Model Output Discussion 18z 28/07/13

[mushymanrob]

 

yes its time i think to celebrate!

 

yesterdays doubts have been vanquished as

 

 

this has now come into line and shows ridging over us (ok 1 run, but i cant see it being wrong as all the ops agree)

 

as for that pesky shortwave

 

 

looks like missing us, skirting briskly over the northwest, a cloudy introduction to the warmth that follows.

 

my fears were that the ridge infront wouldnt establish, and one (cooler) behind would. this was shown in several model runs. but now its unlikely to evolve like that, and the ridging infront and under the shortwave will introduce hot uppers by wednesday, which will transfer to high surface temps, mid - upper 20's.

 

once the high is in place, it doesnt look like going anywhere fast.... this could be a noteable late summer 'hot' spell.

charts dont come much better then this

[bluearmy]

Note cpc develops an small upper trough (of sorts) over both 6/10 and 8/14 outputs west of iberia.

Early august promised the same scenario but the trough didnt hang around and the plume was brief. The fact that cpc shows this upper feature could well mean it wont quickly eject ne as it did then. The spreads on ecm uppers did not show too much appetite for the uk to receive a marked plume but it could be something that gains strength over the next few runs. Of course, that could also reflect the blocking being strong over us with the trough unable to send the high uppers north over us.

[Captain Shortwave]

Large disagreement at day 5 still, GFS and UKMO look pretty similar and I would feel the preferred solution with the trough absorbed into the building pressure pattern. This is a much wamrer solution than the ECM which allows the trough to survive and sit over Southern Scandinavia.

 

 

GEM is different too with the low still riding over the top of the ridge but unlike the ECM does not cut through the heights

 

There is not one GFS ensemble member which agrees with the ECM solution at day 5, a few have something similar to the GEM and the rest are similar to the GFS op/UKMO output.

So whilst the ECM op is irritating again as it's cooler until the latter frames, it's also the outlier solution at the present time.

[johnholmes]

These are my notes made after seeing the latest ECMWF-GFS and NOAA 6-10 and 8-14 from last evening, and comparing them with what they have each been showing over the past 3-4 days. Looking also at what the synoptic outputs have been showing recently and the anomaly charts from NAEFS. In other words I have tried to take in all outputs that are available from the major centres.

I also took a look at the MJO situation-currently no signal at all that might disturb what other outputs are suggesting. Looking at the forecast and there is some indication of it moving into a ‘usable’ phase 1. In August this equates to blocking to the NW and a trough to the east of the UK. Going from a position close to its origin to this pattern of phase 1 I have no idea how reliable this is of indication of the MJO starting to have an influence-I’ll leave that for more expert opinion.

Below my notes this morning and the output from ECMWF-GFS anomaly charts are in the post from mushy above. NOAA link below

http://www.cpc.ncep.noaa.gov/products/predictions/610day/500mb.php

 

Sat 17 aug

Ec-gfs

Both v similar around uk and quite similar to issue on thur=+ve area showing from states across atlantic into uk and Europe especially on gfs, ec starts +ve area further e of states then similar and both have cut off upper low off nw iberia, much as Thursday

 

All 3 are similar in some ways but not totally, so perhaps they are suggesting something similar for current 6-14 day time scale

Summary might be signs of trough s or sw of uk with possible centre off nw iberia. Also +ve area more pronounced perhaps over uk with 500mb flow less than some predictions, especially noaa, several days ago

Heights shown on all 3 are in excess of 5700dm, nearer 5760dm.

 

This would probably lead to :-

In the current 6-15 day time scale, becoming in most areas, other than possibly the far north west, mostly settled and fairly warm with any sunshine, dependent on cloud cover, with the possible complication of effects from the trough from the sw?

[shedhead]

Large disagreement at day 5 still, GFS and UKMO look pretty similar and I would feel the preferred solution with the trough absorbed into the building pressure pattern. This is a much wamrer solution than the ECM which allows the trough to survive and sit over Southern Scandinavia.

 

 

GEM is different too with the low still riding over the top of the ridge but unlike the ECM does not cut through the heights

 

There is not one GFS ensemble member which agrees with the ECM solution at day 5, a few have something similar to the GEM and the rest are similar to the GFS op/UKMO output.

So whilst the ECM op is irritating again as it's cooler until the latter frames, it's also the outlier solution at the present time.

Indeed CS, it's hard to know why ECM is so persistent in making much more of the midweek LP, but whilst it's still there it really shouldn't be dismissed imo, despite the lack of support from GFS. As for UKMO, not sure what to make of their 144hr either, but at 96 and 120hrs it also has the LP as a player across the north and west in particular. So still far more questions than answers this morning for my money and these charts perhaps go some way to explaining Phil Avery's comments on BBC regarding the media hyped heatwave next week. 

 

Edited August 17, 2013 by shedhead

[Summer Sun]

If GFS is right this morning its going to become hot again and in the south next week temperatures will pushing extremely close to 30c by the end of next week

 

 

By next Saturday 30c is hit

 

 

[Guest William Grimsley]

By next Saturday 30c is hit

 

 

WOW! 30.0°C next weekend! That's going to be good!

[Captain Shortwave]

The ecm ens continue the niggle of this model. To put into perspective every other model and available ensemble mean this morning have the 8C isotherm covering the whole of the UK and higher further south at T120.

ECM ens on the other hand

 

Temperatures still around average in the north.

This is really niggling me as this model is out of sync with pretty much all other output, but as it's the ECM is renowned for being the best model out there, I am left with a lot of doubt this morning on surface conditions. Especially for areas like who live on the east coast.

If any other model except ECM verifies, conditions will become very warm to hot by the end of next week (especially in the south). If the ECM verifies, conditions could be completely different, especially with winds predicted to be north of east which could mean much lower temperatures and the risk of low cloud in eastern areas.

Edited August 17, 2013 by Captain shortwave

[Frosty.]

The GEFS 00z mean is another STONKER this morning until deep into FI, high pressure building in and becoming centred just to the east of the uk which enables very warm and sultry air to drift up across the uk from france, it's really looking good, temperatures look like soaring during next week, up to 27 celsius 81 F by midweek and continuing to soar towards the end of next week with the magic 90 F within reach in my opinion for the south/se but for most of the uk, very warm and sunny with temps into the low 80's F through the second half of next week.

[Frosty.]

Check out the Gefs 00z control run..PHEW WHAT A SCORCHER and then comes the mother of all thundery breakdowns for the south but the heat continues until deep into FI, stunning output, if the control run verified we would be looking at widespread mid 80's F or higher and nearer low to mid 90's F for the south/se before it all goes BANG.

[Frosty.]

The Ecm 00z ensemble mean has a continental look about it, an increasingly warm and sunny outlook next week, after midweek it warms up even more from the south with temps into the low 80's F, closer to mid 70's for the northern half of the uk and then there is a risk of isolated storms breaking out as time goes on, light winds, very warm sunshine, increasing humidity and a glorious bank holiday weekend, the timing of this settled and much warmer spell could not be better, there is no point worrying about early september and breakdowns, the most important thing is the final stages of summer 2013 had an Ace up it's sleeve and produced it just in time..

Edited August 17, 2013 by Frosty039

[Tamara]

Essentially the difference midweek is that the GFS fills the small shortwave a little faster than the ECM, and thus the High pressure cell sitting over southern UK and the nearby continent isn't split by any residual trough, and stays intact as it is reinforced further by the pressure rise behind the shortwave.

 

Having looked at the EPS members, then there is little in it, but it looks as if the GFS solution might be closest. There are a few temporarily messy solutions which split the High pressure cell like the operational, but overall the cleaner evolution to the more general High pressure that goes on to bring the widespread warmth in time for the Bank Holiday looks preferred

 

 

Either way, even if the ECM operational verfiies, it simply delays the warmer uppers getting as far north as quickly as the GFS suggests - but it is pretty warm much countrywide nevertheless as one can see for themselves looking at the model.

 

What all the models agree upon is is the weakness in heights developing from Iberia towards the SW approaches, as a cut off feature underneath the mid latitude ridge across nearby Europe, Baltic areas, UK and into the north atlantic. The orientation of the High determines the approach of the warmer humid uppers which are sitting to the south and are driven by the air around what looks to be a weakish upper trough to the south west.

 

With this in mind, bluearmy makes an important point up the page. With the possibility of the fall in pressure from Iberia into the SW approaches being more of holding pattern due to the upper High being strong enough to prevent it being sent NE too quickly, and thus breaking down the late summer warmth too soon, we could get a situation where the fine spell is sustained with heat not building too fast and then leading to a quick thundery breakdown.The latest GFS coming out does hint at the progressive type of trend option in FI - although a re-build of pressure from the west is indicated thereafter.

 

 

There is a bit of a mix as one might expect a week away with a few solutions following the GFS 06z, but the ECM operational (and a sufficient number of the EPS members) show the holding pattern well - with the cores of the ridge transferring just to the NW and preventing the warm pattern overcooking and the Iberian low not ejecting NE.  The very warmest uppers might not get quite as far north on the one hand, but then again if that sustains the fine spell and keeps temperatures at a tolerable enough level that will please the majority I would think. Best of all worlds perhaps?

 

The strength of the upper High holding across the UK and maybe transferring a little westwards could well be enough to sustain the fine weather beyond the Bank Holiday with any breakdown limited in extent, or temporary in between.

 

Latest NAEFS anomalies underpin the model movements shown as of this morning by and beyond day 10 for the strongest height anomalies to transfer west.  Perhaps just a little cooler and less humid by this time, with the winds switching slightly N of E and still very pleasant - and the overall pattern remains looking good to the end of August

 

Edited August 17, 2013 by Tamara Road

[mushymanrob]

on the subject of sunshine... i dont think itll be bright crystal clear blue skies if we get a feed off the continent...which is likely. i suspect itll become humid, with bright/milky skies as is common with such synoptic set-ups... cloud cover too might be an issue as jh mentioned, especially in the southwestern areas

 

(after wednesday).

[Captain Shortwave]

on the subject of sunshine... i dont think itll be bright crystal clear blue skies if we get a feed off the continent...which is likely. i suspect itll become humid, with bright/milky skies as is common with such synoptic set-ups... cloud cover too might be an issue as jh mentioned, especially in the southwestern areas

 

(after wednesday).

I hope so, just feeling a little nervous with the ECM showing winds north of east. GFS is pretty good again and at T120, again no gfs members go anywhere near the ECM op solution.

Thanks for the post Tamara Road, I am really surprised with the ECM members at day 5, there a large range of solutions showing, from the more typical operationals to more pronounced troughing to our north east giving a northerly wind.

I know I must look like the negative odd one out here. But I must be many of people who live on the east coast where even the slight differences between the models could be the difference between low-mid twenties and glorious sunshine and grey skies with temperatures of 17-18C.

I will be a lot happier when the ECM drops the significance of that shortwave, the op shows it having an effect all the way to day 10 btw on the previous op run.

Edit - GFS ens still happy to get the mean uppers up to 14C in the south by the end of the week.

Edited August 17, 2013 by Captain shortwave

[Frosty.]

The Gfs 06z in the high res is superb, becoming warmer and warmer and sunnier as next week goes on, eventually the warmth reaching northern scotland and becoming hot across the southern half of the uk, locally very hot in the far south/se with 30-32 celsius possible by the end of next week but with an increasing risk of thundery rain breaking out towards the end of next week but hit and miss, some areas remaining hot with hazy sunshine, after next weekend the 6z becomes a cool unsettled outlier in my opinion, I think the heat or at least the warmth will persist for much longer than this op run shows.

[Tamara]

I hope so, just feeling a little nervous with the ECM showing winds north of east. GFS is pretty good again and at T120, again no gfs members go anywhere near the ECM op solution.

Thanks for the post Tamara Road, I am really surprised with the ECM members at day 5, there a large range of solutions showing, from the more typical operationals to more pronounced troughing to our north east giving a northerly wind.

I know I must look like the negative odd one out here. But I must be many of people who live on the east coast where even the slight differences between the models could be the difference between low-mid twenties and glorious sunshine and grey skies with temperatures of 17-18C.

I will be a lot happier when the ECM drops the significance of that shortwave, the op shows it having an effect all the way to day 10 btw on the previous op run.

I think that the METO are being cautious in respect of the fair points you make as well...plus more especially so with the August Bank Holiday coming up. The tentative hint at temporarily more unsettled weather over that weekend further south conceivably reflects what is, atm, the low possibility of the Iberian trough coming NE..much as hinted at in the latest GFS output. But they have to cover bases this far out as expected

Edited August 17, 2013 by Tamara Road

[J10]

I think western areas could do very well out of this to be honest, it has been a few times this summer that low pressure has attempted to nudge in from the South West in such scenarios and they haven't materialised to spoil the fun, I think the first occasion that this was forecast was Early June but the High reestablished itself and the first 10 days were glorious.

 

http://meteociel.com/modeles/archives/archives.php?day=5&month=6&year=2013&hour=0&map=0&mode=0

http://meteociel.com/modeles/archives/archives.php?day=7&month=6&year=2013&hour=0&map=0&mode=0

http://meteociel.com/modeles/archives/archives.php?day=9&month=6&year=2013&hour=0&map=0&mode=0

 

When a breakdown similar to that of today's GFS was originally suggested.

 

The start of August which did give buckets of rain was more of a plume rather any HP over the UK.

 

If ECM come off, any threat of this is very much minimised with the Trough way out to the west, until about T+216. (Eastern areas probably wouldn't love this setup)

 

More of a risk according to GFS, abut even then High Pressure quickly re-establishing itself from the west.

 

In any case, A much better end to august is on the cards than is normally the case.

Edited August 17, 2013 by J10

[Frosty.]

Another stunning ensemble mean, this time the GEFS 06Z mean which shows much warmer air spreading up from the south as next week goes on with an anticyclone becoming centred to the east of the BI controlling our weather but a thundery plume begins to push north through france and may bring a risk of thundery rain or scattered storms at the end of next week but very hit and miss, some areas would remain hot and hazy while others get a deluge, high pressure migrates further north on this run with the hot, sultry airmass following it north into the uk, temps would soar into the low to mid 80's F and possibly low 90's F across the far south/se and the 6z mean looks way better than the 6z op run in FI with the PFJ forced way north into the arctic, so a fantastic burst of late summer is only a few days away, it may take a few extra days for the northwest of the uk to settle down but it should be worth the wait, summery weather is coming back.

[James M]

When was the last time we had a warm settled spell at the end of August/ beginning September? Thinking back we always seem to have an unsettled spell at this time if year.

[bubsy83]

When was the last time we had a warm settled spell at the end of August/ beginning September? Thinking back we always seem to have an unsettled spell at this time if year.

 

2005 I think.

[Captain Shortwave]

Pretty good agreement between the GFS and UKMO at T120

 

T144

 

GFS starting to move to the Euro models on that cut off low now.

 

12-16C uppers over the UK, not bad

No movement towards the ECM solution which is good news

Would bank this run for bank holiday excitement, Friday and Saturday would have highs of 30C in the South, even hotter on Sunday with the T192 chart showing 31C at midday. Add to that thunderstorms would be breaking out widely as the trough from the south west approaches our shores.

Safe to say I feel a bit better now. Now for the ECM to drop it's shortwave path of destruction and misery for me 

Edited August 17, 2013 by Captain shortwave

[East_England_Stormchaser91]

We begin to see an absolute mother of a plume being shown on the 12z GFS!

[Tamara]

At this stage, at least, the suspicion is that the GFS is being rather progressive with the pattern beyond days 5/6 - especially at this distance..until, or if, the ECM also moves the thundery trough closer. The overall support this morning was for it to be held further west. However, there is plenty of time for things to move one way or the other and we can see already that the Bank Holiday might not be straightforward like so many Bank Holidays in this country!

Edited August 17, 2013 by Tamara Road

[Captain Shortwave]

At this stage, at least, the suspicion is that the GFS is being rather progressive with the pattern beyond days 5/6 - especially at this distance..until, or if, the ECM also moves the thundery trough closer. The overall support this morning was for it to be held further west. However, there is plenty of time for things to move one way or the other and we can see already that the Bank Holiday might not be straightforward like so many Bank Holidays in this country!

I think many would take rain during the bank holiday if it comes with the crash bang wallop symphony orchestra  

And of course some proper warmth

At T120, all gfs ensemble members show high pressure dominant over the UK or to the north east, no member shows anything remotely similar to this mornings ECM output. Sure the ECM will move back to the other models.

Strong support for a full blown Scandi high

 

 

I guess the upper trough to the south west is starting to show up on the GFS now, this needs to be watched for either a surge of heat from Europe and also the possibility of some thundery activity.

Edited August 17, 2013 by Captain shortwave

[Frosty.]

Sensational Gfs 12z in the high res as we draw hot & sultry continental air up from the south and unlike the 6z which was more of a glancing blow, the 12z is a direct hit of heat which builds and builds and eventually it all goes BANG early the following week but in the week long build up it would bring a fabulous spell of weather with lots of strong sunshine and just the risk of an isolated heavy thundery shower being sparked by the building heat, really continental weather, perfect for BBQ's and very warm evenings with muggy nights, a real taste of british summer at it's very BEST. During low res the gfs goes into default mode but even then, pressure remains higher to the south and southwest with more dry and fine spells but with temperatures gradually returning to average, but low res is like trying to pin the tail on the donkey, the important part of the run is memorable.