Model Output Discussion 30/06/2012

[chionomaniac]

Yes,

It's looking more and more likely that those extended ECM ensembles could be right. From being a weak trough in a sea of higher pressure, we are now looking at a more dominant trough for next weekend, going by tonights ECM.

I still suspect that this will shift easier east than previous troughs this summer.

Edited July 21, 2012 by chionomaniac

[nick sussex]

just have to laugh at this shocking output by the ECM for the end of next week

http://www.meteociel...CM1-168.GIF?21- we are back to square one, make the most of this summary spell over the next few days

Yes its really dismal for the start of the Olympics, what a shame considering its looking very summery for London till Thursday.

It's a case of just hoping that we can find a dry window for a few hours during the Opening Ceremony, its all looking very complicated with low pressure heading north out of France and that shortwave heading se in towards the UK.

[Summer Sun]

Not a bad end to ECM we've had much worse this summer, places like the channel Islands would be best with the chart below

[shedhead]

Oh dear, just when you thought it couldn't get any worse it does, with ECM coming up with an absolute horror show as early as T+144hrs. Once again the main European Model has been dragged screaming and kicking into line with the much maligned and it's fair to say much abused GFS, which picked up this evolution 48hrs ago and has ran with it consistantly ever since. This one looks another very good case in point of looking at and commenting on what you see, not what you want to see.

Edited July 21, 2012 by shedhead

[chionomaniac]

Oh dear, just when you thought it couldn't get any worse it does, with ECM coming up with an absolute horror show as early as T+144hrs. Once again the main European Model has been dragged screaming and kicking into line with the much maligned and it's fair to say much abused GFS, which picked up this evolution 48hrs ago and has ran with it consistantly ever since. This one looks another very good case in point of looking at and commenting on what you see, not what you want to see.

So commenting on what the ECM showed for the last 48 hours was not that?

Come on shed, you can do better than that.

[shedhead]

No Chio, the point here being GFS picked this up 7 runs ago, but as is often the case both Summer and Winter most dismissed it, NOT because the evolution was in any way inplausible, simply because it was unpalatable. GFS does have a knack of spotting changes 24-48hrs in advance of ECM, sometimes those changes manifest themselves sometimes they don't, but you would think from the abuse GFS gets when it picks up an unwanted change it's always wrong. You and I both know that simply isn't the case and wasn't here.

[chionomaniac]

No Chio, the point here being GFS picked this up 7 runs ago, but as is often the case both Summer and Winter most dismissed it, NOT because the evolution was in any way inplausible, simply because it was unpalatable. GFS does have a knack of spotting changes 24-48hrs in advance of ECM, sometimes those changes manifest themselves sometimes they don't, but you would think from the abuse GFS gets when it picks up an unwanted change it's always wrong. You and I both know that simply isn't the case and wasn't here.

It was never dismissed shed, because it was unpalatable, moreso that, as you readily admit, the GFS has a habit of 'crying wolf', so that we do not have that type of trust in it that we would like.

Until the other models support the GFS then what it shows will always be treated with suspicion. No more, no less.

And the long term verification stats back that assertion up.

Oh and there was one poster after the first GFS run used 'gut instinct' rather than what the rest of the models were showing at the time. If ever that there was a case of looking for what you wanted to see rather than what the majority of the models were showing then that was it. Luckily for you this time that your gut instinct proved correct!

Edited July 21, 2012 by chionomaniac

[Cloud 10]

GFS is doing better than it has done in a long time on recent verification,running a close second

to the ECM.

Model verification

[phil nw.]

Warning signs that any settled spell was liable to be rather brief have been showing for a few days in the NAEF`s Pressure Ens outputs with some support over the last 3 days from the NOAA 8-14days.

Both outputs place the core of any heights to our west in the Atlantic with a blue Anomol.area developing over Scandinavia by the end of next week.

This is always likely to leave a window for some energy over the top of the high and this shows on all models now.

The more recent development fo a thundery breakdown off the continent has certainly stirred the pot.

[bluearmy]

The amplification of the ridge into greeny is dependant on the exit of the depression off the eastern seaboard. the more WAA generated, the sharper the ridge and the further south the shortwave will dig to our west. If there is less WAA, the ridge will be a bit flatter and the shortwave will head on a more se path, probably crossing the north of the uk. Either way, it appears that we get a thundery low headed ne from Iberia towards us. No guarantee that this thundery low won't pass to our se. At the moment , we look to be headed for a direct hit but fri is still quite a way off.

[shedhead]

It was never dismissed shed, because it was unpalatable, moreso that, as you readily admit, the GFS has a habit of 'crying wolf', so that we do not have that type of trust in it that we would like.

Until the other models support the GFS then what it shows will always be treated with suspicion. No more, no less.

And the long term verification stats back that assertion up.

Oh and there was one poster after the first GFS run used 'gut instinct' rather than what the rest of the models were showing at the time. If ever that there was a case of looking for what you wanted to see rather than what the majority of the models were showing then that was it. Luckily for you this time that your gut instinct proved correct!

Soundbites are OK Chio, but they don't tell the full story. This was one of a number of posts from me in this thread and was in response to a direct question....... I've seen no evidence on the 500mb charts that the main trough can build and maintain itself to our east, plus a strong gut feeling born out of seeing plenty of other similar situations in the past.

Not really sure either about the correlation between gut feeling and looking for what you want to see. Are you suggesting people only get a gut feeling about how things might pan out if it's untimately what they want to see happen?

Edited July 21, 2012 by shedhead

[ANYWEATHER]

Hats off to Gfs, it does get a lot of flack,but it has set the trend in recent days! No point fighting online as to which model is best! Anyway back to the models, and lots of heat and humidity for the south in the next week, then the north cental areas, plagued by that cold front...Looks as though some very thundery conditions developing later in the south by Thursday/Friday.....

[legritter]

just want to say a thankyou to previouse posters tonight for their input with charts and data ,my com puter is running low on vir memory , think i will log of and have a break . we now have ECM getting in more on the act ,looking foreward to end of next week ,will it be suncream or umbrellas or a free steam bath from mother nature .cheers

[snowfluff]

DeBit ensembles..

http://www.knmi.nl/e...agse/index.html

Note the ppn flatlining. That's a location east of ours, so even more pronounced drier theme for us on probability that the ridge to our west is a secure feature in the modelling.

This all becomes about the modelling of heights over the Arctic. There will be some phases where blocking looks to return, but over the mean 6 week period, I suggest that the blocking signal is declining, which should correspond with angular momentum becoming less negative and a shift in MJO forcing towards phases 3-4. Interesting that the ECM / UKMO tropical component is different to GFS / GEM, being more positive on a shift towards phase 3 in time. That should maintain the mean ridge position in the Atlantic at least longitude between Azores and Iceland (i.e. close enough to influence our weather pattern) and potentially coming closer in time.

Or not, good call by Shedhead.

[nick sussex]

Looking at all the model output its looking like some very warm conditions for southern and central areas areas upto Thursday, with perhaps 30c being hit towards the se.

Unfortunately northern areas look like being plagued by a slow moving front for much of that time. So not great I'm afraid, further north towards Scotland could see some decent sunshine but cooler conditions, this front is likely to oscilate so some margin for error within that.

Now Friday becomes extremely complicated, thundery low pressure is expected to edge north out of France, at the same time a shortwave tracking se'wards will likely bring some showery rain to the nw.

We are likely to see some intensification of the precip at the boundary between that warmer humid air and cooler nw flow and this frontal division could become slow moving before finally edging away to the east and se.

The ECM does suggest that theres a chance high pressure could edge in to more southern areas in the later outlook but its hard to have a great deal of confidence in any of the output past 168hrs.

Looking at the ECM ensemble maps you can see still quite some variation with that thundery low over France:

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!156!pop!od!enfo!enplot!2012072112!!/

In terms of the Olympics Opening Ceremony, I must admit its not looking great, and we won't know till nearer the time when we can see expected troughs and the timing of that thundery low, some GEFS members do hold the main precip over France till early Saturday, normally many of us in winter are chasing the snow here I'm just trying to find a dry window beginning 9pm Friday!

[chionomaniac]

Or not, good call by Shedhead.

So 3 days into a mean 6 week period you are dismissing GP's thoughts?

At least read the post properly that you are quoting.

[PolarWarsaw]

iv had a look today on sites all over or most i should say around the northern hemisphere . and the jet seems to be all over the place for this time of the year .i know this is often the case but reading weather forums from US/CANADA .ACROSS TO US AND OUT INTO EUROPE AND BEYOND THERE SEEMS TO BE ALOT OF CONFUSION FROM POSTERS IN MANY COUNTRYS .SO AT THE PRESENT THE LIKES OF OUR SHORES SEEMS TO BE HARD TO PIN DOWN AS REGARDS POSITIONING OF MAIN HIGH PRESSURE SYSTEMS . THE JET IN SOME PARTS SPLITTING MORE THAN USUALL .IM GOING TO HOLD MY HOPES ON THE WEATHER FOR NEXT WEEK UNTILL LATER TOMORROW AFTER ANOTHER 3 RUNS OF THE BIG 3 PLUS SUN FAX AT AROUND 10.30 PM .AT THE MOMENT GOING BY OUR CHARTS THE BIG QUESTION MARK STARTS ABOUT MID DAY NEXT WEDNESDAY .

I dont mean to be rude, con-descending or arrogant in anyway - but for the benefit of myself and more importantly the forum...

'Ive had a look on sites today all over, or should i say most in the Northern Hemisphere anyway and imo the jet stream seems to be all over the place for the time of year, I no this is often the case but reading weather forums from the US/Canada and across to the likes of us, out into europe and beyond there seems to be a lot of confusion from many posters in many countries. At present the likes of the UK seem to be far harder to pin down with regards to the positioning of the high pressure next week. The jet seems to be splitting in many places. Im going to hold getting my hopes up for next weeks potential warm weather until late tommorrow evening after another 3 runs from the big guns, plus the FAX charts. At the moment i'd pin-point Wednesday afternoon as the day in question'.

I actually want to read your posts as the content, generally speaking is 100% on. But i get stuck around 3 lines in because its just impossible to read. I did the purely to help other posters and myself read your post, which was a very good one.

Edited July 21, 2012 by Radders

[phil nw.]

Yes a good summery Nick.Tis very uncertain on surface conditions come Friday but the thermal gradient is likely to give some of us a soaking as it currently looks.

All eyes on the fax`s for clues later-although at this distance they are liable to change as we get nearer.

[Glacier Point]

So 3 days into a mean 6 week period you are dismissing GP's thoughts?

At least read the post properly that you are quoting.

..indeed, this ridge hasn't gone away.

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

and angular momentum increasing, GWO in phase 3..

http://www.esrl.noaa.gov/psd/map/images/gcm/gwo_40d.gif

End of next week looks extremely complicated, where will the trough disrupt if at all, will the upstream amplification be as sharp as forecast ? Yet we still end up with the ridge to our west and the trough to our east.

[PubliusEnigma]

Can anyone with an experienced eye enlighten me with my question?

Well the latest fax for Tues has the front further north

And 564 dam air close to the borders.. Very warm south of the warm front circa 28 - 30oC and very warm overnight around 20oC

[bluearmy]

a quick look at the gefs members for thurs into friday leads me to think that there is no certainty that the trough will dig as far south as currently looks likely from the op runs. given the thundery low trundling ne, this is quite a complex set up. you could easily end up with a different shape to the shortwave exiting the states and the ridge extending east pushing the thundery low to our se and preventing the trough from making it further south than northern england.

[phil nw.]

..indeed, this ridge hasn't gone away.

http://www.cpc.ncep....14day/500mb.php

and angular momentum increasing, GWO in phase 3..

http://www.esrl.noaa...gcm/gwo_40d.gif

End of next week looks extremely complicated, where will the trough disrupt if at all, will the upstream amplification be as sharp as forecast ? Yet we still end up with the ridge to our west and the trough to our east.

Hi Stewart,

Yes that`s a fair assesment of the general wave pattern but it`s the exact placement that`s open for debate i guess.

The core of the high is being modelled too far west in the medium term and we are liable to some less than settled conditions for a while.

That upper trough around Nw Europe isn`t going far by the looks.

[nick sussex]

Yes a good summery Nick.Tis very uncertain on surface conditions come Friday but the thermal gradient is likely to give some of us a soaking as it currently looks.

All eyes on the fax`s for clues later-although at this distance they are liable to change as we get nearer.

Thanks Phil, yes its looking like a very difficult forecast, I'm still not convinced that this shortwave track is anywhere close to being sorted out.

I think the main risk for the soaking in terms of frontal rain is for more central north areas, the thundery low heads north and sort of hits a brick wall as that high is trying to build se'wards. I would have thought the main thermal gradient would be there.

Anyway theres along way to go till then, hopefully we can see a turnaround at least to spare the Opening Ceremony.

[Interitus]

GFS is doing better than it has done in a long time on recent verification,running a close second

to the ECM.

Model verification

The GFS model has received numerous upgrades in recent months which may account for this.

[Alex]

..indeed, this ridge hasn't gone away.

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

and angular momentum increasing, GWO in phase 3..

http://www.esrl.noaa.gov/psd/map/images/gcm/gwo_40d.gif

End of next week looks extremely complicated, where will the trough disrupt if at all, will the upstream amplification be as sharp as forecast ? Yet we still end up with the ridge to our west and the trough to our east.

Agreed, angular momentum on the rise again and GWO in an amplified phase 3 position, surely even with a blip on Friday night/Saturday, a possible repeat could occur the following week with less heat as the core of the ridge is to the west.