Model Output Discussion

[Paul]

Folks, can we lose the playground mentality please? Just gone through and deleted a number of posts with name calling and hissy fits within them which clearly have no place in here..

[BLAST FROM THE PAST]

Not an over fixation at all - it is just that the overall background of factors are not as conduisive as they were for a return to the conditions we have previously seen. It is in that sense that any potential MMW is important to offest those factors. Remember it was the upwelling phases in the lower stratosphere that played a major part in ushering us into the very cold weather of recently - that is now over and we have a backlog of positive zonal winds to deal with. This is going to make it harder for blocking to back the cold south and west enough once again to us

MMW IMO is not needed. The models are picking up nicely now the signal of stormy weather 25-31 pinpointed for a long time now and this has a chance for developing a very cold flow behind it as the LPs get east of the UK and a ridge builds behind.

BFTP

[TEITS]

MMW IMO is not needed. The models are picking up nicely now the signal of stormy weather 25-31 pinpointed for a long time now and this has a chance for developing a very cold flow behind it as the LPs get east of the UK and a ridge builds behind.

BFTP

Moring Fred.

Have to say mate im not convinced of this stormy period. The SLP ensembles for Dublin suggest a mean around 1010mb for this period with the Aberdeen SLP mean at 1005mb.

http://charts.netweather.tv/ensimages/ens.20100117/06/prmslDublin.png

Whilst there is plenty of scatter the mean doesn't suggest a deep LP system bringing a stormy period.

[Cecil Hogmanay Melchett]

Moring Fred.

Have to say mate im not convinced of this stormy period. The SLP ensembles for Dublin suggest a mean around 1010mb for this period with the Aberdeen SLP mean at 1005mb.

http://charts.netweather.tv/ensimages/ens.20100117/06/prmslDublin.png

Whilst there is plenty of scatter the mean doesn't suggest a deep LP system bringing a stormy period.

interesting pressure ensemble there teits.If anything the trend looks for higher pressure to build over the BI to my eyes.

[TEITS]

interesting pressure ensemble there teits.If anything the trend looks for higher pressure to build over the BI to my eyes.

The period between 25th Jan - 1st Feb is going to be very interesting to watch on the models.

Nearly everyone including the Met O are suggesting near normal temps and unsettled conditions during this period. However I see the complete reverse with a cold spell developing around this timeframe. Already we're seeing the GFS back away from the endless SW,lys like I suggested so it will be interesting to see how this pans out.

The combination of the Siberian HP, increasing heights in the Arctic, LP systems remaining W of Iceland, developing HP system to our N/NE will be the reasons for the next cold spell.

[weather eater]

I will add though thats what the point of going back 3 days to the chart archives. When it comes to model output its what they are showing today thats important.

Actually that's an interesting post, you see I think its very important to look at recent output and not just today's. If you don't take recent output into consideration how can you spot a trend on the operationals and how often have we seen the models pick up a thread, drop it for a day and then go back to it. Part of the problem on the NW model thread is the fact that far to many members take each run as the literal truth, superseding all previous runs on all models. Given that after a couple of days the models are getting beyond the remit of their input data, then yesterdays guesses at the synoptic pattern for lets say Friday, are most likely as good as today's.

Personally I don't have a problem with your posts or your take on the models, however I do recall you saying in the autumn, that you were looking to be more objective this year and you were going to stop chasing easterlies. Whether you feel that is indeed what you have done, is your call.

[PB22]

Mildest set of London ensembles from the ECM that I have seen lately with some runs making the 10C mark:

http://www.meteogroup.co.uk/uk/home/weather/services/ensemble_forecast.html

Of course, mean temperatures mostly close to normal after the next few days, but that is a lot milder than recently.

[Rollo]

Well all i can say is what a mess with the models trying to pull some plausible synoptics out of conflicting teleconnections.The things that stand out though are the block to the east unlikely to sink as this will be held north as the AO goes into negative territory, the formation of cut off lows in the Atlantic and the suggestion that the main Atlantic trough wll be stuck to the west, depending on how far negative the AO goes theres a decent chance that enough disruption will occur to the trough to see shortwaves heading se towards the UK with a build of pressure to the NE.

The Azores high is likely to displace further westwards and may yet again as before Xmas aid the development of further cold weather.I think however we need to get away from trying to find another cold spell as good as the last one, these things are rare but we should be pleased that at least the outlook isn't a typical reset to mild mush that has so often occured in past recent winters.

I think Nicks post descibes the current(standoff)position perfectly,we have already had a cold spell to remember for a long time and this respite will be welcomed by the majority of people. As to the future as a lot of posters have said nothing really seems to be going to happen for a few days and then the weather will do as ever what it wants. IMO if it were to become mild and stay thay way with WIB.s possible Bartlett taking over sobeit,but I personallky think there is quite a but more cold to come,to be realistic to expect a repeat of the last spell is only in our wildest dreams,my bet is for 3 to 4 day northerlies and the end of the month with a couple of further spells of cold throughout Feb and one more come early March.

[weather eater]

Moring Fred.

Have to say mate im not convinced of this stormy period. The SLP ensembles for Dublin suggest a mean around 1010mb for this period with the Aberdeen SLP mean at 1005mb.

http://charts.netweather.tv/ensimages/ens.20100117/06/prmslDublin.png

Whilst there is plenty of scatter the mean doesn't suggest a deep LP system bringing a stormy period.

He may feel that, because the Lunar Module is in full pedigree chum, or maybe that a couple of recent runs have hinted at a deep depression for around that time, certainly the ECM does.

Edited January 17, 2010 by weather eater

[The PIT]

Well if the country file is right I'll owe TEITS 10 virtual pints. Still going for a major snow event Wednesday. Tuesday we have +4 air over the UK by Wednesday evening -4 air over the country which suggests more of a case of the rain turning to snow than starting as snow.

Going to be interesting to watch and everything hangs on actually drawing in colder air.

[Cecil Hogmanay Melchett]

Mildest set of London ensembles from the ECM that I have seen lately with some runs making the 10C mark:

http://www.meteogroup.co.uk/uk/home/weather/services/ensemble_forecast.html

Of course, mean temperatures mostly close to normal after the next few days, but that is a lot milder than recently.

whats interesting on those ens is you can clearly see the further west in europe you are the less cold you will be.the trend on the berlin ens for example shows the siberian losing its grip there and they are well east of the uk. No chance we are getting an easterly,time to look N orth west again.

[NL]

He may feel that, because the Lunar Module is in full pedigree chum, or maybe that a couple of recent runs have hinted at a deep depression for around that time, certainly the ECM does.

You mean perigee...

http://en.wikipedia.org/wiki/Apsis

Oh forget that WE, ha ha i see ya joke..!!

Edited January 17, 2010 by NL

[nick sussex]

Actually that's an interesting post, you see I think its very important to look at recent output and not just today's. If you don't take recent output into consideration how can you spot a trend on the operationals and how often have we seen the models pick up a thread, drop it for a day and then go back to it. Part of the problem on the NW model thread is the fact that far to many members take each run as the literal truth, superseding all previous runs on all models. Given that after a couple of days the models are getting beyond the remit of their input data, then yesterdays guesses at the synoptic pattern for lets say Friday, are most likely as good as today's.

Personally I don't have a problem with your posts or your take on the models, however I do recall you saying in the autumn, that you were looking to be more objective this year and you were going to stop chasing easterlies. Whether you feel that is indeed what you have done, is your call.

I think it really depends on the type of pattern shown, of course looking at the last few days it becomes apparent that the models were too quick to shunt the block se'wards, the trend at the moment is to keep this further north, whilst its unlikely that this can effect the UK directly it does open up other avenues to cold. In terms of Dave chasing easterlies, well thats what fires his main interest in winter months, we all have patterns that we'd like to see during the winter or summer so looking at how they could develop IMO is perfectly fine.

[TEITS]

Personally I don't have a problem with your posts or your take on the models, however I do recall you saying in the autumn, that you were looking to be more objective this year and you were going to stop chasing easterlies. Whether you feel that is indeed what you have done, is your call.

Yep so far I feel i've been pretty objective. The only time i've suggested E,lys is back on Nov 27th for mid Dec and just after Xmas for early Jan. Obviously next week isn't going to be as I expected which is why im investing in a machine gun so I can shoot those Seagulls.

What some have to realise is I view the models differently to some people. I don't take what they say literally beyond +144. My enjoyment is trying to figure out if they are wrong and if so what is the likely pattern. The GFS back in late Nov accurately predicted the mid Dec cold spell. So why did I believe the GFS at +384 when it so often suggests cold E/N,lys. Well the answer is like I say many times, using the models is always about forecasting instinct. The mid Dec cold spell looked synoptically plausible to me which is why I said mid Dec could see a very cold spell develop. At the time I was accused of ramping and misleading members!!

Edited January 17, 2010 by THE EYE IN THE SKY

[cooling climate]

Interesting that the 06z GFS operational run is almost a mild outier for the 20-21st time period.

I should say at least on the London ensembles.

Edited January 17, 2010 by cooling climate

[nick sussex]

Interesting that the 06z GFS operational run is almost a mild outier for the 20-21st time period.

Yes even at this short range theres still uncertainty as to how much cold continental air will get pulled up from the se before the fronts arrive and this is probably causing the UKMO quite a few problems with their forecasts. Normally in this situation though at that range its best to follow the operational runs as their higher resolution should prove more accurate, but I suppose theres a small chance that we might see a little upgrade to the cold upper air profiles.

Edited January 17, 2010 by nick sussex

[Yozzer]

Is it just me or does this chart remind you of something??? Maybe I should post this in a thread for sad blokes of a certain age....sorry ladies!

[weather eater]

I think it really depends on the type of pattern shown, of course looking at the last few days it becomes apparent that the models were too quick to shunt the block se'wards, the trend at the moment is to keep this further north, whilst its unlikely that this can effect the UK directly it does open up other avenues to cold. In terms of Dave chasing easterlies, well thats what fires his main interest in winter months, we all have patterns that we'd like to see during the winter or summer so looking at how they could develop IMO is perfectly fine.

I agree Nick, as I say I don't have a problem with it, Dave always takes the time to explain why he thinks as he does and that's cool, Easterlies float my boat as well, coming from east Anglia helps even though I now live in the High Peak area. My point was that Dave himself thought that maybe he was getting over obsessed, as I say that's his call.

As for the models, I think its always wise to keep in mind model runs over the last few days. I favour the ECM as you know, but I also take in the GFS, UKMO, GEM and sometimes the others as well, the bulk of the time its pretty easy to spot the general pattern out to the 120/144hrs mark. The size of the UK is obviously an issue; the general pattern may well remain the same, yet details can be difficult to call for the UK because of its size.

In terms of a possible easterly from the up and coming pattern, only on a couple of runs a few days ago did any meaningfull easterly show. Usually if a trend has any real credence it will show its hand a few times, even if it goes off the radar, only to come back a couple of days later. On this occasion that really hasn't happened, and consequently the pattern has looked pretty clear for some days now IMO.

[Thundery wintry showers]

I think Nicks post descibes the current(standoff)position perfectly,we have already had a cold spell to remember for a long time and this respite will be welcomed by the majority of people. As to the future as a lot of posters have said nothing really seems to be going to happen for a few days and then the weather will do as ever what it wants. IMO if it were to become mild and stay thay way with WIB.s possible Bartlett taking over sobeit,but I personallky think there is quite a but more cold to come,to be realistic to expect a repeat of the last spell is only in our wildest dreams,my bet is for 3 to 4 day northerlies and the end of the month with a couple of further spells of cold throughout Feb and one more come early March.

From my experiences with people around UEA I'm not sure that the majority of people welcomed the change last week relative to the week before, opinion was strongly divided. Of course the media called last week a 'respite' but the media's perception of public opinion and actual public opinion often don't match. However, this may have had more to do with the dampness, drizzle and absence of sunshine rather than the thaw, and correspondingly I expect the transition to this coming week's weather to be welcomed by most as it will have a more ordinary mix of weather as well as having no snow/ice around at low levels.

I'm still not convinced by Wednesday's snow event even though I think the GFS may be underdoing the input of cold air from the east. My guess is still for a snow event on high ground with rain at low levels, and perhaps sleet or wet snow briefly for some. Sunshine amounts will be higher than I had originally suspected because unlike in January 1996 when the continental block kept the "cleaner" polar maritime out to the west, on this occasion the polar maritime air will make it across in between systems promising much brighter weather.

[weather eater]

Yep so far I feel i've been pretty objective. The only time i've suggested E,lys is back on Nov 27th for mid Dec and just after Xmas for early Jan. Obviously next week isn't going to be as I expected which is why im investing in a machine gun so I can shoot those Seagulls.

What some have to realise is I view the models differently to some people. I don't take what they say literally beyond +144. My enjoyment is trying to figure out if they are wrong and if so what is the likely pattern. The GFS back in late Nov accurately predicted the mid Dec cold spell. So why did I believe the GFS at +384 when it so often suggests cold E/N,lys. Well the answer is like I say many times, using the models is always about forecasting instinct. The mid Dec cold spell looked synoptically plausible to me which is why I said mid Dec could see a very cold spell develop. At the time I was accused of ramping and misleading members!!

Hi Dave, it maybe the seagulls thing is not that far off, but it might just be indicating cold on the continent/Scandinavia rather than impending cold for the UK, even in a full blown easterly our climate is likely to be more benevolent than that of the Scandinavia Baltic regions.

[nick sussex]

I agree Nick, as I say I don't have a problem with it, Dave always takes the time to explain why he thinks as he does and that's cool, Easterlies float my boat as well, coming from east Anglia helps even though I now live in the High Peak area. My point was that Dave himself thought that maybe he was getting over obsessed, as I say that's his call.

As for the models, I think its always wise to keep in mind model runs over the last few days. I favour the ECM as you know, but I also take in the GFS, UKMO, GEM and sometimes the others as well, the bulk of the time its pretty easy to spot the general pattern out to the 120/144hrs mark. The size of the UK is obviously an issue; the general pattern may well remain the same, yet details can be difficult to call for the UK because of its size.

In terms of a possible easterly from the up and coming pattern, only on a couple of runs a few days ago did any meaningfull easterly show. Usually if a trend has any real credence it will show its hand a few times, even if it goes off the radar, only to come back a couple of days later. On this occasion that really hasn't happened, and consequently the pattern has looked pretty clear for some days now IMO.

Yes by and large the easterly was a gfs invention for a few runs, once that cut off low didn't head ese but became slow moving and then absorbed into the main Atlantic trough it wasn't going to happen so i think it was really always going to be trying to get as much surface cold into the UK before the fronts arrived. In terms of the pattern it does look pretty constant now across all the models with the Atlantic just throwing too much energy eastwards to allow the Siberian block to directly effect the UK. However the models have backed away from sinking this too far, in these situations you either want the block to be pushed further nw or just blown out of the way so as not to cause a mild stalemate. At the moment the main driver the trough looks to be banging its head against a brick wall with the block, reluctant to go, because of the margin for error at this timeframe I wouldn't rule out the chance of some more colder continental air occasionally effecting the far se as the models do show some trough disruption. It's really quite strange really the amount of times we see a very strong block appear at the same time as the Atlantic desperate to get in also.

In terms of the extended outlook its hard to decide what will happen because there are quite a few conflicting teleconnections, so i think we've reached an interesting stage in proceedings, i do think though that people have to lower their expectations and not expect a repeat performance of the last month,IMO if the rest of the winter throws up a few cold snaps and some more snow then that would be perfectly acceptable and would still make it a very good winter. I was looking through the archive charts last night and went right through the whole winter of 88/89, it was simply awful apart from a cold snap in early December, i think whenever people feel too despondent about recent winters they should take a look at that, hopefully I will never see a winter like that ever again!

[Thundery wintry showers]

Also remember that the ECMWF operationals went for that easterly for a while before the GFS picked up on it- though this does reflect more badly upon the GFS as it took until a closer timeframe than with the ECM for it to back away.

During the winter of 1988/89 there were also a few marginal snow events kicking around in the second half of February, most notably the 23rd-26th, but apart from a brief easterly shot in northern areas on the 2nd December, that was pretty much our lot for the entire of that winter quarter. January 1989 in particular was remarkable for its absence of snow- it was even more snowless than February 1998 which at least had a snowby beginning and end for some.

Yes, people do have to lower their expectations. Over the UK as a whole the latest cold spell was the severest in terms of length, snowfall and severity since the 1980s- possibly the most so since 1981/82, so we really are talking something exceptional. If we do get another cold spell towards the end of January (which is quite possible, as we're seeing signs of that Siberian block potentially merging with rising pressure to the NW) we'll have to accept that it will probably be more marginal and with snow only for some.

[phil nw.]

Mildest set of London ensembles from the ECM that I have seen lately with some runs making the 10C mark:

http://www.meteogrou...e_forecast.html

Of course, mean temperatures mostly close to normal after the next few days, but that is a lot milder than recently.

Certainly no hint of another cold spell there Paul.

I think the Siberian High is flattering to deceive.

It looks impressive but apart from a brief period of surface cold midweek it`s not going to bring another Easterly this time.

A modified Atlantic has now taken over for the next 7-10 days.

http://www.wetterzen...s/Rtavn1381.png

http://www.wetterzen...cs/Recm1441.gif

http://www.wetterzen...cs/Rukm1441.gif

The models have never suggested Mild South Westerly`s for this forward period although this has been stated in some previous posts.

Based on the 00z`s and 006zGFS however temps. are now and will continue close to average for the foreseeable with quite a number wet and windy days to come.

Edited January 17, 2010 by phil n.warks.

[Frosty.]

The period between 25th Jan - 1st Feb is going to be very interesting to watch on the models.

Nearly everyone including the Met O are suggesting near normal temps and unsettled conditions during this period. However I see the complete reverse with a cold spell developing around this timeframe. Already we're seeing the GFS back away from the endless SW,lys like I suggested so it will be interesting to see how this pans out.

The combination of the Siberian HP, increasing heights in the Arctic, LP systems remaining W of Iceland, developing HP system to our N/NE will be the reasons for the next cold spell.

The latest meto update is pretty ordinary, the type of spell we would see in march rather than January, hardly inspiring.

I'm just waiting for a flock of seagulls.

[bluearmy]

The latest meto update is pretty ordinary, the type of spell we would see in march rather than January, hardly inspiring.

I'm just waiting for a flock of seagulls.

not another eighties band reforming !!!!!

not shocked by the meto update - did you see the ecm ensembles for london ?