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Model Output Discussions 12z 01/06/2017


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Perhaps we need to be looking in the nearer timeframes for some interest as midweek is starting to look very interesting.

gfs-0-102.png?6

The GFS has quietly come into agreement with the ECM for a brief warm up midweek with the 16C isotherm pushing into the south with the chance of thundery downpours pushing across the southern half of the UK during Wednesday night and Thursday. Mid twenties possible on Wednesday, possibly higher if the high can get a little further north as there is some serious heat building to our south at the start of the week.

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An unseasonally wet, cool and windy day amidst an underwhelming week of weather does not a summer make. Much as anticipated through the second half of Spring, the hand-over to Summer sees the atm

There have been some strange observations made today, as too often occurs in this thread whatever the time of year, and largely based on the usual knee-jerk response to longer term suggested NWP.

You always seem to jump in on my posts, along with a few others. Why don't you try giving your assessment of the models instead of picking holes in others efforts!

Posted Images

gfsgwo_1.png

The retraction west of the ridge is really bugging me - it's not part of the script for the month when going by historical precedent. It ties in with the big drop in GLAAM being advertised by  GEFS and it seems this must be present to some extent in the ECM guidance now as well. 

Looking at global convective coverage, I can see what looks to be a tropical cyclone near to the Bay of Bengal - perhaps this is a factor in the models depicting a La Nina-like pattern shift. Question is then how legitimate the level of response is. I expect GFS/GEFS to be over-the-top as usual so those runs showing a mean Scandi trough edging west toward us to produce a lot of trashy weather aren't causing me concern at this stage... but it could well be that we see a 'gentle northerly' type regime as per the ECM 00z days 9-10 which would result in mean temps quite a bit lower than the majority of long-range guidance was suggesting back at the end of May (mostly due to cool nights).

I'm not sure though; we've been here before with the models depicting an undesirable pattern shift only for a Euro ridge to find its way into the equation after all, so at the moment I am inclined not to take the output all that seriously beyond a few day's range. After all there's that shallow low from Europe to be resolved, which as usual GFS is keen to lift out swiftly NE while the other models would rather let it stew over the continent with little direct impact on us.

Why can't it just be a simple outcome for a change? :wallbash::rolleyes::laugh:

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15 minutes ago, Singularity said:

gfsgwo_1.png

The retraction west of the ridge is really bugging me - it's not part of the script for the month when going by historical precedent. It ties in with the big drop in GLAAM being advertised by  GEFS and it seems this must be present to some extent in the ECM guidance now as well. 

Looking at global convective coverage, I can see what looks to be a tropical cyclone near to the Bay of Bengal - perhaps this is a factor in the models depicting a La Nina-like pattern shift. Question is then how legitimate the level of response is. I expect GFS/GEFS to be over-the-top as usual so those runs showing a mean Scandi trough edging west toward us to produce a lot of trashy weather aren't causing me concern at this stage... but it could well be that we see a 'gentle northerly' type regime as per the ECM 00z days 9-10 which would result in mean temps quite a bit lower than the majority of long-range guidance was suggesting back at the end of May (mostly due to cool nights).

I'm not sure though; we've been here before with the models depicting an undesirable pattern shift only for a Euro ridge to find its way into the equation after all, so at the moment I am inclined not to take the output all that seriously beyond a few day's range. After all there's that shallow low from Europe to be resolved, which as usual GFS is keen to lift out swiftly NE while the other models would rather let it stew over the continent with little direct impact on us.

Why can't it just be a simple outcome for a change? :wallbash::rolleyes::laugh:

Extended ecm ens continue to advertise s scuero upper ridge rather than trough. Also trend towards Atlantic upper trough edging close to nw Europe. I don't see a retrogression of the heights/scandi upper trough although the surface features could ebb and flow around pulsing Azores/euro ridge and Atlantic systems running sw/ne or w/e as they are currently or seems likely thurs/fri.  Generally fine outlook though always south biased 

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41 minutes ago, Singularity said:

Why can't it just be a simple outcome for a change? :wallbash::rolleyes::laugh:

Could it be because we live on a little island called the uk next to the Atlantic ocean..just a thought:D 

Edited by Frosty.
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50 minutes ago, bluearmy said:

Extended ecm ens continue to advertise s scuero upper ridge rather than trough. Also trend towards Atlantic upper trough edging close to nw Europe. I don't see a retrogression of the heights/scandi upper trough although the surface features could ebb and flow around pulsing Azores/euro ridge and Atlantic systems running sw/ne or w/e as they are currently or seems likely thurs/fri.  Generally fine outlook though always south biased 

Thanks for that encouraging information BA, one day I will pay for access to the extended EC ens again - probably ready for it to dangle many carrots next winter :p

Edited by Singularity
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Well it's a lovely day in the south and south-east today with plenty of sunshine and temperatures around 23-24c 74f. Looking at the Ecm 00z ensemble mean shows a generally summery outlook with Azores high influence, especially for the south with predominantly warm / very warm conditions with some dry and sunny weather but also a risk of thundery showers and high humidity at times from the near continent..looking further ahead, above average temps are still indicated with a good chance of very warm / hot spells..could be worse!:D

DB70qO3XcAE9qnm.jpg

DB9NlvuXoAAEcfA.jpg

ECMAVGEU00_144_1.png

ECMAVGEU00_168_1.png

ECMAVGEU00_192_1.png

ECMAVGEU00_216_1.png

ECMAVGEU00_216_2.png

ECMAVGEU00_240_1.png

Edited by Frosty.
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12 minutes ago, bluearmy said:

tempresult_vsj3.gif

 

A good old illustration of where the clustering agains that mean exists Karl.  Reveals where the upper troughing is most likely to run against the ridging. 

Any chance that sequence can go a bit faster:laugh:

back to these again as they are the only ones i seem to be able to post.....

 ensemble-tt6-london.gif

ensemble-rrrcum-london.gif

looks very nice indeed:).........plenty of very warm runs.

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Not an overly exciting 12z thus far, a real effort to get any high pressure in, and it now looks as though it's going to get pulled West and leave us in a yucky northerly airflow after. Better enjoy what decent stuff does turn up, as it may be a fleeting visit.

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7 minutes ago, mb018538 said:

Not an overly exciting 12z thus far, a real effort to get any high pressure in, and it now looks as though it's going to get pulled West and leave us in a yucky northerly airflow after. Better enjoy what decent stuff does turn up, as it may be a fleeting visit.

I must be looking at a different Gfs 12z to you..the week ahead shows plenty of high pressure and warmth, especially further south..the high then does pull west for a time before drifting east into the uk during low res.

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2 minutes ago, Frosty. said:

I must be looking at a different Gfs 12z to you..the week ahead shows plenty of high pressure and warmth, especially further south..the high then does pull west for a time before drifting east into the uk during low res.

Well, Monday 19th is vile! 14° max, will feel raw in the northerly winds, and no doubt wet here, as showers stream through the Cheshire Gap

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=216&mode=0

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Just now, I remember Atlantic 252 said:

Well, Monday 19th is vile! 14° max, will feel raw in the northerly winds, and no doubt wet here, as showers stream through the Cheshire Gap

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=216&mode=0

It looks much better for most of next week though but some prefer to gloss over that.

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4 minutes ago, I remember Atlantic 252 said:

yes, mini plume still there for Wednesday, just cannot help looking ahead

Looking ahead you serious?? take more than  5 days ahead serious..The models struggle to get anything right after that.. As its been shown over and over again..

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5 minutes ago, weatherguru14 said:

Looking ahead you serious?? take more than  5 days ahead serious..The models struggle to get anything right after that.. As its been shown over and over again..

Its a vile run, Wednesday/Thursday looks the best before HP drifts out west leaving a N'ly and then the run ends with Greenland blocking sending a 992mb crap fest over us. Long way off yet.

 

 

crap.png

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21 minutes ago, 40*C said:

Its a vile run, Wednesday/Thursday looks the best before HP drifts out west leaving a N'ly and then the run ends with Greenland blocking sending a 992mb crap fest over us. Long way off yet.

 

 

crap.png

haha thats the  26th of  June  16 Days away.. I

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the noaa anomaly charts dont currently suggest the retrogressing high. maybe they will shift tonight, maybe not.

but we have been here before with a much vaunted anticyclonic spell being picked up, then dropped or modified by the ops, before being re-instated . so ill not worry too much about a retrogressing ridge until the anomaly charts go for it.

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There retrogression of the high comes about from a strong jetstreak upstream which quickly removes the Atlantic trough and cuts off and area of low heights towards the Azores, the question is is this process being too quick and hence we see the trough sustained for long and allows the ridge to push further north east and instead of seeing this.

gfs-0-192.png?12

We see this....

gem-0-192.png?12

GFS turns cool but fairly dry, the GEM develops heatwave conditions as the powerful high drifts east and a lot of hot air trapped beneath it allowed to push northwards with temperatures by the end of the run pushing easily into the low thirties. 

GEFs favour the GFS op at the moment

gens-21-1-192.png   gens-21-1-240.png   gens-21-1-300.png

Developing an Scandi trough, too be honest one of those cool but dry and quite cloudy set up as the stability is too high to allow much convection so sunny mornings/evenings but a lot of cloud during the middle of the day. Still a long way to go yet and we we still see some warm/very warm weather midweek with the risk of thundery showers breaking out.

Arpege for Wednesday

arpegeuk-41-100-0.png?10-18

Not too shabby if you ask me if that came off. Also looking at the ECM coming out, it has a much better solution to the mornings run with a much broader Atlantic trough at day 6/7.

Edited by Captain Shortwave
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22 minutes ago, Captain Shortwave said:

There retrogression of the high comes about from a strong jetstreak upstream which quickly removes the Atlantic trough and cuts off and area of low heights towards the Azores, the question is is this process being too quick and hence we see the trough sustained for long and allows the ridge to push further north east and instead of seeing this.

gfs-0-192.png?12

We see this....

gem-0-192.png?12

GFS turns cool but fairly dry, the GEM develops heatwave conditions as the powerful high drifts east and a lot of hot air trapped beneath it allowed to push northwards with temperatures by the end of the run pushing easily into the low thirties. 

GEFs favour the GFS op at the moment

gens-21-1-192.png   gens-21-1-240.png   gens-21-1-300.png

Developing an Scandi trough, too be honest one of those cool but dry and quite cloudy set up as the stability is too high to allow much convection so sunny mornings/evenings but a lot of cloud during the middle of the day. Still a long way to go yet and we we still see some warm/very warm weather midweek with the risk of thundery showers breaking out.

Arpege for Wednesday

arpegeuk-41-100-0.png?10-18

Not too shabby if you ask me if that came off. Also looking at the ECM coming out, it has a much better solution to the mornings run with a much broader Atlantic trough at day 6/7.

Look at them Temps in France getting up to 44c Blimey ' Talk about schorchio .

Edit : 46 Gulp

Edited by A Frayed Knot
rephrase
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Many thanks for that Tamara. It explains in great detail what I have only had time to apply in the form of suggestions that the longer-term GFS/GEFS is likely too far west with the ridge. Meanwhile ECM and the EC ens appear to be much less prone to this sort of misjudgment - less prone, but not immune.

Given the above, I am very interested in the fact that ECM is not all that different on day 7 to GEM, and only goes away from the hot weather scenario as a result of further amplifying the pattern such that the ridge extends north rather than locking into place.

168_mslp850.png?cb=628 168_mslp850.png?cb=628

The day 9-10 GEM charts deserve to be posted out of admiration of what's just about possible if all manner of things fall into place;

216_mslp850.png?cb=628 240_mslp850.png?cb=628

It requires the right balance of LP areas making it across to the east of the UK and staying west of the UK, such that the ridge does not venture away from us. 

219_uk2mtmp.png?cb=628 240_uk2mtmp.png?cb=628

These I am posting for the sheer fun of it :D. I daresay GEM is on course for a maximum near 34*C somewhere in the SE on Tuesday 20th. 

Not that where ECM goes is without its merits;

216_mslp850.png?cb=628 240_mslp850.png?cb=628

Western areas would fare nicely out  of that, eastern areas less so - though the anomalous warmth that have been widespread in the North Sea so far this month would help to mitigate the ability of low cloud to advance inland.

With the blocking to the NE standing in stark contrast to GFS' blocking to the west, the difference in model bias could hardly be better illustrated.

 

Now as much as I'd like to, I can't go ignoring the UKMO 12z, unfortunately;

Rukm1201.gif Rukm1441.gif

This is extremely progressive but it occurs as a result of there being no new trough moving in to interact with the pre-existing one in the mid-Atlantic on day 5. All other models have this feature developing so UKMO really stands out with the lack of such an outcome. Even so. it serves as a reminder that even at 5 days range major changes remain possible.

In fact it's 4 days at the moment given that GFS still has the shallow Iberian low moving much closer to our shores than the other models do. More runs needed!

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Clear differences appearing between the GFS and ECM suites now

EDM1-144.GIF?10-0   EDM1-192.GIF?10-0   EDM1-240.GIF?10-0

The Euro ridge remains intact out to day 10 though how far north its influence goes is up for debate, a stark difference to the ridge retrogressing strongly to our west as per the GEFs.

So ECM going for settled and warm or more changeable but still warm whilst the GEFs go for dry in the west and cool and possibly showery in the east in the longer term.

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