General Model Output Discussion

[Snowyowl9]

Very cold 00z output again, nobody knows where the high will move in FI, the gfs & ecm have very different ideas but the outlook is remaining cold, probably a minimum of 10 more days and probably longer than that so there would only be a slow thaw at worst, the areas further south and east have a better chance of having wintry showers continuing and the next 4-5 days look very wintry with a spell of rain/sleet and snow pushing south followed by snow showers and severe frosts with heavy, persistent snow in some central and eastern areas between wed-fri. The gfs 00z in FI is classic stuff with the high eventually pushing into scandinavia and a bitter E'ly across all areas with snow flurries, not much of a downgrade there then!

I think it that run comes off,more likely the the 6z IMO there will be no thawing of any lying snow just a little in the sun,but thats a very long cold spell and probably more cloud will come in and temps will just get lower and lower.

We are looking at the longest cold spell since February 1986.

Edited January 4, 2010 by Snowyowl9

[Glacier Point]

Brilliant post GP. I seem to remember last week or so you mentioned the MJO. You said (in so many words) that we now need to see the MJO enter phases 5,6,7. It has entered the 5 phase area. Would you be able to comment on what happens with phase 5 and possibly phases 6 & 7. http://www.cpc.noaa....O/foregfs.shtml

It's in phase 4 !

The GFS ensembles (possibly suspect in light of today's NOAA commentary) suggest it to break phase 5 around mid month. When the MJO shifts to this position, it will signal the tropics and extratropics to begin adding net westerly flow to the general ciculation, sending to the Global Wind Oscillation into phase 5 as well. This is likely to see the block to the north begin to expand and begin a repeat journey across Greenland towards Canada mid January through early February.

Edited January 4, 2010 by Glacier Point

[yamkin]

It's in phase 4 !

The GFS ensembles (possibly suspect in light of today's NOAA commentary) suggest it to break phase 5 around mid month. When the MJO shifts to this position, it will signal the tropics and extratropics to begin adding net westerly flow to the general ciculation, sending to the Global Wind Oscillation into phase 5 as well. This is likely to see the block to the north begin to expand and begin a repeat journey across Greenland towards Canada mid January through early February.

ooopps phase 4 it is. thanks for the clarification GP

[Ian Fergusson]

Hi Matt,

That is an update to the Met Office's own hi-res model

The previous BBC forecasts were based upon earlier runs of the model which, for some reason puzzling a number of us, was showing rain/sleet in the mix - the risk of this seems to be diminishing somewhat perhaps due to NWP models overdoing dew points (as has occured often before)

Kind Regards

SK

Exactly correct, SK. The later NAE run (arriving after us early folk had completed BBC Breakfast / radio forecasts) has a more predominant snow signal for tomorrow morning; a broader areal spread as the feature runs south and retains a more coherent look to it; and a prospect of further bands of snow following later in the evening, especially into southern-central districts (e.g., Oxon, Wilts). Incidentally the latest GM progs and UKMO thinking reduces the heavy snow risk for London/SE end of week - at least, to an extent - and revisits the same potential later in the weekend albeit confidence remain problematic (hence no advisories for now). An anticyclonic dominance takes over later next week, steadily diminishing snow potential but retaining the cold feed obviously, as expected.

Edited January 4, 2010 by Ian Fergusson

[Guest FireStorm]

It's in phase 4 !

The GFS ensembles (possibly suspect in light of today's NOAA commentary) suggest it to break phase 5 around mid month. When the MJO shifts to this position, it will signal the tropics and extratropics to begin adding net westerly flow to the general ciculation, sending to the Global Wind Oscillation into phase 5 as well. This is likely to see the block to the north begin to expand and begin a repeat journey across Greenland towards Canada mid January through early February.

MJO? Phase 4? Phase 5? net westerly flow?

I will probably get abused by the people who know what all that means but could you possibly translate that into simple terms for me? I've seen phases and "MJO" mentioned before and how upper level stratosphere direction means amazing winter or even larger teapot but it may as well be written in chinese and i really want to know what the lingo means

[Just Before Dawn]

Exactly correct, SK. The later NAE run (arriving after us early folk had completed BBC Breakfast / radio forecasts) has a more predominant snow signal for tomorrow morning; a broader areal spread as the feature runs south and retains a more coherent look to it; and a prospect of further bands of snow following later in the evening, especially into southern-central districts (e.g., Oxon, Wilts). Incidentally the latest GM progs and UKMO thinking reduces the heavy snow risk for London/SE end of week - at least, to an extent - and revisits the same potential later in the weekend albeit confidence remain problematic (hence no advisories for now). An anticyclonic dominance takes over later next week, steadily diminishing snow potential but retaining the cold feed obviously, as expected.

Thanks for the explanation Ian, There was quite a bit of confusion about this early today, but you've cleared that up.

[Glacier Point]

MJO? Phase 4? Phase 5? net westerly flow?

I will probably get abused by the people who know what all that means but could you possibly translate that into simple terms for me? I've seen phases and "MJO" mentioned before and how upper level stratosphere direction means amazing winter or even larger teapot but it may as well be written in chinese and i really want to know what the lingo means

Here you go:

http://www.cpc.noaa.gov/products/precip/CWlink/MJO/MJO_1page_factsheet.pdf

http://www.cpc.noaa.gov/products/precip/CWlink/MJO/MJO_summary.pdf

The gist of it is - the MJO marks the position of organised tropical convection. This leads to pwerful downstream anticyclones generating Rossby Waves which influence the amplitude and length of the mid and upper tropospheric flow. As the MJO migrates eastward, it can bring about varying changes to the global weather pattern, not just that of the Pacific and parts of North America, particularly when the extratropical circulation is 'in-sync' with the tropics.

[rich1]

Exactly correct, SK. The later NAE run (arriving after us early folk had completed BBC Breakfast / radio forecasts) has a more predominant snow signal for tomorrow morning; a broader areal spread as the feature runs south and retains a more coherent look to it; and a prospect of further bands of snow following later in the evening, especially into southern-central districts (e.g., Oxon, Wilts). Incidentally the latest GM progs and UKMO thinking reduces the heavy snow risk for London/SE end of week - at least, to an extent - and revisits the same potential later in the weekend albeit confidence remain problematic (hence no advisories for now). An anticyclonic dominance takes over later next week, steadily diminishing snow potential but retaining the cold feed obviously, as expected.

Always helps having these updates, is good having a working professional from the BBC/Met O on the forum keeping us abreast of present events and the evolving and changing set up

as it is, looking at the output available to us, the 06z is a drier run but still very cold and remains so right up to the end of the output. ECM and Met O are snowier

outlook remains biting cold with the threat of snow for many places for the forseeable future

a far cry from recent Januaries [last year excepted, but this one looks to be potentially the coldest january since perhaps the 80's at least]

[Lewis]

Subtle changes yet again on the models, we have a slacker flow for Friday now as the LP is progged a little further to the sourh. This is most noteable on the 06z GFS which barely has a easterly flow at all now and instead gives us a very slack flow indeed with obviously very severe frosts and ice days...

However what is a downgrade for the short term really raises the risk for a big snow event from the SW...Still the 06z GFS comes mighty close to flattening the whole lot, so we want to move away from that trend, thankfully the ECM has moved away from overpowering the jet again...

Sorry, downgrade for who? you in the SE or the U.K on a term, can we at least for the next 2-3 days look at whats happening now rather than going on and on about downgrades, flattening the whole lot this and that, i just cannot be bothered to read it. Especially coming from a forecaster!

Did anyone listen to what John Holmes said earlier?

These models are fantastic, short term, medium-term, and possibly long term, i think it's absolutely stupid, being up and down on every run that comes out, and i'm so surprised that many of the posters on here ( Koldweather, Steve Murr ) etc, say that we should not take the GFS serious all the time with it being a non euro model, and that the ECM is normally the best etc, and gfs is only good for shortwaves etc, it over does the patterns, or blocking etc.... and so on....

Can we just talk about what the models are showing in reliable time frame? because when we get to the end of this reliable time frame.. Guess what, we are in another reliable time frame that covers this weekend.

Thanks,

Needed to get that off my chest.

Lewis

[Optimus Prime]

I agree, the last few weeks has shown just how bad the GFS performs in out of summer situations. Best to take more notice of the ECM and UKMO at the current time period and not even bother going past Saturday at this stage to see whats going to happen next week with any real worthness.

[izi]

Sorry, downgrade for who? you in the SE or the U.K on a term, can we at least for the next 2-3 days look at whats happening now rather than going on and on about downgrades, flattening the whole lot this and that, i just cannot be bothered to read it. Especially coming from a forecaster!

Did anyone listen to what John Holmes said earlier?

These models are fantastic, short term, medium-term, and possibly long term, i think it's absolutely stupid, being up and down on every run that comes out, and i'm so surprised that many of the posters on here ( Koldweather, Steve Murr ) etc, say that we should not take the GFS serious all the time with it being a non euro model, and that the ECM is normally the best etc, and gfs is only good for shortwaves etc, it over does the patterns, or blocking etc.... and so on....

Can we just talk about what the models are showing in reliable time frame? because when we get to the end of this reliable time frame.. Guess what, we are in another reliable time frame that covers this weekend.

Thanks,

Needed to get that off my chest.

Lewis

Sorry for off topic post but I am + 1 for a thread to be made for short term (out to +144 max) and another for trending.

I also am suprised as a complete novice that some of the more experianced chart readers take each one too literally. At least do a 'round up' of thoughts every 24 hours taking several runs in to consideration instead of one.

Edit: turm /= term

Edited January 4, 2010 by izi

[MisfitDog3]

"Did anyone listen to what John Holmes said earlier?"

And we all need to remember that FI is still FI even if the forecast way out 10 days plus is for cold! (Nice model runs though! :-) )

[Lewis]

Sorry for off topic post but I am + 1 for a thread to be made for short turm (out to +144 max) and another for trending.

I also am suprised as a complete novice that some of the more experianced chart readers take each one too literally. At least do a 'round up' of thoughts every 24 hours taking several runs in to consideration instead of one.

Thanks,

I already made a proposal about that to Paul via pm, i also made a thread for it to be deleted right away, a lot of people don't realize that the model is not all about FI and trend spotting, 99% of people are more interested in what the models are showing now and in reliable time frame, because anyone with common sense knows things change so much with models!

If people want to talk trends and bicker about FI, then this is the thread to do it;

In depth and technical model discussion

This thread is for general, a lot of users may not be "experienced" with charts, like me, i'm good with reading charts, but not at patterns or trends, i take every run as it comes. I don't look into FI, i'm more interested about now, and tomorrow not next week. Or in 3 weeks time.

Thats why so many people get confused on here.

Edited January 4, 2010 by Storm Force Lewis

[Essex Boy]

Thanks,

I already made a proposal about that to Paul via pm, i also made a thread for it to be deleted right away, a lot of people don't realize that the model is not all about FI and trend spotting, 99% of people are more interested in what the models are showing now and in reliable time frame, because anyone with common sense knows things change so much with models!

If people want to talk trends and bicker about FI, then this is the thread to do it;

http://forum.netweat...del-discussion/

In depth and technical model discussion

This thread is for general, a lot of users may not be "experienced" with charts, like me, i'm good with reading charts, but not at patterns or trends, i take every run as it comes. I don't look into FI, i'm more interested about now, and tomorrow not next week. Or in 3 weeks time.

Thats why so many people get confused on here.

Yeah for what its worth, I second the splitting up of the model discussion posts into pre and post FI stuff. It takes ages to catch up on threads as it is, let alone then filter down the comments individually by +144 or whatever (and then by geographical region!). Cheers. EB.

[swilliam]

Thanks,

I already made a proposal about that to Paul via pm, i also made a thread for it to be deleted right away, a lot of people don't realize that the model is not all about FI and trend spotting, 99% of people are more interested in what the models are showing now and in reliable time frame, because anyone with common sense knows things change so much with models!

If people want to talk trends and bicker about FI, then this is the thread to do it;

http://forum.netweat...del-discussion/

In depth and technical model discussion

This thread is for general, a lot of users may not be "experienced" with charts, like me, i'm good with reading charts, but not at patterns or trends, i take every run as it comes. I don't look into FI, i'm more interested about now, and tomorrow not next week. Or in 3 weeks time.

Thats why so many people get confused on here.

How do you know that 99% of people are more interested in what the models are showing now - if that was the case 99% of the posts would be about that. What do you define as the reliable timeframe, it could be anything between 24 hrs and +144 hours depending on the setup. Some people might be interested in 1 day, some 3 days, some 5/6 days - do you want a thread for each of these? Also if it is the reliable timeframe then there is nothing to discuss? This thread is currently for everybody to use to discuss the model output and you should respect that. If something does not interest you then do not read it.

[nick sussex]

"Did anyone listen to what John Holmes said earlier?"

And we all need to remember that FI is still FI even if the forecast way out 10 days plus is for cold! (Nice model runs though! :-) )

I think the reason the media have started highlighting the chance that the cold could stay for at least the next 10 days is such a strong signal for the AO and NAO to remain deeply negative, bear in mind also that any upstream changes would take time to feed down into western europe, often we see zonal spells that look locked in, in this instance the cold seems locked in, what we probably will see though is that the snow risk will reduce next week for areas way from the se as high pressure sits just to the north, also we will lose those very cold upper air temps but will still be pulling in a cold surface flow from the continent. There is a chance that lows may try and edge in from the sw but how far north they get is of course uncertain.

In terms of the more immediate term we're looking at that band of snow heading se and a further area of snow tied in with an occlusion over nw and northern England. There is still some uncertainty regarding that slack area of low pressure to the east and how long that takes to clear or will it form another shallow feature. We have good model agreement on the general pattern but there are often local surprises in these situations.

[Lewis]

How do you know that 99% of people are more interested in what the models are showing now - if that was the case 99% of the posts would be about that. What do you define as the reliable timeframe, it could be anything between 24 hrs and +144 hours depending on the setup. Some people might be interested in 1 day, some 3 days, some 5/6 days - do you want a thread for each of these? Also if it is the reliable timeframe then there is nothing to discuss? This thread is currently for everybody to use to discuss the model output and you should respect that. If something does not interest you then do not read it.

If you closely looked, it's the same regular posters in here, Kold weather, TEITS, Steve Murr, Nick F (which don't get me wrong, know what they are talking about) but it's the rest of us that have to pick up the scraps and scratch our head to what they are talking about, because 9 times out of 10 they are always talking about FI and trends, and if anything is in short-term/reliable time frame, they only mention "IMBY".

Short term/ realible time frame too me is 0-72 hours generally, but out to 120 hours would be fine.

And to the moderators, i'm terribly sorry for going off topic, and i really hope i don't make work much harder for you, because i appreciate your busy enough.

Lewis

Edited January 4, 2010 by Storm Force Lewis

[Harsh Climate]

Sorry, downgrade for who? you in the SE or the U.K on a term, can we at least for the next 2-3 days look at whats happening now rather than going on and on about downgrades, flattening the whole lot this and that, i just cannot be bothered to read it. Especially coming from a forecaster!

Did anyone listen to what John Holmes said earlier?

These models are fantastic, short term, medium-term, and possibly long term, i think it's absolutely stupid, being up and down on every run that comes out, and i'm so surprised that many of the posters on here ( Koldweather, Steve Murr ) etc, say that we should not take the GFS serious all the time with it being a non euro model, and that the ECM is normally the best etc, and gfs is only good for shortwaves etc, it over does the patterns, or blocking etc.... and so on....

Can we just talk about what the models are showing in reliable time frame? because when we get to the end of this reliable time frame.. Guess what, we are in another reliable time frame that covers this weekend.

Thanks,

Needed to get that off my chest.

Lewis

I agree with that.

The way this cold spell has developed/is happening so far, anything past 96h is pure speculation! weve had a few times now where in the SO CALLED reliable output period has looked nailed on for it to backtrack dramatically nearer to the time (possible breakdowns/severity of snowfalls/suprise snowfalls.)

You just cant come to whole new conclusions each day from looking at a few model outputs, in this situation you have to look at all the different variables (Nao/AO forecasts, gfs/ecm/ukmo etc/ european snow cover etc) as these will all have large impacts on our upcoming weather.. and all of these together shouldnt change too dramatically in the 96h timeframe...

Im only just looking into FI with a glancing eye at the moment as all the signals are good, it doesnt matter exactly what the models are saying med/long range as the main things are expected to be in place, BLOCKING OVER UK or to the WEST, A VERY COLD CONTINENT, NEGATIVE AO/NAO forecast.... Just enjoy the snow prospects over the next few days as nobody knows exactly whats guna happen after the weekend

my guess would be high pressure over the uk, slightly less cold with perhaps a light SE/E feed.

Edited January 4, 2010 by Jed Bickerdike

[izi]

How do you know that 99% of people are more interested in what the models are showing now - if that was the case 99% of the posts would be about that. What do you define as the reliable timeframe, it could be anything between 24 hrs and +144 hours depending on the setup. Some people might be interested in 1 day, some 3 days, some 5/6 days - do you want a thread for each of these? Also if it is the reliable timeframe then there is nothing to discuss? This thread is currently for everybody to use to discuss the model output and you should respect that. If something does not interest you then do not read it.

I’d argue that both the future and the now are equally as important, but the future is far less easy to predict. This is why people get annoyed every run when there are many posts ramping or saying 'ah no that run was bad' etc when really they want to look at specifics over the next few days.

Generally speaking, ensembles tend to agree to around +100hrs, and break down after that.

Edited January 4, 2010 by izi

[swilliam]

If you closely looked, it's the same regular posters in here, Kold weather, TEITS, Steve Murr, Nick F (which don't get me wrong, know what they are talking about) but it's the rest of us that have to pick up the scraps and scratch our head to what they are talking about, because 9 times out of 10 they are always talking about FI and trends, and if anything is in short-term/reliable time frame, they only mention "IMBY".

Short term/ realible time frame too me is 0-72 hours generally, but out to 120 hours would be fine.

And to the moderators, i'm terribly sorry for going off topic, and i really hope i don't make work much harder for you, because i appreciate your busy enough.

Lewis

I believe that 0-72 hrs is pretty well covered by either regional threads or will it won't it snow type threads - perhaps the mods could give you some guidance there.#

And one other thing - people are interested short term with the current set-up - if we had 5 days of mild dry SW winds or anticyclonic gloom progged then you and a lot of others would want to be talking about upstream development.

The usual people as you suggest are discussing this most of the time - then when some cold weather comes into the semi reliable time frame this thread becomes clogged up with the will it won't it snow brigade.

Edited January 4, 2010 by swilliam

[Lewis]

I believe that 0-72 hrs is pretty well covered by either regional threads or will it won't it snow type threads - perhaps the mods could give you some guidance there.

Yes i agree to some affect, but you can't have long range without short range, a lot of people are not specifically experienced or interested in the models in regional threads, they are more interested in guidance and information (other members forecasts etc, and reading John Holmes verdicts on things "including his LRF'S which i must say are spot on").

It's down to the moderators and Paul,

I can only say so much, and if a lot of members don't agree with me then it's no skin off my back, all i want to have is a place were we can discuss reliable time frame, and enjoy it. And not having to go through 3 pages of posts just to find something discussed on the short term models.

Lewis

Edited January 4, 2010 by Storm Force Lewis

[nick sussex]

Yes i agree to some affect, but you can't have long range without short range, a lot of people are not specifically experienced or interested in the models in regional threads, they are more interested in guidance and information (other members forecasts etc, and reading John Holmes verdicts on things "including his LRF'S which i must say are spot on").

It's down to the moderators and Paul,

I can only say so much, and if a lot of members don't agree with me then it's no skin off my back, all i want to have is a place were we can discuss reliable time frame, and enjoy it. And not having to go through 3 pages of posts just to find something discussed on the short term models.

Lewis

Hi Lewis i do understand where you're coming from as some of the regional threads have turned into an emotional rollercoaster and hard to find what you're looking for. I think it would be fair to have a general model discussion like this thread for all output zero to FI and a separate thread for just upto 72hrs but that would have to be well moderated.

I think however it's a little unfair to criticize the regular posters as we are just discussing the models, there are no restrictions in this thread apart from being on topic. I would say though that any new model thread must just stick to upto 72hrs otherwise it wouldn't work.

[swilliam]

Yes i agree to some affect, but you can't have long range without short range, a lot of people are not specifically experienced or interested in the models in regional threads, they are more interested in guidance and information (other members forecasts etc, and reading John Holmes verdicts on things "including his LRF'S which i must say are spot on").

It's down to the moderators and Paul,

I can only say so much, and if a lot of members don't agree with me then it's no skin off my back, all i want to have is a place were we can discuss reliable time frame, and enjoy it. And not having to go through 3 pages of posts just to find something discussed on the short term models.

Lewis

I think if a major or interesting event such as might have happened Fri/Sat comes up to the reliable time frame then there will be a lot of discussion about the short/medium term models. There were two cases recently. The first was the easterly before Xmas with the track, position and alignment of the SW that came down the North Sea and introduced the Easterly being endlessly discussed. Similarly we had the case recently when we had the infamous low that introduced the current cold spell. There was much detailed discussion about the movement of the low and the prognosis from the different models. In fact there was even discussion afterwards about which models called it correctly. If the possible SE event becomes more likley again there will be plenty of discussion (and not because it is in the SE!) as there will be when we finally get the Atlantic trying to break the cold spell - which appears to be likely in a couple of weeks time.

PS I concur with NS above - the regional threads are almost impossible to read except for reporting of snow events.

Edited January 4, 2010 by swilliam

[Serendipity]

I don't really get what all the bickering is about other than there seems to be a real lack of tolerance between the experienced posters and not so experienced and of course between the different regions.

I said last night and I still stand by it, that what is helpful is when people quantify their statements so stating "This is a downgrade" needs further info - a downgrade for everyone? your area? comparing differing charts or like for like charts? (ie 12z v 6z or 12z v yesterdays 12z etc).

In the reliable timeframes I see plenty of snow potential at the moment for many areas though! For me in the Midlands I would say the last 24 hrs have been a bit of an upgrade but appreciate, for example, that some in the SE may interprete it completely differently. I thought the fax charts were quite inspiring.

I don't know whether the thread needs more splitting up but do feel perhaps those who get irritated by mundane basic posts (like mine I suspect) may be better off sticking to the techincal thread - a thread I for one would never consider myself qualified to post in!

On another note, I still cannot figure out how to link to charts to back up my thoughts and imagine I will find my posts disappearing if I cannot substantiate my thoughts so if anybody can PM and exaplin it to me in VERY SIMPLE TERMS then thank you!

[stewfox]

It's down to the moderators and Paul,

I can only say so much, and if a lot of members don't agree with me then it's no skin off my back, all i want to have is a place were we can discuss reliable time frame, and enjoy it. And not having to go through 3 pages of posts just to find something discussed on the short term models.

Lewis

I don't think it's off topic but that's for the mods to decide

I wonder if its 'harder' for people to talk about things going on within T96, troughs, lows etc

I can't remember the last time we had a Fax chart or Map with some of those nice pen swiggles showing directions of projected lows within T96 etc

It clearly 'exciting times' and posting T168 or T244 charts with -20c over London its 'fun' but ……

I appreciate when /what if it will snow in an area is all now casting

Nice to see some pen swiggles on T24 Fax charts

Edited January 4, 2010 by stewfox