Winter Model Discussion 18Z 5/2/13 onwards.

[AmershamMike]

I believe it's the only model where all of its data is freely available.

....thanks for the clarification. Another quick question; how do the models get developed and improved? I imagine any modifications to the underlying algorithms must happen very slowly...

[Panayiotis]

Why does the netweather site use the Gfs output for its forecasts if it is so pony??!

Becuase it comes out 4 times a day, so one could say that its more accurate and reliable in the shorter term.

[Don]

Yeah it is,but what's the use of useless data?

It hasn't always been useless though.

Edited February 5, 2013 by Don

[peterf]

It hasn't always been useless though.

I agree,just seems of late it is way out at times even at close range regards wind speed and precip.

[A.J]

The above points would be better off asked in the correct thread..... http://forum.netweather.tv/forum/67-help-support-and-feedback/

This thread is for Model Output Discussion, and nothing but Model Output Discussion....ta!

[bryan629]

I believe it's the only model where all of its data is freely available.

good answer DJ... I thought it went a bit `iffy` whilst Shannon entropy was in full flow last month, since then its never really recovered handling pattern changes, im defo with steve m on this one , ignore it.

reliable of sorts only to around t+72 hrs anything after just cant be trusted compared to othr models, even lessre reliable ones at the moment.

[davehsug]

So GFS is rubbish in the short term & completely wrong, but it's quite okay to put up charts from t300+ because they show a GH. You ave to laarf!

[SE Blizzards]

Can anyone tell me how the BOM model was looking tonight? I seem to be having a few problems with my computer at present and cant get on to the meteociel site Maybe the same gremlins that seem to be in the GFS model have made their way onto my computer.

[cornish snow]

Sick of them here in kent...... Boooo..... Bad winter here so far regards snow......

Try living here then. These slider lows are a total waste of time down here. Just rain rain rain rain!

[Sawel]

So GFS is rubbish in the short term & completely wrong, but it's quite okay to put up charts from t300+ because they show a GH. You ave to laarf!

Well, it is the model discussion thread, so yes, it is quite ok to post charts at +300 hrs.

[bryan629]

So GFS is rubbish in the short term & completely wrong, but it's quite okay to put up charts from t300+ because they show a GH. You ave to laarf!

yep, and on the next gfs run greenlands going to disappear

[A.J]

With all due respect the replies related to the questionable output of the GFS model and it's strange outputs of late.

Peter, I was actually referring to the question posed...."Why does the netweather site use the Gfs output for its forecasts if it is so pony??!"

again, not a question for this thread, rather for the 'help,support & feedback' thread....

and with that....back to the model output discussion

[pages]

Can anyone tell me how the BOM model was looking tonight? I seem to be having a few problems with my computer at present and cant get on to the meteociel site Maybe the same gremlins that seem to be in the GFS model have made their way onto my computer.

Bom with ECM upto t168 so snow for you then it can't quite manage to force the next low under seems to just sit in the Atlantic so cold mixed out but not mild. At t240 heights are building over Greenland , scandie high still there and said low looks like its heading under and send the cold back our way.

[peterf]

Peter, I was actually referring to the question posed...."Why does the netweather site use the Gfs output for its forecasts if it is so pony??!"

again, not a question for this thread, rather for the 'help,support & feedback' thread....

and with that....back to the model output discussion

No probs

[TEITS]

Im a little concerned after viewing the 18Z GEFS ensembles.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=306&ext=1&y=141&run=18&ville=Londres&runpara=0

We have had alot of scatter around the 9th as I highlighted earlier today but the 18Z ensembles show relatively good agreement for the GFS Op.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=306&ext=1&y=141&run=18&ville=Londres&runpara=0

Whilst I hope the UKMO/ECM continue with the same trend these ensembles have placed a seed of doubt in my mind. Lets hope this is just the GFS/GEFS being useless once again.

[SE Blizzards]

Bom with ECM upto t168 so snow for you then it can't quite manage to force the next low under seems to just sit in the Atlantic so cold mixed out but not mild. At t240 heights are building over Greenland , scandie high still there and said low looks like its heading under and send the cold back our way.

Thanks

[Tamara]

Can anyone tell me how the BOM model was looking tonight? I seem to be having a few problems with my computer at present and cant get on to the meteociel site Maybe the same gremlins that seem to be in the GFS model have made their way onto my computer.

Well here is a snapshot for the period Sunday into Monday where the low slides down across to the SW. It looks good at this time and far enough west hopefully for many

http://modeles.meteo...om-0-138.png?12

Edited February 5, 2013 by Tamara Road

[davehsug]

Well, it is the model discussion thread, so yes, it is quite ok to post charts at +300 hrs.

Of course Sawel, but it's the same people rubbishing it who then put them up!

[Captain Shortwave]

Im a little concerned after viewing the 18Z GEFS ensembles.

http://modeles.meteo...ndres&runpara=0

We have had alot of scatter around the 9th as I highlighted earlier today but the 18Z ensembles show relatively good agreement for the GFS Op.

http://modeles.meteo...ndres&runpara=0

Whilst I hope the UKMO/ECM continue with the same trend these ensembles have placed a seed of doubt in my mind. Lets hope this is just the GFS/GEFS being useless once again.

Agree, in my view its not the fact that the ensembles back the op, but the fact they back that shortwave to the north of Norway dropping south in some way or another destroying the fledgling block over Scandinavia.

Whilst with all it's failings simply put, if gfs is right about that shortwave, then all it's other modelling failings throughout the runs are completely nullified. It will be right and the Atlantic will steam through to about the Russian border.

As you say lets hope it's got that shortwave wrong haha

Edited February 5, 2013 by Captain shortwave

[Dunstable Snow]

GFS has lost all credibility this winter, any GFS run should be taken with a mountain of salt not a pinch

I know that I have been critical of the GFS lately as have many others. There are certainsituations where it performs strongly and it also has a habit of identifying long term changes in synoptic situations but then walking away from them until the mid /.close range ( Particularlycold). This season we have seen scenarioes , as we are seeing now , where the atlantic is coming up against a cold block from the east. In my 9 years of viewing charts and following commentary on the site the GFS has ALWAYS struggled with this scenario. It hardly gets the distribution of energy from a disrupting trough correctly modelled and will invariably send too much energy north and east destroying the block. You only have to view the charts and read the contributions of SM & TEITS ( and others) time and time again this winter.Now is a classic example. IB provides a good balance here with his posts this winter and if the scenario is going to go 'up the spout' he will identify it. My own take on this particular situation is that given the time of year. projected movement of the canadian portion of the vortex , and current position of our cold block we will be very unlucky not to see a protracted cold and, for some, snowy spell. I think GP/BFTP/SM/CH/RJS may well end have having called this right. Time will tell .. but i think the next couple of weeks could be great for us coldies. Cheers

[Panayiotis]

Agree, in my view its not the fact that the ensembles back the op, but the fact they back that shortwave to the north of Norway dropping south in some way or another destroying the fledgling block over Scandinavia.

? Shortwave dropping SE +50% of the ensembles show this and a lot look similar to the ECM/UKMO...

Edited February 5, 2013 by Panayiotis

[Mucka]

It is amazing how people view each chart and run in isolation.

ECM has been very consistent regarding the slider low and trounced the GFS (should it verify,there is still the possibility GFS is right) and cold is secure as far out as charts can be relied upon.

However, although we can not rely on detail at 144+ we can certainly pick out trends and the fact is ECM has slowly trended away from a more amplified pattern behind securing the cold. We are now looking at a very tenuous situation without that amplification to continue the cold beyond the 168 time-frame because we are relying on the block holding to the NE against the flow and hoping the jet buckles to provide another slider which is the only possible way to continue the cold and even then we would still need to see more amplification behind and ridging toward Greenland or rely on the pattern repeating which becomes more and more unlikely. Like rolling a six consecutive times.

To say it is FI, it will change, is a limited view because for that to be true we need ECM and UKKMO to be wrong at 144.

You might say you don't care it is FI, that's cool but if you want to analyse the chances of the sort of deep and prolonged cold through much the rest of winter some are talking up then you had better start hoping for improvements to the west.

ECM offers some encouragement in FI but it needs to avoid all sorts of traps before it gets there.

Its ensembles are solidly behind the slider and the UK remaining within the cold air but thereafter, as expected, we see a lot of scatter and a general warming of the mean.

It is positive though that a tight cluster stay cold beyond the 13th/14th.

Overall a very positive picture for the weekend and early next week but events after the 12th will dictate the pattern for much of the rest of February.

Either we need improvements to the upstream pattern from here or we need to get lucky and have high pressure to our NE hang on against the Atlantic until we get another slider and hope for a better (more secure/sustained blocking) pattern to emerge behind that. Of course there is always the middle ground which would be something not far removed from tonight's ECM with a messy and uncertain battleground scenario continuing with sleet and snow at times but also rain and less cold interludes, no big freeze.

Edited February 5, 2013 by Mucka

[BurwellWeatherWatch]

So GFS is rubbish in the short term & completely wrong, but it's quite okay to put up charts from t300+ because they show a GH. You ave to laarf!

it may not be as daft as this simplistic comment suggests... GFS appears to have been having some modelling issues in 72-144 range of late which makes it output questionable esp in light of ECM et al. however historically ithas been good at spotting longer range trends.

tonight we'd want it to be failing in shortterm and picking a winner in the longer term!

[Don]

Im a little concerned after viewing the 18Z GEFS ensembles.

http://modeles.meteo...ndres&runpara=0

We have had alot of scatter around the 9th as I highlighted earlier today but the 18Z ensembles show relatively good agreement for the GFS Op.

http://modeles.meteo...ndres&runpara=0

Whilst I hope the UKMO/ECM continue with the same trend these ensembles have placed a seed of doubt in my mind. Lets hope this is just the GFS/GEFS being useless once again.

It will certainly be a nervous viewing in the morning that's for sure! I have a bad feeling about this now. Still, all part of the roller coaster ride I suppose!

Edited February 5, 2013 by Don

[swilliam]

Im a little concerned after viewing the 18Z GEFS ensembles.

http://modeles.meteo...ndres&runpara=0

We have had alot of scatter around the 9th as I highlighted earlier today but the 18Z ensembles show relatively good agreement for the GFS Op.

http://modeles.meteo...ndres&runpara=0

Whilst I hope the UKMO/ECM continue with the same trend these ensembles have placed a seed of doubt in my mind. Lets hope this is just the GFS/GEFS being useless once again.

Well I think the ECM ensembles are showing the same - they do not seem to have been posted tonight, probably because they show that after the slider a return to less cold conditions seems to be favoured..