNCTUATION.Good night folks,hopefully fridays out put may shed a little more light on proceedings.Time to let the experts try their hand.i.e Mr Fish etc.

[sundog]

cold weather is going may come back for 2 days if even then its gone west wins the war again wouldent say we will see much in the way of cold in feb

I think it maybe rather foolish to write off the rest of the winter as its only mid Jan. Even if the atlantic takes control for a while there are still many weeks of winter left so anything could happen. I dont think winter is finished with us yet.

[derrylynne]

Thats what i am saying based on experience not computer predictions,as michael fish says hp over russia is huge and building and moving westwards cant beat gut instinct from sombody whos experience counts more than computer model predictions.

Michael Fish has the experience of forecasting back in the days when we used to get winters like this. And I used to look at charts back in them days too. It is quite right to use instinct based on experience as there is no way a high building over Russia can be ignored. They used to have a way of moving west and biting us in the backside in the olden days. And that is what Michael Fish must be seeing. In fact it were not unusual for the charts to change at very short notice either. So there is no way we can write off the cold returning. And I prefer mild so would rather not see that high - and at 1067 that is a hell of a strong one. I have to agree that the models are not used to or programmed for this current type of setups - and that changes at short notice are to be expected. The younger members will have to draw experience from looking back in the archives for the same type of setup or listen to the older members that have experienced these setups....

[Pixel]

Remember forecasting isn't just quoting what the models say because frankly even my mother could do this!

The trick of forecasting is knowing when the models are wrong or right. Our current pattern requires something that is often lacking these days and thats called forecasting instinct. Unfortunately this forecasting instinct is being lost these days as we become more dependable on the models!

"knowing when the models are right or wrong" is why I'm here. Merely cutting and pasting a 'chosen' model graphic and saying "wow" doesn't do it for me - I want opinions based on experience and 'instinct'

TEITS et al - whether your opinions are right or wrong, I appreciate all your un-biased observation and instinct.. and when you and other experienced members get it wrong, who cares except you ! I'm confident that you are learning about the weather as much as anyone else here who puts their neck on the line.

No one really knows for sure and that's why we're all here and watching mother nature do her stuff, cold, stormy, heatwave or fog !

analogy: If playing golf was easy, no-one would play it.

Weather forecasting looks easy but isn't - unless you live in California - where the golf is still a hard game :lol:

Model output discussion - that's what it says on the tin. Sorry mods but I really hate all this 'you're right' - 'you're wrong' banter. Stay away unless there's something intelligent and constructive to say here.

That's my 2 penneth

Edited January 14, 2010 by shadowcat

[cold snap]

Tonights freebie ecm info is the postage stamps for all 50 ensemble members upto 168 hrs. A lot of variation in terms of solutions, quite a few show a battle ground scenario, however not many go for a proper easterly at that stage.

http://www.ecmwf.int...anner/page.html

It's a difficult call as modelling the boundary between cold and less cold at that timeframe will have a large margin for error, because of the set up a relatively tiny global distance of a hundred to two hundred miles could make a massive difference to the weather on the ground.

The models still can't really agree on the set up of the Atlantic trough and this is a major player and how much energy goes into the southern arm of the jet. The El Nino at present is expected to power up the southern arm of the jet but its really how the energy gets distributed towards western Europe that will make or break a possible colder spell of weather.

For the moment at least we see general model agreement in that a proper easterly is unlikely but a more probable colder surface flow from the se, to get colder upper air westwards I think its going to be whether the Atlantic trough disrupts with a shortwave running se into Europe.

In terms of any possible snow even allowing for what on the face of it doesn't shout snow there are actually several possible chances, for newer members don't worry too much about the 850's, the guidance for will it or won't it snow is a different ball game with continental air masses, you're looking for a flow drawn from mainland Europe, this is drier air with lower dew points and favourably there is a good surface pool of colder air to draw on.

However what is key is that the initial ridge from the east can at least get far enough west to bring some colder surface air into the UK. For the moment this is the main thing to look out for, also the Atlantic trough in terms of its tilt, simply put, north/south okay, running nw/se good, ne/sw bad!

Overall then it's on a knife edge and could go either way. Really hard to call this one so i think i'm sitting on the fence for the timebeing!

Will the 18Z get you off the fence Nick?

Coming out at 21.45

Edited January 14, 2010 by cold snap

[igloo]

I think it maybe rather foolish to write off the rest of the winter as its only mid Jan. Even if the atlantic takes control for a while there are still many weeks of winter left so anything could happen. I dont think winter is finished with us yet.

i have to agree with you even though the atlantic does look like winning the battle for next week by todays model outputs these charts can change very quick you would have to expect a spell of mild weather at some stage but giving the jets tendency to drive south this year i dont see why it wont again and feb is often our snowiest month of the year.

[gottolovethisweather]

If the jet doesn't play ball then it doesn't matter whether the Russian High is 1045, 1070 or whatever mb.

Maybe then I could be right in my post yesterday, when I mentioned the following concerning TEITS's 'thing up his sleeve' which I believe he still hasn't revealed.

I think your sign is the split jet being hinted at the charts come Sunday allowing a subesequent easterly to build

Whatever, respect is due to the many experts on here that attempt to unravel nature's most outstanding aspect, the weather.

I have no expertise/knowledge technically or scientifically but I love the discussions, time out as the latest model output is forthcoming.

STORMBOY

[Jack Wales]

Im sure forecasting instinct is used all the time at the Met O. I doubt the ECM just base their forecasts on the ECM ensembles and use instinct to see if what is being suggested is plausible.

As for dismissing the models and to be honest like I said earlier my boiler could be with a rest. However you cannot ignore a 1060mb Siberian HP. Fair enough at the moment it looks as though it will be too far E but what im saying is future model output may trend this further W. Assuming the mild runs will come occur and disregarding the colder runs is hardly scientitic either is it!

At the moment im keeping an open mind for next week because I can easily see how this could change more favourably in the model output. If this change does occur then its more likely within +144 and more especially +96. So who knows come Saturday the model output may look very different. :lol:

Goog balanced post there teits, I agree it is on a knife edge for next week, 1060 mb siberian high against 955mb atlantic low. If we're talking about instincts, I think it will be a near miss with the cold staying just to our east. I believe prospects in the longer term could be better though, the AO is forecast to trend negative again after a brief neutral phase...

AO (CPC)

[Thundery wintry showers]

If the jet doesn't play ball then it doesn't matter whether the Russian High is 1045, 1070 or whatever mb.

A few winters back, we had a similarly feature that wouldn't allow Low pressure systems past the Meridian, but because of persistent low heights to the NW and the PV, the High to the NE could never ridge far enough West to bring an easterly.

Yes, I think it was in January 2006, when the models threw up cold easterlies on a number of occasions, and each time, we either got nothing or a watered down/modified brief easterly because of the strong PV to the NW.

[MP-R]

If the jet doesn't play ball then it doesn't matter whether the Russian High is 1045, 1070 or whatever mb.

A few winters back, we had a similarly feature that wouldn't allow Low pressure systems past the Meridian, but because of persistent low heights to the NW and the PV, the High to the NE could never ridge far enough West to bring an easterly.

Which year are you talking about recently just out of interest? Backing that, here is an example of just that - a slightly different synoptic setup but just shows the sharp pressure gradient between a deep high to the east and the winning Atlantic.

http://www.wetterzentrale.de/archive/ra/2008/Rrea00120080105.gif

Edited January 14, 2010 by Michael Prys-Roberts

[Mac_SE]

Sign off from Joe B's latest blog update:

"BTW get ready, the thaw ends next week and major snows may be back later next week and beyond."

Anyone know what models Accuweather base their forecasts on, because so far he's been spot on this winter?

[Jason T]

Well i think we will know more by sunday and alot by tuesday next week. There is a real battle coming up.

[yamkin]

Sign off from Joe B's latest blog update:

"BTW get ready, the thaw ends next week and major snows may be back later next week and beyond."

Anyone know what models Accuweather base their forecasts on, because so far he's been spot on this winter?

I know they use GFS & GEM. I'm sure they utilise other models too.

[sandstorm2]

If the jet doesn't play ball then it doesn't matter whether the Russian High is 1045, 1070 or whatever mb.

Maybe then I could be right in my post yesterday, when I mentioned the following concerning TEITS's 'thing up his sleeve' which I believe he still hasn't revealed.

I think your sign is the split jet being hinted at the charts come Sunday allowing a subesequent easterly to build

Whatever, respect is due to the many experts on here that attempt to unravel nature's most outstanding aspect, the weather.

I have no expertise/knowledge technically or scientifically but I love the discussions, time out as the latest model output is forthcoming.

STORMBOY

No, TEITS is only going to reveal his secret forecast tool if he is correct about the easterly, he really put his head on the chopping block with that one saying it has never failed him since he was 10.

Anyway back to the models and I am still thinking that the massive HP to the East is going to influence our weather with a fair bit of snow next week.

There is a lot of talk about the models not being programmed to deal with battle ground situations, do they not just swallow an enormous amount of info and spit out a chart regardless of whether the computer has seen this sort of thing before or not.

We have all these models at our disposal produced by powerful computers and we still choose to believe that 'they haven't seen this before'.

SS"

SS2